Doctor explains: Why colorectal cancer is striking younger Indians and how to prevent it

Colorectal cancer (CRC) in India, once deemed a disease of the older population, is increasingly being diagnosed in young adults,  a trend highlighted by recent research and reports from the Indian Council of Medical Research (ICMR) and other national cancer registries. While India still records a lower incidence compared with Western nations, several regional studies indicate sharp increases in younger age groups, often presenting at advanced stages and with aggressive tumour biology.

The rising tide has triggered calls among oncologists for lower screening ages, broader public awareness and a shift in diagnostic strategies. Firstpost talked to Dr. Dinesh Singh, Director of Radiation Oncology at Action Cancer Hospital (Delhi) to discuss  the key drivers behind the shift, practical screening recommendations and the way forward for young Indians.

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What factors are driving the rise of colorectal cancer among young adults, particularly in India?

Dr Singh: The ongoing surge of colorectal cancer in younger adults is multifactorial in India. Changing dietary habits — especially increased consumption of processed foods and red meat combined with low-fibre intake — are major contributors. At the same time, sedentary lifestyles, obesity and escalating use of tobacco and alcohol further heighten risk. Environmental pollution, alterations in the gut microbiome and genetic predisposition also play very significant roles. Equally important is delayed diagnosis: a low level of awareness among younger people and health-care providers often leads to late-stage detection. Notably, urban populations exposed to Westernised lifestyles and heightened stress may see steeper rises.

Should the screening age for colorectal cancer be lowered, given the growing incidence in people under 50?

Dr Singh: Absolutely. Historically, screening for colorectal cancer began at age 50, but with the rising incidence in younger adults, a revision is warranted. Ideally, we should start screening at age 40 and even 35 for high-risk individuals. Those with a family history of colon cancer, inflammatory bowel disease or genetic syndromes such as Lynch syndrome require early surveillance. Early detection through colonoscopy or non-invasive tests allows removal of pre-cancerous polyps and prevention of progression. In India, national guidelines, targeted awareness campaigns and broader screening access must now be prioritised.

How significant are lifestyle factors such as diet, alcohol and physical inactivity in triggering early-onset colorectal cancer?

Dr Singh: Lifestyle factors are among the strongest contributors to early-onset colorectal cancer. According to the World Health Organization (WHO), there is no safe minimum for alcohol consumption: risk increases with volume. Diets rich in red and processed meats but poor in fibre promote gut inflammation and DNA damage, while heavy alcohol use increases oxidative stress. Sedentary behaviour, obesity and chronic stress disrupt metabolic balance and hormone levels, further enabling tumour growth. Meanwhile, modern lifestyles characterised by high screen time, fast-food consumption and limited physical activity also affect gut microbiota which may play a key role. Prevention must emphasise balanced diets, daily activity and moderation.

What are the main barriers to timely screening and diagnosis in India and how can awareness be improved?

Dr Singh: A key barrier is misattribution: many young people dismiss symptoms as haemorrhoids (piles) or minor bowel issues and delay intervention. The biggest obstacles are lack of awareness, stigma and unequal access to diagnostic infrastructure. Many gastrointestinal symptoms are overlooked by both patients and providers under the assumption they are benign. High out-of-pocket costs and limited colonoscopy access outside metropolitan centres further delay diagnosis. To improve awareness, public-health campaigns must emphasise early warning signs and regular check-ups. Corporate wellness programmes, digital health platforms and influencer-led social media dialogue can help normalise discussions around bowel health. Government-backed screening drives and better insurance coverage for colon health assessments are also critical to closing the gap.

Do younger patients show different symptoms or tumour behaviour compared to older individuals?

Dr Singh: Yes. Younger patients often present with more aggressive tumour biology and advanced-stage disease. Symptoms such as rectal bleeding, altered bowel habits or unexplained fatigue are frequently dismissed as stress-related, causing delays in intervention. Studies show that early-onset colorectal cancers tend to be left-sided and microsatellite-instability (MSI) high, indicating molecular differences from later-onset disease. Younger patients also have higher rates of recurrence and faster progression. Thus, any persistent bowel-related symptom in a young adult deserves prompt and thorough evaluation rather than mere symptomatic treatment.

How promising are new screening tools like stool-based tests, liquid biopsies or AI-assisted risk prediction in early detection?

Dr Singh: Emerging technologies are promising for early colorectal-cancer detection. Stool-based tests such as the faecal immunochemical test (FIT) or DNA-based assays (for example, Cologuard) offer cost-effective, non-invasive options. Liquid biopsies detecting circulating tumour DNA (ctDNA) represent another frontier. AI-driven algorithms that analyse genetic, lifestyle and imaging data are potentially game-changing, particularly in resource-limited settings like India where colonoscopy access is patchy. However, for widespread adoption, large-scale validation and cost-reduction remain essential.

What key warning signs should young adults never ignore and when should they seek medical evaluation?

Dr Singh: Young adults should not ignore the following: persistent rectal bleeding, unexplained anaemia, abdominal pain, chronic constipation or diarrhoea, and sudden weight loss. Immediate medical evaluation is warranted for blood in stool, bowel-habit changes lasting more than two weeks, or persistent tiredness. Even mild but recurring symptoms should not be self-treated or attributed to diet alone. A full evaluation including stool tests and colonoscopy  is critical if there is family history of colorectal or GI cancers. Early detection greatly improves chances of survival.