March arrives each year as a global reminder that colorectal cancer is not merely a medical issue but a serious public health challenge that societies must confront together. Hospitals, health systems, media outlets, and community partners are now amplifying awareness about colorectal cancer screening, prevention, and early detection. The message is direct and urgent: colon cancer is largely preventable, and timely screening can save lives.
Colorectal cancer develops in the colon or rectum, key organs of the digestive system. The disease begins when cells grow abnormally and divide uncontrollably, forming tumors. The lifetime risk remains significant-about one in 23 men and one in 25 women may develop the disease. In the United States it stands as the third leading cause of cancer-related deaths in both men and women. In Bangladesh, the absence of a comprehensive national cancer registry makes precise statistics unavailable, yet medical professionals confirm it is among the leading causes of cancer-related deaths here as well.
The disease often starts silently but sends warning signals that should never be ignored. Rectal bleeding, blood in stool, persistent changes in bowel habits such as diarrhoea or constipation, narrowing of the stool, abdominal cramping, unexplained anemia, and a constant feeling of incomplete bowel movement are serious symptoms that require medical attention.
Colorectal cancer emerges through a combination of risk factors. Some are modifiable, including obesity, unhealthy diets, low physical activity, smoking, and alcohol consumption. Others cannot be changed, such as aging, genetic predisposition, family history of colorectal cancer or advanced polyps, inflammatory bowel disease, pelvic radiation therapy, race, and Type 2 diabetes. Yet even when risk factors exist, screening offers a powerful opportunity for prevention.
Most colorectal cancers develop from small precancerous polyps that grow slowly over many years before transforming into adenocarcinoma. Detecting and removing these polyps early can stop cancer before it begins. Medical evidence shows survival rates can approach 90 percent when colorectal cancer is detected at an early, localized stage.
Global health authorities now recommend that screening begin at age 45 for adults with average risk. Several screening methods are available. Annual or biennial faecal occult blood tests detect hidden blood in stool. Sigmoidoscopy allows doctors to examine the lower colon every five years. Colonoscopy, the most comprehensive test, enables physicians to examine the entire colon roughly every ten years and remove suspicious polyps during the procedure.
A worrying trend is reshaping the colorectal cancer landscape. Over the past five decades, screening programs significantly reduced colorectal cancer incidence and mortality among older adults. Yet an alarming increase is now occurring among people under the age of 50. Early-onset colorectal cancer has been rising since the mid-1970s, with recent studies indicating annual increases of around three percent.
Young patients frequently develop tumors in the left colon or rectum and often present with symptoms such as rectal bleeding.
Unfortunately these symptoms are frequently mistaken for minor conditions like hemorrhoids, leading to serious diagnostic delays. Research has shown the median time to diagnosis in patients under 50 can be more than seven months compared with about one month for older patients.
Scientists continue to investigate the reasons behind this rise. Genetic syndromes explain some cases, but most remain sporadic. Increasing evidence suggests environmental and lifestyle influences-diets high in red and processed meats, high-fructose sweeteners, heavy alcohol intake, and possible exposure to environmental toxins affecting gut microbiota and chronic inflammation.
Family history also plays a critical role. Individuals with a first-degree relative-parent, sibling, or child-diagnosed with colorectal cancer or advanced adenomas carry significantly higher risk. Advanced adenomas are large polyps or those with high-grade dysplasia or villous features. Such individuals require earlier and more intensive screening strategies to protect future generations.
Lifestyle choices can significantly influence risk. Global studies show frequent consumption of red and processed meats increases colorectal cancer risk by 12 to 21 percent, with risk rising further for each additional 100 grams consumed daily. Alcohol consumption also shows a strong dose-dependent relationship. Even moderate intake can raise risk, while heavy drinking may increase the likelihood of colorectal cancer by more than 50 percent.
In contrast, protective dietary patterns include high intake of fruits, vegetables, fiber, poultry, dairy products, magnesium, and folate. Regular physical activity, maintaining a healthy body weight, quitting smoking, and limiting alcohol consumption all contribute to lowering risk.
Colorectal cancer remains one of the most preventable yet deadly cancers worldwide. Many unnecessary deaths occur every year simply because people are unaware of screening recommendations or avoid medical testing out of fear or hesitation.
Colorectal Cancer Awareness Month in March should therefore serve as more than a symbolic health campaign. It must become a collective social movement reaching beyond hospitals into families, workplaces, religious communities, schools, and social networks. Awareness spreads protection.
Screening is not merely a medical procedure. It is a life-saving decision. If societies speak openly about symptoms, encourage screening at the right age, and adopt healthier lifestyles, thousands of lives can be protected.
Together we can prevent colon cancer. Together we can safeguard future generations. And together we can stop this silent killer before it claims another life.
The writer is a Professor of Surgery, Dhaka Medical College and Hospital. He is also a consultant, Square Hospital
