Colon cancer rates continue to climb as dietary habits shift toward Westernized patterns. In 2023 alone, 32,610 new cases were reported in South Korea, with the rise in rectal cancer causing particular concern among medical experts. The rectum is the straight section of the large intestine that connects the colon to the anus. Because of its location, late detection of rectal cancer carries a high risk: the potential surgical removal of the anus.
Understanding the Rectum and Patient Demographics
The rectum serves as a temporary storage site for stool before it is expelled. When it becomes full, it triggers the urge to have a bowel movement. According to national cancer registry statistics released last January, there were 15,507 new cases of rectal cancer—nearly half of the total 32,610 colon cancer cases. Patients in their 50s and 60s accounted for approximately half of these diagnoses, highlighting a critical window for screening in middle age.
What Drives the Development of Colon and Rectal Cancer?
While age (50 or older), genetic factors, inflammatory bowel disease, and prior pelvic radiation play roles, lifestyle choices have a profound impact on the development of these cancers. Diets high in animal and saturated fats—specifically red meat and processed meats like ham and sausages—allow carcinogenic substances to accumulate in the intestinal lining. Conversely, a lack of dietary fiber from vegetables and fruits prevents the natural "cleansing" of the digestive tract. Correcting these nutritional habits is considered the first line of defense in prevention.
The Danger of a Sedentary Lifestyle
Studies from the United States and Europe, where colon cancer incidence is traditionally high, show that physically active individuals have a significantly lower risk. Physical activity and exercise stimulate intestinal peristalsis—the wave-like muscle contractions that move food through the digestive system. This process shortens "transit time," reducing the duration that carcinogens in the stool remain in contact with the intestinal mucosa. A habit of sitting for long periods combined with high meat consumption creates a "perfect storm" for rectal cancer development.
Recognizing the Symptoms of Advanced Disease
In its early stages, rectal cancer is often asymptomatic. By the time symptoms appear, the disease is frequently advanced. The most common warning sign is blood mixed in the stool. Other symptoms include changes in bowel habits, such as persistent constipation or diarrhea, and tenesmus—a distressing sensation that the bowels haven't completely emptied after a movement. While mild discomfort may occur, significant pain usually does not manifest until the later stages.
The Priority of Anal Preservation
According to the National Cancer Information Center, preserving anal function is a primary goal of treatment. If a tumor is located within 3–5 cm of the anus and function can be saved, doctors typically utilize radiation and chemotherapy first to shrink the tumor before surgery. However, if the cancer has invaded the anal sphincter, an abdominoperineal resection is often necessary. This procedure involves removing the rectum and the anus, requiring a permanent colostomy (stoma)—an artificial opening in the abdomen for stool passage. Because of this life-altering outcome, early detection and prevention are more critical in rectal cancer than in almost any other gastrointestinal malignancy.
