Discuss the management of colonic polyps

Discuss the management of colonic polypsByDr Kabiru SalisuSurgery dept. AKTH

OutlineIntroductionClassification of colonic polypAetiopathogenesisCommon polypsDiagnosisTreatment ComplicationConclusionReference

Introduction The term polyp is a clinical description of any elevated tumourIt covers a variety of histologically different tumoursA colorectal polyp is any projecting mass that produces an elevation of the mucosa

Polyps can occur singly, synchronously in small numbers or as part of a polyposis syndromeIn familial adenomatous polyposis (FAP), more than 100 adenomas are presentThey are important because they have significant malignant potential resulting in colonic ca which is the 2nd leading cause of death

Relevant Anatomy

The large intestine extends from the ileocecal valve to the anus. It is divided anatomically and functionally into the colon, rectum, and anal canal. The wall of the colon and rectum comprise five distinct layers: mucosa, submucosa, inner circular muscle, outer longitudinal muscle, and serosa. In the colon, the outer longitudinal muscle is separated into three teniae coli, which converge proximally at the appendix and distally at the rectum, where the outer longitudinal muscle layer is circumferential. In the distal rectum, the inner smooth-muscle layer coalesces to form the internal anal sphincter. The intraperitoneal colon and proximal one third of the rectum are covered by serosa; the mid and lower rectum lack serosa.Colon Landmarks5

The fairly thick mucosa of the large intestine has deep crypts, but there are no villiIts surface epithelium consists of columnar absorptive cells with a striated border and many goblet cells

Classification of colonic polyps

Aetiopathogesis Risk FactorsAge 50 or older overweight smoker high-fatlow-fiber dietSedentary life-style family history of colon polyps or colon cancer.

Adenomacarcinoma sequenceThe Fearon-Vogelstein adenomacarcinoma multistep model of colorectal neoplasia represents one of the best-known models of carcinogenesisMost colorectal cancers develop from adenomasThere is an adenoma-cancer sequence which probably takes 5-15 years.

APC- ADENEMATOUS POLYPOSIS COLI GENE, DCC- deleted colon cancer gene10

Adenomas The most common polyps are the adenomas which may be- Tubular (75 %),- Tubulo-villous (15 %) - villous (10%)The prevalence - 34 % in 50- 60 year 40-60 % in 75 and overAbout 50 % occur in the rectum and sigmoid About 50% of patients have more than one tumour

The most common polyps are the adenomas which may betubular (75 %), tubulo-villous (15 %) or villous (10%) inhistology.The prevalence of colorectal adenoma in necropsy specimensin advanced communities is quite high ( about 34 % in 50-60 year -olds and 40-60 % in those aged 75 and over). About 50 %of adenomas occur in the rectum and sigmoid and about 50%of patients have more than one tumour.12

The malignant propensity of an adenoma depends on its 'Sizepathological type degree of epithelial dysplasia.size 1 % if the diameter is < lcm 10% if the diameter is l-2cm 50% if the diameter is > 2cm

Pathological type 5 % of tubular adenomas 20% of tubulovillous 50% of villous adenomas may become cancerous

Adenomas with a high degree of epithelial dysplasia and those that are sessile are more likely to become malignant.

Hamartomatous polyps1- PeutzJeghers polyps may occur in the colon as either solitary or multiple lesions. 2- Juvenile polyps may occur as multiple lesions in the colon often associated with a congenital defect such as a malrotation or Meckels diverticulum. They have minimal malignant potential and are only removed if they are causing troublesome pain, bleeding or hypoproteinaemia

Familial Adenomatous Polyposis (FAP) It is well known that certain heritable conditions confer a very high risk of colorectal cancer FAP is a rare hereditary disease in which the large intestine, especially the rectum and sigmoid, contains more than 100 sessile and/or pedunculated polyps of varying sizes and shapes.

These inherited syndromes are grouped under FAP. They includea) Familial adenomatosis colib) Gardners syndromec) Turcot s syndromed) Oldfields syndrome

a) Familial adenomatosis coli

The genetic abnormality in FAP is a mutation in the APC gene, located on chromosome 5qThe main symptom are Diarrhoeapassage of mucus and or blood in stools lower abdominal painSymptoms starts around the age of 20yrs, untreated patient develop cancer after 15yrs and died at 42yrs

b) Gardners syndrome

Some patients, in addition to polyposis haveMultiple sebaceous and dermoid cysts, Desmoid tumoursOsteomata of the skull and mandible papillary carcinoma of the thyroid,Hepatoblastoma leukaemia, Adenomata of the stomach and duodenumMedulloblastoma

C- Turcot Syndrome- fewer colonic polyps with intracranial tumors.

D- Oldfields Syndrome- polyposis, carcinoma of colon, sebaceous cyst

Diagnosis

History 1- assymptomatic 2- lower GI bleeding haematochesia or malaena 3- Mucoid Diarrhea esp. in villous adenoma 4- change in bowel habit 5- intestinal obstruction ( abd. Pain, constipation and vomiting )6- Rectal fullness, tenesmuss, pellat like stools, feeling of incomplete emptying7- Intussuception, anal protrution or prolapse8- other assocd. anomaly

Examination Features anaemiaDehydrationAbd. Swellings / destentions/ palpable massesDRE Anal protrusions, palpable masses, frank blood or malaena Other associated anomalies eg osteomas, sebacious cyst, thyroid swelling

Investigations 1- Stool occult blood FOBT or FIT2- double contrast barium enaema3- proctoscopy, segmoidoscopy or colonoscopy4- abdominal CT and MRI5- DNA testing eg APC gene, DCC

Screening policy1. All members of the family of patient with FAP should be examined at the age of 1012 years, repeat every 12 years2. Most of those who are going to get polyps will have them at 20 and these require operation3. If there are no polyps at 20, continue with 5-yearly examination until age 50; if there are still no polyps there is probably no inherited gene

Examination of blood relatives, including cousins, nephews and nieces, is essential and a family tree should be constructed and a register of affected families maintained.25

Treatment 1- Polypectomy - Endoscopic for sessile and pedenculated polyps - Laparoscopic - open- large polyp2 - Resection and anastomosis for multiple polyps3- Total colectomy + mucosal protectomy and ileo anal J- pouch anastomosis for FAP

Conclusions Colonic ca is lethal tumuor in which polyps are the commonest pre-cancerous conditionsEarly detection of polyps, screening and surveillance of people at risk will go along way in preventing development of colonic cancer

References Russell, R.C.G. et al (2004) Bailey & Loves short practice of Surgery, 65;1177- 1179 24th edition. Edward Arnold Publishers LtdBadoe E. A et al ; principles and practice of surgery including pathology in the tropics 38; 719- 122 4th editionChalse B. F. et al; Adenocarsinoma and colonic polyps, Schwatzs principles of surgery 8th edition access medicinePeter J. M & williams C.W; colorectal tumour, morris oxford test book of surgery 26.3 2nd edition, oxford pressCourtney M. T. etal, Benign colonic tumour; Sabiston test book of surgery, 16th edition

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