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Colorectal polyps and genetic polyposis syndromes
Tumor is a lesion that is presented by extra- tissue and is based on genetic abnormalities in colonocytes leading to loss of
control over cell growth and differentiation. Tumors can be benign and malignant.
Polyps and polyposis syndromes. The definition of polyp is not clear at all. Presently, only epithelial glands excrescence,
which rises above mucosa, is called true polyp. Clinically, the two morphologic types of polyps are pedunculated and sessile.
Etiology and pathogenesis. That’s difficult to consider accurate incidence of colorectal polyps, because patients with polyps
usually have no symptoms. Often polyps are found by chance, when patients have complains (discomfort and pain in anus,
flatulency, bleeding from anus) typical for other diseases (hemorrhoid, anal fistula, anal fissure, colitis, colon cancer ecc.). So,
real frequency of polyps can be identified only by screening examinations or autopsy. Some studies show that incidents of
colorectal adenomas is 2,5% to 7,5% among patients checked by rigid proctosigmoidoscopy. Sure, real incidents is much higher
because authors didn’t check proximal parts of colon (50% of colorectal adenomas are localized there).
Etiology of colorectal polyps is not clear. Virus theory is proved only on animals. The environment (factories, big cities) and
life-stile (sedentary lifestyle, excessive alcohol, diet high in saturated fat) influence on frequency of colorectal polyps is evident.
There is identified that citizens of economically developed countries eat more animal’s fat and less cellulose. That’s why content
of colon is full of bilious acids (which turn into carcinogenic metabolites) and has small amount of cellulose (that speed up
movement of colon content). Long contact between colon and carciongenic agents increases possibility of polyp appearance.
Most of patients with benign polyps have no symptoms, and these polyps can be identified only during colonoscopy. If there is
big villous adenoma (2-3cm) patients can admit bleeding, stomachache, and anal pain, diarrhea or anal itch. If villous adenoma
is huge patients can have disproteinemia, anemia ecc. Big adenomas also can become the reason of intestinal obstruction. Villous
adenomas have substantial risk of malignancy – 40%.
Diagnosis. If patient has one of said symptoms first of all he or she should be checked by digital examination and rigid
10cm of rectum under anal verge can be checked by digital examination. This examination is primary and obligatory. It also
should be always performed before rigid sigmoidoscopy, because this method is very informative in case of other diseases of
rectum (hemorrhoid, fistula, fissure, cancer), of prostate (adenoma, cancer).
Rigid sigmoidoscopy requires special preparation by enemas or laxatives (forlax ecc.). This method detects most of colon polyps
(since 50% of them localized in rectum and sigmoid colon). If any polyps were identified in rectum or sigmoid colon, other parts
of colon and also stomach should be checked by colonoscopy or barium enema and gastroscopy.
Barium enema is important examination, which allows identifying most of polyps bigger then 1cm, smaller polyps are detected
more seldom. So, there is better to perform colonoscopy, which detects even smaller then 0,5mm polyps, as a screening
Presently, there is no medication treatment of polyps or villous adenomas.
All of them can be removed only by colonoscopy or surgical operation.
There are the most common methods of polyps and villous adenomas treatment.
- Transanal excision of adenomas
- Colonoscopic plypectomy
- Transanal endoscopic microsurgery (TEM) excision
- Transanal rectum resection (circumferential villous adenomas)
- Colotomy and polypectomy
Further results of treatment.
Recurrence of polyps and cancer evolution can occur after operation, the highest risk is during first 2 years. That’s why patients
with benign polyps should be checked in 1,5-2 months after operation, then in 6 months and in 1 year and after this, every year.
If removed polyp was identified as malignant, patient should be checked every month (during first year after operation), every
3 months (during second year after operation), and afterwards every 6 months.
First two years, the risk of removed benign polyp recurrence is 13%, appearance of new polyps occurs in 7% of patients. The
risk of adenomas and villous adenomas recurrence is much higher 8% and 25% respectively.
The recurrence is an indication for exigent operation.