KOLKATA: Non-smokers and the young, who do not use tobacco in any form, are increasingly being diagnosed with lung cancer, leading to concerns among oncologists about environmental pollution and other undetected triggers that could be causing the disease.There is a growing and concerning shift in the lung cancer landscape in Bengal and the rest of India, where an increasing number of patients are non-smokers, including women and young adults, oncologists pointed out on the eve of Lung Cancer Day on Saturday.This challenges the long-held perception that lung cancer is primarily a smoker’s disease. While tobacco remains a major risk factor, it is no longer the only reason, they said.Environmental, occupational and lifestyle exposures were playing a significant role in lung cancer incidence, especially among the urban and semi-urban population, said Charnock Hospital pulmonology head Soumya Sengupta.
Pollution factor
“Smoke from chullahs and passive smoking are major triggers for lung cancer among non-tobacco users. Also, those working in aluminium, metal processing or cement plants or living close to them are susceptible to lung cancer. The fine particles and dust from these plants lead to lung inflammation, which may turn cancerous in the long run. Any sustained exposure to environmental smoke or dust makes one prone to the disease. Also, those with severe COPD or lung diseases are prone to develop lung cancer, even if they are non-tobacco users,” added Sengupta.Shyam Krishnan, pulmonologist, CMRI Hospital, said one of the most critical contributors was prolonged exposure to air pollution.“Fine particulate matters, especially PM2.5, penetrate deep into the lungs and cause chronic inflammation, DNA damage and cellular changes over time. Many Indian cities, including Kolkata, consistently record air quality levels far above safe limits, and this long-term exposure significantly raises lung cancer risk, even among those who have never smoked. Indoor air pollution from cooking fumes, biomass fuel use, incense sticks, mosquito coils and poor ventilation further compounds the problem, particularly for women, who spend more time indoors,” added Krishnan.Sengupta, however, argued pollution did not lead to lung cancer. “Particulate matters may trigger COPD or asthma but can’t cause cancer,” he said.Ruby General Hospital oncologist Sanjoy Roy said around one-third of lung cancer patients he encountered had no tobacco use history.“ Genetic mutations are also responsible. They are possibly being triggered earlier and in a cancerous form due to pollution, stress or other lifestyle reasons. Also, more women are now getting the disease,” added Roy.Occupational exposure was an under-recognised risk.Young working professionals might be exposed to harmful substances, such as asbestos, silica, diesel exhaust, heavy metals and chemical fumes in construction, manufacturing, mining and industrial settings, said oncologists.“Often, the effects of these exposures manifest years later, making the connection difficult to identify. Additionally, passive smoking—regular exposure to second-hand smoke at home or in public spaces, continues to be a significant risk factor,” said Krishnan.But occupational factors were less likely to be the cause in cities, argued Roy.The rise in pollution was the leading non-tobacco reason behind lung cancer, said oncologist Subir Ganguly.“Tobacco is not the only cause but one of the major triggers. The way pollution has increased, anyone is now vulnerable. While gene mutation is another cause, a large number of non-smoking women remain exposed to fuel smoke and passive smoking. They are now being diagnosed more frequently and earlier , say even a decade ago,” added Ganguly.Certain genetic mutations associated with lung cancer were more commonly seen in non-smokers and women, said Krishnan.“These cancers often behave differently and may respond better to targeted therapies if diagnosed early. But because these individuals do not fit the ‘typical’ lung cancer profile, symptoms are frequently overlooked or misattributed to allergies, asthma, infections or stress.”“Young Indians, in particular, tend to delay seeking medical attention. Early symptoms such as a persistent cough, breathlessness, chest discomfort, recurrent respiratory infections, unexplained weight loss or fatigue are often dismissed as lifestyle-related issues. By the time medical advice is sought, the disease may already be at an advanced stage. This delay in diagnosis is one of the biggest challenges we face today,” said Krishnan.
