What once primarily affected elderly male smokers has now shifted dramatically, with roughly 50 per cent of lung cancer cases now occurring in non-smokers. The age group has shifted from 50-60s to 30-40s, and approximately 40 percent of diagnoses are now in women, according to Dr Arvind Kumar, Chairman of Lung Transplant and Chest Surgery at Medanta, Gurugram.
Various Indian studies peg between 40 to 52 per cent the prevalence of lung cancer in non-smokers. This is significantly higher than in Western countries. India's deteriorating Air Quality Index is one of the most obvious causes of rising lung cancer mortality rates, with each 10 µg/m³ increase in PM2.5 concentrations associated with a 9 per cent increase in lung cancer risk.
The main culprits:
Outdoor air pollution: Fine particulate matter (PM2.5), ozone, and nitrogen dioxide from vehicular emissions and industrial activity penetrate deep into lung tissue, causing inflammation and cellular damage. The World Health Organisation officially categorises outdoor air pollution as a carcinogen. Delhi alone has witnessed lung cancer cases doubling due to pollution, noted Dr Vinayak Maka, Consultant, Department of Medical Oncology at Ramaiah Institute of Oncosciences, Ramaiah Memorial Hospital, Bengaluru. Scientific evidence shows air pollution is now the second leading cause of lung cancer globally.
Indoor air pollution: Cooking with solid fuels, biomass, kerosene, wood, or coal emits harmful gases. High-heat Indian cooking methods like tadka and deep frying produce ultrafine particles, explained Dr Abhijit Ahuja, Pulmonologist, Saifee Hospital, Mumbai. Poor ventilation traps pollutants indoors, creating chronic exposure. Radon gas, a naturally occurring radioactive substance, can accumulate in basements and poorly ventilated areas.
Secondhand smoke exposure: Despite being non-smokers, many individuals face a significant risk through passive smoking. Dr Manikandan Venkatasubramaniyan, Senior Consultant, Surgical Oncology, MGM Cancer Institute, Chennai, identifies secondhand smoke as a major threat, particularly affecting family members living with smokers.
Occupational and chemical exposure: People working in certain industries, including construction, mining, and shipbuilding, face asbestos exposure. Industrial workers encounter arsenic, beryllium, and diesel exhaust. These substances significantly raise cancer risk, especially when combined with other factors.
Genetic factors and molecular changes: Dr Jeyhan Dhabhar, Consultant Medical Oncology, Jaslok Hospital and Research Centre, Mumbai, highlights that some non-smokers, particularly younger women, develop lung cancer due to specific genetic mutations like EGFR or ALK. Studies in Southeast Asia, including India, show EGFR mutations in 23-30 per cent of patients and ALK rearrangements in 5-7 per cent. Dr Shriniwas Kulkarni, Consultant Medical Oncologist, Sahyadri Super Speciality Hospital, Hadapsar, explains that these mutations can cause cells to proliferate uncontrollably, but the positive news is that these cancers often respond well to targeted therapies.
Pre-existing lung conditions: Chronic lung diseases create additional risk. COPD and pulmonary fibrosis elevate risk due to chronic inflammation. Previous tuberculosis can leave scarred lung tissue that may transform into cancerous growths over time, according to Dr Mandeep Singh Malhotra, Director of Surgical Oncology, CK Birla Hospital, Delhi. Long-term respiratory infections like asthma, pneumonia, and bronchitis increase vulnerability.
Lung cancer is no longer a smoker's disease. One needs to understand the diverse risk factors to stay safe from this health condition. Consult a health expert for more information.
