Rectal Cancer

Rectal cancer is the formation of malignant tumors in the inner lining of the last section of the large intestine, ending at the anus. Due to their similarities, rectal cancer and colon cancer are often jointly referred to as colorectal cancer, although their treatments differ.

Most rectal cancers are adenocarcinomas, meaning they develop from the epithelial cells of the rectal mucosa. Colorectal cancer is the third most common cancer in men, following prostate and lung cancer, and the second most common in women, after breast cancer. Although it is the second leading cause of cancer-related death, medical advances in early diagnosis and treatment have significantly improved life expectancy.

Symptoms

The main symptoms of rectal cancer include:

• Hematochezia: presence of bright red or very dark blood in the stool.
• Changes in bowel habits: diarrhea, constipation, or more frequent bowel movements.
• Tenesmus: sensation of incomplete bowel evacuation.
• Narrow stools due to the tumor compressing the intestine and restricting normal stool passage.
• Abdominal pain caused by gas, cramps, bloating, or swelling.
• Unexplained weight loss.
• Extreme fatigue.

Causes

Tumors form due to uncontrolled cell proliferation caused by changes or mutations in their DNA. The reason behind these genetic changes is unknown, but it is believed to result from a combination of environmental and hereditary factors.

Rectal cancer often develops from small growths in the rectal lining, called polyps. However, not all polyps turn into cancer. The type most frequently associated with rectal cancer is the adenomatous polyp or adenoma. The risk of cancer increases when there are more than three polyps, their size exceeds one centimeter, and they show dysplasia, an abnormal cell formation.

Risk Factors

Factors that may increase the likelihood of developing rectal or colorectal cancer include:

• Age: usually occurs after age 50.
• Personal or family history of colorectal cancer or adenomatous polyps.
• Inflammatory bowel diseases, such as ulcerative colitis or Crohn’s disease.
• Hereditary disorders, such as familial adenomatous polyposis or Lynch syndrome.
• Previous radiation therapy treatments in the abdominal or pelvic area.
• Excessive consumption of red, processed, or overcooked meat.
• Type 2 diabetes.
• Sedentary lifestyle.
• Obesity.
• Smoking.
• Alcohol consumption.

Complications

The most common complications of rectal cancer include:

• Anemia due to significant rectal bleeding.
• As the tumor grows, intestinal obstruction that prevents stool passage, potentially requiring emergency surgery.
• Intestinal perforation, which also requires surgical intervention.
• Metastasis, especially when not detected early. Cancer spreads through the intestinal wall to the lymph nodes, liver, or lungs, making recovery more difficult.

Prevention

Rectal cancer can be prevented by addressing its risk factors:

• Reducing consumption of red and processed meat while increasing intake of vegetables, whole grains, and dairy products.
• Avoiding smoking and reducing alcohol consumption.
• Maintaining a healthy weight.
• Exercising regularly.
• Undergoing regular screening tests, such as the fecal occult blood test, to detect precancerous polyps. This is particularly recommended for individuals with a family history of the disease.

Which Doctor Treats Rectal Cancer?

Rectal cancer is diagnosed and treated by specialists in Digestive System and Gastroenterology, General Surgery, and Medical or Radiation Oncology.