Colon cancer is one of the leading cancers worldwide apart from breast cancer and lung cancer. This form of cancer typically starts as small, benign clumps of cells called polyps that form on the inside of the colon

Risk Factors

  1. Diet: increased red meat consumption and a high fat diet increases the risk of colon cancer.
  2. Post cholecystectomy increases risk.
  3. Inflammatory bowel diseases- Ulcerative colitis> Crohns disease increases risk,
  4. Familial conditions like adenomatous polyps , hamartomas and HPNCC increases risk of colorectal cancer.

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However, factors such as hormone replacement therapy (estrogen), COX inhibitors, metformin, and diets rich in fiber and calcium have protective effects.

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Pre-cancerous lesions

1. Familial Adenomatous Polyposis (FAP)

It is an autosomal dominant condition characterized by reduced expression of the APC gene, which leads to increased expression of beta-catenin. Polyps typically develop in the second decade of life. If left untreated, these polyps have a nearly 100% risk of progressing to colorectal cancer, typically by the age of 40. Hence, total proctocolectomy with ileal pouch anal-anastomosis (IPAA) is advised.

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2. Attenuated FAP

Attenuated Familial Adenomatous Polyposis (AFAP) is a milder variant of the classic Familial Adenomatous Polyposis (FAP) and thus, has lower risk of developing colorectal cancer. In AFAP, fewer than 100 adenomatous polyps are present, typically ranging from 10 to 100. Individuals with AFAP generally develop polyps later, with the onset commonly occurring in the 4th decade of life.

3. Hamartamous Polyp

Peutz-Jegher syndrome:

Peutz-Jeghers syndrome (PJS) is an autosomal dominant genetic disorder linked to mutations in the STK11 (LKB1) gene on chromosome 19. This syndrome is characterized by the development of hamartomatous polyps throughout the gastrointestinal (GI) tract, most commonly found in the duodenum and jejunum, with less frequent occurrence in the colon. These polyps possess a distinctive fibrovascular core that creates an arborizing structure resembling a Christmas tree pattern. Early diagnosis and management are essential, involving regular surveillance through endoscopic examinations and imaging to detect and remove polyps before they cause complications like bowel obstruction or intussusception.

Juvenile Polyposis:

A diagnosis is typically made when there are more than five polyps present in the GI tract. JPS is associated with mutations in genes such as SMAD4 and BMPR1A. This condition typically manifests before the age of 40 years.

4. HPNCC