AIIMS, Harvard gastroenterologist shares 8 signs of colon cancer: Blood in stool, unexplained weight loss and more | Health

Colon cancer contributes to one of the most common cancer-related deaths globally. It is the second leading cause. In a WHO report from July 2023, 1.9 million new cases of colorectal cancer were recorded in 2020. This indicates the seriousness of the diseases, highlighting the need for early detection that may improve survival rates. In an Instagram post shared on August 31, Dr Saurabh Sethi, a gastroenterologist and liver specialist trained at AIIMS, Harvard and Stanford Universities, shared the signs, some of which many people may even confuse with comparatively less-threatening conditions like haemorrhoids.

Signs of colon cancer

Knowing the signs is important as colon cancer can develop quietly. But by being aware of the early signs, one can seek out timely treatment, increasing survival chances. Dr Sethi listed these warning signs:

1. Blood in stool: Bright red or dark, tarry stools can signal bleeding in the colon. Don’t assume it’s just haemorrhoids.
2. Persistent bowel changes: Constipation, diarrhoea, or narrowing of stools lasting more than a few days. It is a red flag.
3. Abdominal pain or cramping: Frequent bloating, cramps or abdominal pain that’s new or unexplained deserves a check-up.
4. Unexplained weight loss: Losing weight without dieting or lifestyle changes could mean your gut is not absorbing nutrients properly.
5. Ongoing fatigue: Chronic tiredness, weakness or dizziness may result from slow blood loss and anaemia.
6. Unexplained iron-deficiency anaemia: If labs show low iron, especially in men or post-menopausal women, it can be an early hidden sign.
7. Feeling of incomplete emptying: If it feels like you ‘can’t finish’ after a bowel movement, it may point to blockage or tumour growth.
8. Family history: Having close relatives with colon cancer increases your risk; don’t delay screening if symptoms appear.

Dr Sethi mentioned that most colon cancers start silently, but when detected early, the five-year survival rate is as high as 90 per cent. This is why he urged not to ignore the warning signs and delay screening. Colonoscopy can save lives.

What to eat to reduce risks?

Much of the prevention lies in lifestyle habits, too, including dietary options. In a WebMD report from June 2025, for colorectal cancer, which is a broader term that includes both cancers of the colon and rectum, adoption of whole grains like oatmeal, whole wheat bread, and brown rice was suggested, as they help with bowel movement. Similarly, include beans, peas, and lentils in the diet, as they are legumes rich in fibre and protein, and contain flavonoids. Colourful veggies like broccoli, cabbage, and oranges (rich in vitamin C) contain phytochemicals which stop the growth of cancer cells. Omega-3 fatty acids are another nutrient that is good in the diet, found in sources like salmon.

Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.