Colorectal Cancer

Colorectal cancer develops in the colon (large intestine) or the rectum (the passage connecting the colon to the anus). It usually begins as small growths called polyps that may become cancerous over time.

It is one of the most common and preventable cancers, as polyps can be detected and removed during screening tests such as colonoscopy.

Early colorectal cancer often shows no symptoms. As the disease progresses, symptoms may include:

• Changes in bowel habits (diarrhea, constipation, or narrow stools)
• Blood in stools or rectal bleeding
• Persistent abdominal pain, cramps, or bloating
• Unexplained weight loss
• Weakness and fatigue due to anemia
• Feeling that the bowel does not empty completely
• Nausea and vomiting in advanced stages

Colorectal cancer is staged based on how far it has spread:

• Stage I: Cancer is limited to the inner lining of the colon or rectum.
• Stage II: Cancer has grown into the muscle layer or through the colon wall.
• Stage III: Cancer has spread to nearby lymph nodes.
• Stage IV: Cancer has spread to distant organs like the liver, lungs, or bones.

Surgery, chemotherapy, radiation therapy, targeted therapy, and immunotherapy depending on stage.

Several factors can increase the risk of colorectal cancer:

• Age: Risk increases after age 50.
• Family history: Having relatives with colorectal cancer or polyps.
• Inherited syndromes: Conditions like Lynch syndrome and Familial Adenomatous Polyposis (FAP).
• Diet: High intake of red or processed meats, low-fiber diet.
• Lifestyle factors: Obesity, lack of exercise, smoking, and heavy alcohol consumption.
• Medical conditions: Inflammatory bowel diseases like Crohn’s disease or ulcerative colitis.
• Type 2 diabetes: Associated with higher colorectal cancer risk.

Colorectal cancer can often be prevented with lifestyle changes and regular screenings:

• Get screened regularly (colonoscopy, stool tests) after age 45 or earlier if at high risk.
• Eat a fiber-rich diet with fruits, vegetables, and whole grains.
• Limit red and processed meats.
• Stay physically active and maintain a healthy weight.
• Quit smoking and reduce alcohol intake.
• Manage chronic conditions such as diabetes or inflammatory bowel disease.

Colorectal cancer is the third most common cancer worldwide.

• Globally, there are over 1.9 million new cases diagnosed annually.
• In India, colorectal cancer accounts for ~5% of all cancers, with rising incidence in urban populations.
• Men have a slightly higher risk than women.
• The 5-year survival rate is about 65% overall, but it exceeds 90% when detected early.