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Cancer

By Nazar A. Mahmood

PhD StudentCommunity medicine department

College of MedicineHawler Medical University

2016

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The word cancer is derived from the Latin word for crab because cancers are often

very irregularly shaped, and because, like a crab, they "grab on and don't let go."

Cancer:

“Group of heterogeneous disorders characterized by Clonality, Autonomy, Anaplasia

and Metastasis”.

The reason is that cancers, as they are defined, are

− Clonality: arise from a single stem cell that clones into carcinomatous cells.

− Autonomy: the cell division and growth is uncontrolled.

− Anaplasia : lack of cell differentiation.

− Metastasis: (distant spread)”.

Definition

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Neoplasm:

A neoplasm is an abnormal new growth of cells. The cells in a neoplasm usually grow more rapidly

than normal cells and will continue to grow if not treated. As they grow, neoplasms can impinge

upon and damage adjacent structures. The term neoplasm can refer to benign (usually curable) or

malignant (cancerous) growths.

Tumor:

is a commonly used, but non-specific, term for a neoplasm. The word tumor simply refers to a

mass. This is a general term that can refer to benign (generally harmless) or malignant (cancerous)

growths.

Mutation

is a permanent alteration of the nucleotide sequence of the genome of an organism, virus, or

extrachromosomal DNA or other genetic elements.

Definition

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Pathophysiology

Cancer can start almost anywhere in the human body, which is made up of trillions of cells. Normally, human cells grow and divide to form new cells as the body needs them. When cells grow old or become damaged, they die, and new cells take their place.

When cancer develops, however, this orderly process breaks down. As cells become more and more abnormal, old or damaged cells survive when they should die, and new cells form when they are not needed. These extra cells can divide without stopping and may form growths called tumors.

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Pathophysiology

Cancer is a genetic disease—that is, it is caused by changes to genes that control the way of cells function, especially how they grow and divide.

Genetic changes that cause cancer can be inherited from parents. They can also arise during a person’s lifetime as a result of errors that occur as cells divide or because of damage to DNA caused by certain environmental exposures. Cancer-causing environmental exposures include substances, such as the chemicals in tobacco smoke, and radiation, such as ultraviolet rays from the sun.

Each person’s cancer has a unique combination of genetic changes. As the cancer continues to grow, additional changes will occur. Even within the same tumor, different cells may have different genetic changes.

In general, cancer cells have more genetic changes, such as mutations in DNA, than normal cells. Some of these changes may have nothing to do with the cancer; they may be the result of the cancer, rather than its cause.

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Classification

1. Carcinoma: Cancers derived from epithelial cells. This group includes many of the most

common cancers, particularly in the aged, and include nearly all those developing in

the breast, prostate, lung, pancreas, and colon.

2. Sarcoma: Cancers arising from connective tissue (i.e. bone, cartilage, fat, nerve),

each of which develops from cells originating in mesenchymal cells outside the bone

marrow.

3. Lymphoma and leukaemia: These two classes of cancer arise from hematopoietic

(blood-forming) cells that leave the marrow and tend to mature in the lymph nodes and

blood, respectively. Leukaemia is the most common type of cancer in

children accounting for about 30%.

4. Germ cell tumor: Cancers derived from pluripotent cells, most often presenting in the testicle or the ovary (seminoma and dysgerminoma, respectively).

5. Blastoma: Cancers derived from immature "precursor" cells or embryonic tissue. Blastomas are more common in children than in older adults.

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Danger signs

Lump/hard area in breast.

Sudden change in a previous wart/mole.

Persistent change in bowel habit (constipation/ diarrhoea /bleeding).

Persistent cough/hoarseness.

↑ menstrual blood loss/ metrorrhagia.

Blood loss from any natural orifice.

Swelling/ sore throat that does not heal.

Unexplained weight loss.

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Stages of Cancer

Stage 0. This stage describes cancer in situ, which means “in place.” Stage 0 cancers are still located in the place they started and have not spread to nearby tissues. This stage of cancer is often highly curable, usually by removing the entire tumor with surgery.

Stage I. This stage is usually a small cancer or tumor that has not grown deeply into nearby tissues. It also has not spread to the lymph nodes or other parts of the body. It is often called early-stage cancer.

Stage II and III. These stages indicate larger cancers or tumors that have grown more deeply into nearby tissue. They may have also spread to lymph nodes but not to other parts of the body.

Stage IV. This stage means that the cancer has spread to other organs or parts of the body. It may also be called advanced or metastatic cancer.

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Agent

A carcinogen is any substance, radionuclide or radiation that is an agent directly involved in the exacerbation of cancer or in the increase of its propagation. Physical carcinogens, such as ultraviolet and ionizing

radiation. Chemical carcinogens, such as asbestos, components of

tobacco smoke, aflatoxin (a food contaminant) and arsenic (a drinking water contaminant).

Biological carcinogens, such as infections from certain viruses, bacteria or parasites; such agents are responsible for almost 22% of cancer deaths in the developing world and 6% in industrialized countries.

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Chemical Benzene Leukemia Polycyclic hydrocarbons (encountered in industrial and car exhaust)

All cancers

Aromatic amines (those in a cigarette) Bladder Occupational exposure to asbestos, chromium, arsenic, nickel, uranium

Many cancers (esp Lung)

Coaltar, X-ray, dyes, heat Skin Food Ascorbate deficiency Leukoplakia ↑ saturated fat Breast, colon Vitamin A deficiency Betel, areca

Oral, esophageal, colorectal

Carcinogens

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Carcinogens

Beef Iron deficiency

Tobacco (either in cigarettes or in its various chewable forms)

Lung, oral

Alcohol Liver Smoked fish (a popular dish in Japan), nitrosamines (food additive)

Stomach

Dietary fiber deficiency Colorectal Virus Hepatitis B and C Liver HIV, cytomegalovirus Kaposi sarcoma, non-

Hodgkin's lymphoma Epstein Barr virus Burkitt lymphoma,

nasopharyngeal carcinoma Human T lymphotropic virus T cell leukemia Human papilloma virus Cervix Parasites Schistosoma Bladder Fungal toxin (aflatoxins), which is produced by the fungus Aspergillus flavus growing on stored grains, nuts and peanut butter

Liver

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Host

AgeAgeing is another fundamental factor for the development of cancer. The incidence of cancer rises dramatically with age, most likely due to a build-up of risks for specific cancers that increase with age. The rising incidence of cancer is partly due to the rise of life expectancy.SexIt is readily observable that some cancers are 'male' (oral, lung, oesophagus, stomach, bladder) and some 'female' (breast, cervix). The difference is attributed to exposure (more men smoke than women) rather than susceptibility. On the other hand, breast cancer is an oestrogen dependent neoplasm, which the male body can not sustain, and cervical cancer is frequently caused by human papillomavirus, which causes similar tumor (papilloma) over male genitalia and perianal region.Obesity was found to be a risk factor for cancer in a study by International Cancer Collaborators, as well as ↓ consumption of fruits and vegetables, physical inactivity and indoor smoke from household fuels.

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'A' blood group stomach carcinoma Down's syndrome Leukemia Other genetic cancers Polyposis coli, retinoblastoma

Genetic factors

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Magnitude of the Problem Worldwide :

The number of new cases of cancer which occurred worldwide in 2012 has been

estimated at about 14,090,000

of which it was projected that 4,653,000 deaths occurred in men and 3,547,000 in

women in the same year.

Among men, the 5 most common sites of cancer diagnosed in 2012 were lung,

prostate, colorectum, stomach, and liver cancer.

While Among women the 5 most common sites diagnosed were breast, colorectum,

lung, cervix, and stomach cancer.

In more developed and less-developed regions of the world, approximately 2,878,000

and 5,323,000 cancer deaths have resulted, respectively.

Around one third of cancer deaths are due to the 5 leading behavioural and dietary

risks: high body mass index, low fruit and vegetable intake, lack of physical activity,

tobacco use, alcohol use.

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Top leading causes of death (CDC, April 27, 2016)

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Different types of cancer show different distribution in different countries

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World Health Organization - Cancer Country Profiles, 2014.

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Cancer Incidence in Iraq

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Annual Report 2014 (Iraq)

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Annual Report 2014 (Iraq)

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Annual Report 2014 (Iraq)

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Prevention

A. Primordial prevention: is prevention of development of cancer’s risk factorsB. Primary prevention1. Control of tobacco and alcohol consumption 2. Maintenance of personal hygiene and being in a monogamous

relationship prevents HPV infection and carcinoma cervix.3. Lessen radiation exposure, esp. reduce unnecessary X-rays done

(which exposes both the patient and the technician to radiation); provide personal protective equipment to workers in radiation plants/ radioactive mines.

4. Lessen occupational exposure to carcinogens through both engineering measures and personal protection.

5. Immunization—Hepatitis B vaccine is now being incorporated in National Immunization Schedule; the human papilloma virus vaccine is now being used against HPV infection.

6. Legislation and surveillance of food additives, drugs and cosmetics.7. Control of air pollution.8. Treatment of precancerous lesions like cervical tears, polyposis,

genital warts, chronic gastritis, chronic cervicitis.

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C. Secondary prevention

A- Cancer registration1. Hospital based.2. Population based

B- Early detection by screening1. Mass screening—Multisite (comprehensive cancer detection

by clinicians by a thorough check-up of whole body). 2. Selective screening of risk groups.

C- TreatmentChemotherapy, Radiation, Surgery, Immunotherapy.

Prevention

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D. Tertiary prevention

1. Rehabilitation (after amputation/ laryngectomy / colostomy/facial surgery).

2. Palliative care. Palliative care is treatment to relieve, rather than cure, symptoms caused by cancer. Palliative care can help people live more comfortably; it is an urgent humanitarian need for people worldwide with cancer and other chronic fatal diseases.

Prevention

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Breast cancer

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− Breast cancer is a kind of cancer that develops from breast cells.

− Breast cancer usually starts off in the inner lining of milk ducts or the lobules

that supply them with milk. A malignant tumor can spread to other parts of the

body. A breast cancer that started off in the lobules is known as lobular

carcinoma, while one that developed from the ducts is called ductal

carcinoma.

− Breast cancer is the most important cause of cancer death among women, and

accounted for an estimated 521,000 deaths worldwide in 2012

− It accounts for 16% of all female cancers and 22.9% of invasive cancers in

women. 18.2% of all cancer deaths worldwide, including both males and

females, are from breast cancer.

Definition

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− Breast cancer rates are much higher in developed nations compared to

developing ones. There are several reasons for this, with possibly life-

expectancy being one of the key factors - breast cancer is more common in

elderly women; women in the richest countries live much longer than those in

the poorest nations. The different lifestyles and eating habits of females in rich

and poor countries are also contributory factors.

− According to the National Cancer Institute, 232,340 female breast cancers and

2,240 male breast cancers are reported in the USA each year, as well as about

39,620 deaths caused by the disease.

Definition

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− A breast lump or thickening that feels different from the surrounding

tissue

− Bloody discharge from the nipple

− Change in the size, shape or appearance of a breast

− Changes to the skin over the breast, such as dimpling

− A newly inverted nipple

− Peeling, scaling or flaking of the pigmented area of skin surrounding

the nipple (areola) or breast skin

− Redness or pitting of the skin over your breast, like the skin of an

orange

Signs and symptoms

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Breast cancer staging

The main stages are:

• Stage 0 is a pre-cancerous or marker condition, either ductal

carcinoma in situ (DCIS) or lobular carcinoma in situ (LCIS).

• Stages 1–3 are within the breast or regional lymph nodes.

• Stage 4 is 'metastatic' cancer that has a less favourable

prognosis since it has escaped into the blood stream.

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Pathophysiology

• Breast cancer, like other cancers, occurs because of an interaction between an environmental (external) factor and a genetically susceptible host. Normal cells divide as many times as needed and stop. They attach to other cells and stay in place in tissues. Cells become cancerous when they lose their ability to stop dividing, to attach to other cells, to stay where they belong, and to die at the proper time.

• Normal cells will commit cell suicide (apoptosis) when they are no longer needed. Until then, they are protected from cell suicide by several protein clusters and pathways. Sometimes the genes along these protective pathways are mutated in a way that turns them permanently "on", rendering the cell incapable of committing suicide when it is no longer needed. This is one of the steps that causes cancer in combination with other mutations.

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Risk factors

Risk factors can be divided into two categories:

1. Modifiable risk factors (things that people can change themselves, such as consumption of alcoholic beverages), and

2. Fixed risk factors (things that cannot be changed, such as age and biological sex).

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Modifiable risk factors

− weight gain after the age of 18 and/or being overweight or

obese (for postmenopausal breast cancer).

− use of menopausal hormone therapy (combined oestrogen

and progestin).

− physical inactivity, and alcohol consumption.

− In addition, recent research indicates that long-term,

heavy smoking may also increase breast cancer risk,

particularly among women who start smoking before their

first pregnancy.

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Fixed (Non-modifiable) risk factors

older age (+50); a personal or family history of breast or ovarian cancer; inherited mutations (genetic alterations) in BRCA1, BRCA2, or other breast cancer susceptibility genes; certain benign breast conditions (such as atypical hyperplasia); a history of ductal or lobular carcinoma in situ; high-dose radiation to the chest at a young age (e.g., for cancer treatment); high breast tissue density (the amount of glandular tissue relative to fatty tissue measured on a mammogram); high bone mineral density (evaluated during screening for osteoporosis); and type 2 diabetes (independent of obesity). Reproductive factors that increase risk include a long menstrual history (menstrual periods that start early and/or end later in life), recent use of oral contraceptives, never having children, having one’s first child after age 30, and high natural levels of sex hormones.

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Prevention of breast cancer

Primary prevention of breast cancer has been attempted via nutritional intervention, involving:

Reduction of energy intake, reduction of the proportion of calories from fat

Increase in fruit and vegetable consumption. Control of weight gain, particularly of post-menopausal

women, would have favourable implications in breast cancer risk.

Breastfeeding women who breastfeed run a lower risk of developing breast cancer compared to other women

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Secondary prevention Screening: • Mammography: The effectiveness of screening by

mammography in women older than 50 years has been demonstrated, and programmes have been established in various countries.

• The effectiveness in women younger than 50 is not yet demonstrated.

• Other screening techniques, including breast self -examination, have not been proven to reduce breast cancer mortality

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The main breast cancer treatment options may include:

1. Radiation therapy (Radiotherapy)

2. Surgery: Lumpectomy, Mastectomy, Sentinel node biopsy, Axillary

lymph node dissection, Breast reconstruction surgery

3. Biological therapy (targeted drug therapy): Trastuzumab

(Herceptin), Lapatinib (Tykerb), Bevacizumab (Avastin), Low dose

aspirin

4. Hormone therapy: Tamoxifen, Aromatase inhibitors, Ovarian

ablation or suppression.

5. Chemotherapy: cytotoxic drugs

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Lung cancer

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Lung cancer

− Lung cancer, also known as lung carcinoma, is a malignant lung

tumor characterized by uncontrolled cell growth in tissues of the lung.

− In 2012 lung cancer was the most frequent cancer in the world as there were

1,824,701 new lung cancer cases, accounting for approximately 13.0 per cent

of the global cancer burden.

− Lung cancer was also the most common cause of cancer death, causing

1,589,800 deaths in 2012.

− Incidence and mortality rates for lung cancer are approximately twice as

high among men as among women.

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Signs and symptoms

Symptoms do not usually occur until the cancer is advanced, and may include:

Respiratory symptoms: coughing, coughing up blood, wheezing, or shortness of breath

Systemic symptoms: weight loss, weakness, fever, or clubbing of the fingernails

Symptoms due to the cancer mass pressing on adjacent structures: chest pain, bone pain, superior vena cava obstruction, or difficulty swallowing

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Types and Staging of Lung Cancer

There are two major types of lung cancer:

1. Non-small cell lung cancer (NSCLC) 

2. Small cell lung cancer (SCLC)

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Types and Staging of Lung Cancer

Non-small cell lung cancer accounts for about 85 % of lung

cancers and includes:

1. Adenocarcinoma, the most common form of lung cancer in

the United States among both men and women;

2. Squamous cell carcinoma, which accounts for 25 % of all

lung cancers;

3. Large cell carcinoma, which accounts for about 10 % of

NSCLC tumors.

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STAGES OF NON-SMALL CELL LUNG CANCER

Stage I: The cancer is located only in the lungs and has not spread to any lymph nodes.Stage II: The cancer is in the lung and nearby lymph nodes.Stage III: Cancer is found in the lung and in the lymph nodes in the middle of the chest, also described as locally advanced disease. Stage III has two subtypes:• If the cancer has spread only to lymph nodes on the same side of the

chest where the cancer started, it is called stage IIIA.• If the cancer has spread to the lymph nodes on the opposite side of the

chest, or above the collar bone, it is called stage IIIB.Stage IV: This is the most advanced stage of lung cancer, and is also described as advanced disease. This is when the cancer has spread to both lungs, to fluid in the area around the lungs, or to another part of the body, such as the liver or other organs.

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Types and Staging of Lung Cancer

2. Small Cell Lung Cancer

Small cell lung cancer accounts for the remaining

15 % of lung cancers in the United States. They tend

to grow more quickly than NSCLC tumors. Usually,

SCLC is more responsive to chemotherapy than

NSCLC.

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STAGES OF SMALL CELL LUNG CANCER

Limited stage: In this stage, cancer is found on one side of the chest,

involving just one part of the lung and nearby lymph nodes.

Extensive stage: In this stage, cancer has spread to other regions of the

chest or other parts of the body.

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Primary Versus Secondary Lung Cancer

Primary lung cancer starts in the lungs. The cancer cells are

abnormal lung cells. Sometimes, people will have cancer travel from

another part of their body or metastasize to their lungs. This is called

secondary lung cancer because the lungs are a secondary site

compared to the original primary location of the cancer.

Example

breast cancer cells which have travelled to the lung are not lung cancer

but rather metastatic breast cancer, and will require treatment

prescribed for breast cancer rather than lung cancer.

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All cells in the body contain the genetic material called deoxyribonucleic acid (DNA). Every time a mature cell divides into two new cells, its DNA is exactly duplicated. The cells are copies of the original cell, identical in every way. In this way our bodies continually replenish themselves. Old cells die off and the next generation replaces them.A cancer begins with an error, or mutation, in a cell’s DNA. DNA mutations can be caused by the normal aging process or through environmental factors, such as cigarette smoke, breathing in asbestos fibres, and to exposure to radon gas.Researchers have found that it takes a series of mutations to create a lung cancer cell. Before becoming fully cancerous, cells can be precancerous, in that they have some mutations but still function normally as lung cells. When a cell with a genetic mutation divides, it passes along its abnormal genes to the two new cells, which then divide into four cells with errors in their DNA and so on. With each new mutation, the lung tissue cell becomes more mutated and may not be as effective in carrying out its function as a lung cell. At a later stage of disease, some cells may travel away from the original tumor and start growing in other parts of the body. This process is call metastasis and the new distant sites are referred to as metastases.

The Genetic Basis of Lung Cancer

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Risk factors

− Cigarette smoking is by far the most important risk factor for lung cancer; 80% of lung cancer deaths are caused by smoking. Risk increases with both quantity and duration of smoking. Cigar and pipe smoking also increase risk.

− Exposure to radon gas released from soil and building materials is estimated to be the second-leading cause of lung cancer.

− occupational or environmental exposure to second-hand smoke, asbestos (particularly among smokers), certain metals (chromium, cadmium, arsenic), some organic chemicals, radiation, air pollution, and diesel exhaust. rubber manufacturing

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Risk factors

− Risk is also probably increased among people with a history of tuberculosis.

− Genetic susceptibility plays a role in the development of lung cancer, especially in those who develop the disease at a young age.

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Prevention of lung cancer

Primary prevention

Control of tobacco smoking (including involuntary smoking)

remains the key strategy for the prevention of lung cancer.

Reduction in exposure to occupational and environmental

carcinogens (in particular indoor pollution and radon).

Increase in consumption of fruits and vegetables.

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Prevention of lung cancer

Secondary prevention

Early detection: Screening with low-dose spiral computed

tomography (LDCT) has been shown to reduce lung cancer

mortality by 20% compared to standard chest x-ray among adults

with at least a 30 pack-year smoking history who were current

smokers or had quit within 15 years.

Treatment: surgery, radiation therapy, chemotherapy, and/or

targeted therapies.

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Prevention of lung cancer

Tertiary prevention

1. Rehabilitation (after thoracotomy, segmentectomy, lobectomy, or pneumonectomy).

2. Palliative care. led to significant improvements in both quality of life and mood.

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Cervical cancer

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Introduction

Cervical cancer is a malignant tumour deriving from cells of the "cervix uteri", which is the lower part, the "neck" of the womb, the female reproductive organ.− The estimated worldwide burden of cervical cancer in 2012 was

approximately 528,000 new cases and 266,000 deaths. − Cervical cancer is a major public health problem in less developed

regions, where about 84 % of cases (445,000) and 86 % of deaths (230,000) occurred in 2012.

− The number of estimated cervical cancer deaths in these regions is third to breast cancer (324,000) and lung cancer (281,000) among women.

− Incidence rates are high (over 30/100,000) in Eastern, Southern, and Middle Africa and Melanesia. Rates are lowest in Australia/New Zealand (5.5), Western Asia (4.4), Middle-East (6.4), Northern American (6.6), and Northern Africa (6.6).

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Introduction

− Incidence and mortality rates have decreased steadily in high-income

countries, but an upturn in incidence had been observed among

young women in a few of these.

− The cervical cancer incidence rate declined by half between 1975

(14.8 per 100,000) and 2012 (6.7 per 100,000) due to the widespread

uptake of screening with the Pap test and removal of precancerous

lesions.

− the cervical cancer death rate in 2012 (2.3 per 100,000) was less

than half that in 1975 (5.6 per 100,000) due to declines in incidence

and the early detection of cancer with the Pap test.

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Signs and symptoms:

Preinvasive cervical lesions often have no symptoms. Once abnormal cervical cells become cancerous and invade nearby tissue, the most common symptoms are:− Abnormal vaginal bleeding, which may start and stop between regular

menstrual periods or occur after sexual intercourse, douching, or a pelvic exam.

− Menstrual bleeding may last longer and be heavier than usual. − Bleeding after menopause and increased vaginal discharge may also be

symptoms.− Symptoms of advanced cervical cancer may include: loss of appetite,

weight loss, fatigue, pelvic pain, back pain, leg pain, swollen legs, heavy vaginal bleeding, bone fractures, and/or (rarely) leakage of urine or feces from the vagina.

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Cervical cancer staging

Stage I. Cancer is confined to the cervix.

Stage II. Cancer at this stage includes the cervix and

uterus, but hasn't spread to the pelvic wall or the lower

portion of the vagina.

Stage III. Cancer at this stage has moved beyond the cervix

and uterus to the pelvic wall or the lower portion of the

vagina.

Stage IV. At this stage, cancer has spread to nearby organs,

such as the bladder or rectum, or it has spread to other

areas of the body, such as the lungs, liver or bones.

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Risk factors

− Persistent infection with certain types of human papillomavirus (HPV) (16,18,31,33).

− While women who begin having sex at an early age or who have had many sexual partners are at increased risk for HPV infection and cervical cancer, a woman may be infected with HPV even if she has had only one sexual partner. In fact, HPV infections are common in healthy women and only rarely cause cervical cancer.

− Both persistence of HPV infection and progression to cancer may be influenced by many factors, including a suppressed immune system, a high number of childbirths, and cigarette smoking.

− Long-term use of oral contraceptives (birth control pills) is also associated with increased risk of cervical cancer.

− Multiple pregnancies (seven or more full-term pregnancies).

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Prevention of cervical cancer

Primary prevention

• Health promotion. Safe sexual practices, improvement of

hygiene.

• Specific protection. The HPV vaccine is a bivalent vaccine

(against two strains that cause 70% of cervical cancer) which is

injected IM in three doses over a period of six months.

• Vaccination is recommended for use in girls 11 to 12 years of age,

but may be given as young as age 9 and up to age 26.

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Prevention of cervical cancer

Secondary prevention

• Screening can prevent cervical cancer by detecting precancerous

lesions that can be treated so they do not progress to cancer.

• The Pap test is a simple procedure in which a small sample of cells

is collected from the cervix and examined under a microscope.

• HPV tests, which detect HPV infections associated with cervical

cancer.

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Prevention of cervical cancer

Secondary prevention

• Treatment: Precancerous cervical lesions may be treated with a

loop electrosurgical excision procedure (LEEP), which removes

abnormal tissue with a wire loop heated by electric current;

cryotherapy (the destruction of cells by extreme cold); laser

ablation (removal of tissue); or conization (the removal of a cone-

shaped piece of tissue containing the abnormal tissue).

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Colorectal cancer

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Definition

• Colorectal cancer is cancer that starts in the colon or rectum. • Colon cancer is cancer of the large intestine (colon), the lower

part of digestive system. Rectal cancer is cancer of the last several inches of the colon. Together, they're often referred to as colorectal cancers.

• Cancers of the colon and rectum are rare in developing countries, but are the second most frequent malignancy in affluent societies; over 940,000 cases occur annually worldwide. With increasing industrialization and improving economy with consequent changes in lifestyle in many of the developing countries, the incidence may rise.

• The majority (55 per cent) of cases of colorectal cancer occur in high-income regions of the world, and geographical patterns are very similar in men and women. Generally, rates are slightly higher among men than women. (GLOBOCAN 2012).

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Definition

• Cancers of the colon and rectum accounted in 2012 for an estimated 1,361,000 new cases and 694,000 deaths worldwide.

• As of 2012, it is the second most common cause of cancer in women (9.2% of diagnoses) and the third most common in men (10.0%) with it being the fourth most common cause of cancer death after lung, stomach, and liver cancer.

• Incidence rates have generally been decreasing since the mid-1980s due to both changes in risk factors (e.g., decreased smoking, increased use of non-steroidal anti-inflammatory drugs) and the uptake of screening among adults 50 years of age and older.

• From 2008 to 2012, incidence rates declined by 4.5% per year among adults 50 years of age and older, but increased by 1.8% per year among those younger than age 50.

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Signs and symptoms

• A change in the bowel habits, including diarrhoea or

constipation or a change in the consistency of the stool,

that lasts longer than four weeks

• Rectal bleeding or blood in the stool

• Persistent abdominal discomfort, such as cramps, gas or

pain

• A feeling that bowel doesn't empty completely

• Weakness or fatigue

• Unexplained weight loss

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Stages of colon cancer

Stage I. Your cancer has grown through the superficial lining (mucosa) of the

colon or rectum but hasn't spread beyond the colon wall or rectum.

Stage II. Your cancer has grown into or through the wall of the colon or rectum

but hasn't spread to nearby lymph nodes.

Stage III. Your cancer has invaded nearby lymph nodes but isn't affecting

other parts of your body yet.

Stage IV. Your cancer has spread to distant sites, such as other organs — for

instance, to your liver or lung.

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Risk factors

Older age. The great majority of people diagnosed with colon cancer are older than 50. Colon

cancer can occur in younger people, but it occurs much less frequently.

African-American race. African-Americans have a greater risk of colon cancer than do

people of other races.

A personal history of colorectal cancer or polyps. If you've already had colon cancer or

adenomatous polyps, you have a greater risk of colon cancer in the future.

Inflammatory intestinal conditions. Chronic inflammatory diseases of the colon, such as

ulcerative colitis and Crohn's disease, can increase your risk of colon cancer.

Inherited syndromes that increase colon cancer risk. Genetic syndromes passed through

generations of your family can increase your risk of colon cancer. These syndromes include

familial adenomatous polyposis and hereditary non-polyposis colorectal cancer, which is also

known as Lynch syndrome.

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Risk factors

Family history of colon cancer. You're more likely to develop colon cancer if you have a

parent, sibling or child with the disease. If more than one family member has colon cancer or

rectal cancer, your risk is even greater.

Low-fiber, high-fat diet. Colon cancer and rectal cancer may be associated with a diet low in

fiber and high in fat and calories. Research in this area has had mixed results. Some studies

have found an increased risk of colon cancer in people who eat diets high in red meat and

processed meat.

A sedentary lifestyle. If you're inactive, you're more likely to develop colon cancer. Getting

regular physical activity may reduce your risk of colon cancer.

Diabetes. People with diabetes and insulin resistance may have an increased risk of colon

cancer.

Obesity. People who are obese have an increased risk of colon cancer and an increased risk

of dying of colon cancer when compared with people considered normal weight.

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Risk factors

Smoking. People who smoke may have an increased risk of colon cancer.

Alcohol. Heavy use of alcohol may increase your risk of colon cancer.

Radiation therapy for cancer. Radiation therapy directed at the abdomen to treat previous

cancers may increase the risk of colon cancer.

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Prevention

Primary prevention:

• Increased physical activity.

• Avoidance of overweight and obesity,

• Reduced alcohol drinking.

• Quitting smoking.

• While aspirin use could prevent colorectal cancer as well, its use is

not routinely recommended because of its spectrum of side effects.

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Prevention

Secondary prevention:

• Early detection: Beginning at the age of 50, men and women who are at

average risk for developing colorectal cancer should begin screening.

• either annual faecal occult blood testing or one colonoscopic

examination which does not need to be repeated in 10 years if results

are normal.

• Randomized trials have also demonstrated the efficacy of

sigmoidoscopy in reducing colorectal cancer mortality, primarily for

the distal colon.

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Prevention

Secondary prevention:• Treatment: Surgery is the most common treatment for colorectal cancers that

have not spread. A permanent colostomy (creation of an abdominal opening for

elimination of body waste) is not usually required for rectal cancer and is rarely

necessary for colon cancer.

• Chemotherapy alone, or in combination with radiation, is given before

(neoadjuvant) or after (adjuvant).

• Supportive (palliative) care: Palliative care is provided by a team of doctors,

nurses and other specially trained professionals.

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Prostate cancer

78

Introduction

− The prostate is a gland found only in men. It’s part of the reproductive system and helps to make semen. It’s located in front of the rectum and under the bladder. A healthy prostate gland is about the size of a walnut.

− Prostate cancer starts in the cells of the prostate.− Prostate cancer is one of the most common types of cancer in men.

− Prostate cancer is the second most common cancer and the fifth leading cause of

death from cancer in men worldwide with an estimated 1,111,000 newly diagnosed

cases and 307,000 deaths in 2012.

− Black men in the US and Caribbean men of African descent have the highest

documented prostate cancer incidence rates in the world.

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Introduction

− An estimated 180,890 new cases of prostate cancer will occur in the US during 2016. Prostate cancer is the most frequently diagnosed cancer in men aside from skin cancer. For reasons that remain unclear, the risk of prostate cancer is 70% higher in blacks than in non-Hispanic whites.

− Almost 70 per cent of the cases (759,000) occurred in more developed regions. It is the most common malignant neoplasm in men from Australia/ New Zealand (111.6/100,000), North America (97.2/100,000), and Western Europe (94.9/100,000).

− The incidence is 69.5/100,000 in high-income regions and 14.5/100,000 in low-

and middle-income regions..

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Signs and symptoms

Prostate cancer may cause no signs or symptoms in its early stages.

Prostate cancer that is more advanced may cause signs and symptoms such as: Trouble urinating Decreased force in the stream of urine Blood in the semen Discomfort in the pelvic area Bone pain Erectile dysfunction

81

Prostate cancer staging Whitmore-Jewett staging system:

In this system, the tumor is classified by letters (A to D). 

• Stage A: Indicates that the cancer cannot be felt or seen by the naked

eye  

• Stage B: Indicates that the cancer is not detectable by the presence of

a tumour 

• Stage C: Indicates that the cancer has spread to surrounding tissues

and vesicles of the prostate 

• Stage D: Indicates that the cancer has spread to bones and organs

throughout the body

82

Risk factors:

The only well-established risk factors for prostate cancer are increasing age (+50).

In the United States it is more common in the African American population than the White American population.

Having a first degree relative with the disease increases the risk 2 to 3 fold. Genetic studies suggest that strong familial predisposition may be responsible for 5%-10% of prostate cancers. Inherited conditions associated with increased risk include Lynch syndrome and BRCA1 and BRCA2 mutations.

Studies suggest that obesity and smoking do not increase the overall risk of developing prostate cancer, but may increase risk of developing aggressive/ fatal disease.

83

Prevention

Primary prevention Lowering prostate cancer risk

o Choose a healthy diet full of fruits and vegetables.o Choose healthy foods over supplements. o Exercise most days of the week.o Maintain a healthy weight.

The chemoprevention of prostate cancer is an active area of research. Two drugs of interest, finasteride and dutasteride, reduce the amount of certain male hormones in the body and are approved to treat the symptoms of benign prostatic hyperplasia.

84

Prevention

Secondary prevention Early detection:

Screening for prostate cancer can be done with: o Prostate-Specific Antigen (PSA) blood test.o Digital Rectal Exam (DRE)Choose healthy foods over

supplements. Management:

surgery (open, laparoscopic, or robotic-assisted), external beam radiation, or radioactive seed implants (brachytherapy). Hormonal therapy may be used along with surgery or radiation therapy in more advanced cases.

Palliative care.

85

Stomach cancer

86

Introduction

The stomach is an organ between the oesophagus and the small intestine. It mixes food with stomach acid and helps digest protein.

Stomach cancer, also known as gastric cancer, is cancer developing from the lining of the stomach.

Stomach cancer mostly affects older people - two-thirds of people who have it are over age 65.

About one million new cases of stomach cancer were estimated to have occurred in 2012 (6.8% of the total), making it currently the fifth most common malignancy in the world, behind cancers of the lung, breast, colorectum and prostate. More than 70% (677,000) of cases occur in developing countries (456,000 in men, 221,000 in women), and half the world total occurs in Eastern Asia.

87

Introduction

Highest rates (over 40 per 100,000 in males) are reported from Japan, China, the former USSR, and certain countries in Latin America. And The lowest rates (< 15 per 100,000) are seen in North America (specifically, its white population), India, the Philippines, most African countries, some countries in Western Europe, and Australia.

stomach cancer is the third most common cause of cancer death worldwide (723,000 deaths in 2012, 8.9 per cent) in 2012. This marks a substantive decrease in incidence since 1975 when stomach cancer was the most common neoplasm worldwide.

88

Signs and symptoms of stomach cancer

Fatigue

Feeling bloated after eating

Feeling full after eating small amounts of food

Heartburn that is severe and persistent

Indigestion that is severe and unrelenting

Nausea that is persistent and unexplained

Stomach pain

Vomiting that is persistent

Weight loss that is unintentional

89

Risk factors

A diet high in salty and smoked foods A diet low in fruits and vegetables Eating foods contaminated with aflatoxin fungus Family history of stomach cancer Infection with Helicobacter pylori Long-term stomach inflammation Pernicious anaemia Smoking Stomach polyps The latest research indicated that Alcohol and

Processed Meats May Raise Stomach Cancer Risk (04/21/2016, Health Day)

90

Prevention

Primary prevention:A. Dietary means is feasible by encouraging high-risk populations to:

• Eat more fruits and vegetables.• Decrease consumption of processed meats, smoked and

salt preserved foods. • Stop smoking and alcohol.

B. Eradication of H. pylori infection, particularly in childhood and adolescence, and by avoiding mother to child transmission, at least in those who are Asian.

91

Prevention

Secondary prevention:

Screening and early detection of stomach cancer have been

developed in Japan with the use of X-ray photofluorography to

identify early lesions, followed by gastroscopy.

Treatment for stomach cancer may include surgery,

chemotherapy, and/or radiation therapy. New treatment

approaches such as biological therapy and improved ways of using

current methods are being studied in clinical trials.

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References

Parikshit, S. Community Medicine: A Students Manual, First Edition: 2015, Jaypee Brothers Medical Publishers, Bhotahity, Kathmandu, Nepal, pp: 337-341.

Roger, D et al. Oxford Textbook of Global Public Health, Sixth Edition, 2015, Oxford University Press, USA, pp: 923-991

Park, K. Textbook of Preventive & Social Medicine. 23th edition. India: M/s Banarsidas Bhanot; 2015, pp: 381-390.

RajVir, B. Textbook of Public Health & Community Medicine, 2009,1st edition. India, Department of Community Medicine in Collaboration with WHO. pp: 1221-1231.

Cancer Facts & Figures 2016. the Legal department of the American Cancer Society, 250 Williams Street, NW, Atlanta, GA 30303-1002.

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References

Websites:

www.who.int/mediacentre/factsheets/fs297/en/

www.cdc.gov/nchs/fastats/leading-causes-of-death.htm

https://en.wikipedia.org/wiki/Cancer

www.webmd.com/cancer/

www.cancer.org/

www.mayoclinic.org/diseases.../cancer/.../con-2003237

www.nhs.uk/conditions/cancer/Pages/Introduction.aspx

http://globocan.iarc.fr/Default.aspx