15 Year Olds Getting Gastrointestinal Cancer (Credits: iStock) Doctors in Delhi are reporting gastrointestinal (GI) cancer patients as young as 15, raising fresh concerns about whether prolonged exposure to air pollution could be contributing to cancer risk among younger people. The reports have brought renewed attention to the health consequences of Delhi’s polluted air, with experts stressing the need for more research into the possible relationship between environmental pollutants and cancers developing at an unusually young age. The concern was highlighted at an international conference on colorectal and other GI cancers organised by Sir Ganga Ram Hospital and the UK's The Christie NHS Foundation Trust on October 10 and 11. Dr Shyam Aggarwal, chairperson of medical oncology at Sir Ganga Ram Hospital, said his department was seeing new GI cancer patients as young as 15, which he described as uncommon five years ago. While the cases have raised questions about environmental exposure, doctors caution that they do not establish air pollution as the cause. Nevertheless, the concern is significant in a city where prolonged exposure to polluted air remains a major public health challenge. Air pollution is widely recognised as a health hazard, with its effects extending beyond the respiratory system. Fine particulate matter, particularly PM2.5, is a major concern because these microscopic particles can penetrate deep into the lungs and trigger biological responses that damage cells. Explaining the risks, Dr. Shivakumar K, MD, Respiratory Medicine and Chief Consultant Pulmonologist at Kauvery Hospital, Marathahalli, Bengaluru, said, “Fine particulate matter, especially PM2.5, can penetrate deep into the lungs and trigger oxidative stress and inflammation. With prolonged exposure, these particles can impair normal lung development, reduce lung function and increase the risk of respiratory conditions such as asthma.” The concern is not limited to immediate respiratory symptoms. According to Dr. Shivakumar, the effects of repeated exposure during childhood may extend well into adulthood. “Pollutants can damage cells, promote chronic inflammation and contribute to the accumulation of cellular injury over time. Certain components of air pollution, including diesel exhaust and particulate matter containing carcinogenic compounds, are also associated with an increased risk of lung cancer,” he said. Can air pollution cause Gastrointestinal Cancer (Credits: iStock) Outdoor air pollution is classified as carcinogenic to humans by the International Agency for Research on Cancer, particularly because of the established evidence linking it to lung cancer. However, the evidence connecting air pollution to gastrointestinal cancers is still developing. A systematic review and meta-analysis published in Epidemiologic Reviews in January 2026 examined 70 studies investigating air pollution and gastrointestinal diseases. It found that long-term PM2.5 exposure was associated with higher mortality from gastrointestinal cancers, with the strongest association observed for colorectal cancer. Such findings indicate a possible relationship but do not prove that pollution directly causes GI cancer in an individual. The emergence of GI cancer in very young patients raises an important question: could environmental exposure be one of several factors contributing to cancer risk? While research into pollution and cancer continues, doctors caution against drawing conclusions about individual cases without a detailed clinical assessment. Dr. Shivakumar emphasised the need to distinguish an established environmental risk from the cause of a particular diagnosis. “Lung cancer at 15 is exceptionally rare, and while air pollution is a recognised carcinogenic exposure, we cannot conclude that pollution alone caused cancer in a particular teenager without a detailed clinical evaluation. Cancer generally develops through multiple biological processes, and individual cases require careful investigation,” he said. It is also important to distinguish between lung cancer and GI cancer. Although outdoor air pollution is an established carcinogenic exposure, the reported cases of GI cancer in Delhi's younger patients do not demonstrate that polluted air is responsible. GI cancers include malignancies affecting the stomach, colon, rectum, oesophagus, pancreas and other parts of the digestive system. Their risk factors vary and can include inherited genetic conditions, family history, certain infections, dietary patterns and other lifestyle or environmental exposures. Doctors' observations are an important reason to investigate further, but establishing whether cancer rates are rising among younger people requires reliable population-level data, comparisons over time and research examining multiple risk factors. While researchers continue to investigate the long-term consequences of pollution, reducing exposure is an important preventive measure, particularly