Formation and Stages of Colon Cancer

Colon cancer is a serious type of cancer that develops as a result of the uncontrolled proliferation of the mucosa cells in the large intestine and rectum. 95% of cases develop from adenomatous polyps and are mostly seen in the left colon (72%). Genetically inherited Lynch syndrome and familial adenomatous polyposis account for 5% of cases. Risk factors include advanced age (90% of cases are over 50 years old), excessive red meat consumption, smoking, and obesity. Patients with a history of inflammatory bowel disease have a 28% increased risk after 20 years. Colonoscopy is the gold standard for diagnosis, and the risk of malignancy increases with polyp size: 15% for polyps under 1 cm, 35% for polyps over 2 cm. Contrast-enhanced CT (92% accuracy), MRI for liver metastases (97% sensitivity), and PET-CT for distant metastases (94% sensitivity) are used for staging.

Surgical Treatment Approaches

According to NCCN guidelines, surgical treatment is planned based on the stage of the disease. In early stages, laparoscopic resection is preferred (98% success rate). In advanced stages, open surgery with removal of at least 12 lymph nodes is performed, and D3 dissection increases 5-year survival by 12.5%. Right hemicolectomy has a low risk of complications for right-sided tumours. In rectal cancer, the neoadjuvant FOLFOX-RT protocol provides a 43% complete response. Patients return to daily life within 4 weeks after an average 6-day hospital stay. The main complications are wound infection (8.5%) and anastomotic leakage (4.2%). Survival rates vary by stage: Stage I 92%, Stage II 73-84%, Stage III 44-83%. In Stage IV, median survival is 28 months with FOLFIRI chemotherapy.