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Immunology of

NeoplasiaPersons with congenital immunodeficiencies -increased risk (200 times normal) formalignancies, Immune surveillance must playsome role in preventing neoplasia.

Viral and chemical-induced cancers in

animals associated with "tumor-specificantigens" This is equivocal in humans. Suchantigens could evoke host defenses in theform of sensitized cytotoxic T lymphcytes,natural killer (NK) cells, macrophages. Such

antigens evoke humoral immunity (antibodyformation), but could "block" antigens andprevent recognition and attack throughcellular immunity.

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Diagnostic Methods for

NeoplasiaHistory and Physical Examination

What the health care worker learns from

talking to the patient and through directexamination may give clues to the

presence of a neoplasm. Signs and

symptoms such as weight loss, fatigue,

and pain may be present. A mass maybe palpable or visible.

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Radiographic

TechniquesThe use of plain films (x-rays),computed tomography (CT), magneticresonance imaging (MRI),mammography, and ultrasonography(US) may be very helpful to detect thepresence and location of mass lesions.The findings from these methods may

aid in staging and determination oftherapy.

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Laboratory AnalysesGeneral findings such as anemia, enzymeabnormalities (increased alkalinephosphatase), hematuria or positive stooloccult blood helpful to suggest further

workup. More specific testing, such asmeasurement of p sa levels, may help todetermine the presence of specificneoplasms, but such tests are not perfectscreening tools in a general population.

Detection of specific genes (such as BRCA-1for breast cancer) suggest an increased riskfor some malignancies

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Diagnosis of Neoplasia

Cytology: fastest and simplest with leastmorbidtity, but yield few cells. Techniquesinclude fine needle aspiration, brushings

through endoscope, tapping of fluidcollections through needle, direct scrapingssuch as pap smear.

Biopsy: take a bite of tissue, either a smallpiece through endoscope or larger piece as

excision. more preparation and skill required,the potential for complications greater, butmore diagnostic tissue obtained.

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Cytology

Methods that sample cells can besimple and cost-effective and minimallyinvasive. A good example is the Papsmear for diagnosis of cervicaldysplasias and neoplasms. Cellsexfoliated into body fluids may also beexamined. Fine needle aspiration (FNA)

can be used to sample a variety ofmass lesions

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Tissue Biopsy and

SurgeryMethods that sample small pieces of tissue(biopsy) from a particular site, often viaendoscopic techniques (such as

colonoscopy, upper endoscopy, orbronchoscopy) can often yield a specificdiagnosis of malignancy. At surgery, portionsof an organ or tissue can be sampled, or thediseased tissue(s) removed and examined in

surgical pathology to determine the stage andgrade of the neoplasm

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Autopsy

Sometimes neoplasms are not detected orcompletely diagnosed during life. Theautopsy serves as a means of quality

assurance for clinical diagnostic methods, asa way of confirming diagnoses helpful inestablishing risks for family members, as ameans for gathering statistics for decisionmaking about how to approach diagnosis and

treatment of neoplasms, and to providematerial for future research

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Autopsy: some neoplasms are

discovered only at autopsy, either

because they had not yet manifested aneffect, because diagnostic techniques

did not work, or because the patient

died before a diagnosis could be

obtained

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Limitations of diagnosis:

Sampling error: not all neoplasms areuniform, material obtained may be thedesmoplastic reaction, area of necrosis,

inflammation around neoplasm, or notrepresentative of the neoplasm.

Improper handling: allowing the sample todry, crushing material, using wrong fixative,delay in sending to laboratory.

Lack of correlation betweeen histologicappearance and actual biologic behavior ofthe neoplasm

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Adjuncts to histologic

diagnosis:Flow cytometry: more aneuploid tumorsworse prognosis, still an experimentaltechnique.

DNA probes recognize oncogenes or clonalgene rearrangements

. Immunohistochemistry identify tumor-specific products or markers (such as p s a,common leukocyte antigen, keratin).

Tumor markers in serum carcinoembryonicantigen (CEA), alpha-fetoprotein (AFP),human chorionic gonadotropin (HCG),

rostatic acid hos hatase PAP .

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They are not all that specific or

sensitive, particularly when applied as

screening tests to a general population

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Treatment for NeoplasiaSurgery: the most effective method, but not all

primary sites are accessible or resectablewith a clear margin. Once metastasis hasoccurred, surgery is no longer primary

curative therapy.Radiation: effectiveness depends uponradiosensitivty of tumor and the body's abilityto tolerate the dose without serious sequelaefrom necrosis, fibrosis, or radiation sickness.

Chemotherapy: effectiveness depends uponability of the drug to selectively poison theneoplastic cells and not normal cells.

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om nat on

chemotherapy

(multiple drugs)allows lower doses of each drug withpotentially less tumor resistance. Someneoplasms -hormonal therapy (estrogensinhibit prostatic adenocarcinoma,antiestrogen therapy inhibits breastadenocarcinoma).

Immunotherapy: either tries to promote thebody's own immune surveillance (activating T

lymphocytes) or tries to direct antibodiesagainst tumor antigens.

Physical agents: hyperthermia ,cryotherapyattempt to selectively kill more thermally

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The problem with all treatments other than

surgery is that they are never 100%

selective for the neoplastic cells, and

normal cells are injured.

Patients with a positive attitude or who

have something to live for and have

emotional support from family, friends, or a

caring physician will tend to do better withtreatment and/or live longer.