Over the past decade, air pollution has become a significant concern in India, particularly regarding the worsening air quality in various regions during the winter months. Research has long established a connection between the air we breathe and respiratory or cardiac illnesses, but experts now highlight a troubling link to a growing health crisis: cancer. The Indian Council of Medical Research (ICMR) anticipates a sharp increase in cancer cases, projecting a rise from 1.46 million in 2022 to 1.57 million by 2025. This means that roughly one in nine individuals in India could receive a cancer diagnosis in their lifetime. Cancer presently ranks as the second leading cause of death from non-communicable diseases in the country. Notably, lung cancer is the second most prevalent cancer among men and among the top five for women, and it remains a leading cause of cancer-related fatalities globally.
Doctors have observed a worrying trend over the last 20 years: an increase in lung cancer cases among non-smokers. Lung cancer was traditionally associated with smoking, which continues to be the foremost risk factor. However, according to Kumar Prabhash, head of solid unit medical oncology at Tata Memorial Hospital in Mumbai, the incidence of this cancer has historically been lower in India compared to Western nations. He notes that, while smoking rates have been higher in the West, the relationship between smoking and lung cancer is changing. Increased cases of lung cancer are now being documented in individuals who have never smoked, with estimates suggesting this demographic may account for up to 30% of current lung cancer cases.
At the Cancer Institute in Adyar, Chennai, research has documented this shift. A study from 2012 indicated that nearly 40% of lung cancer patients were non-smokers, while a 2017 study showed this figure had risen to over 55%. This altered pattern is reflected in the types of lung cancer detected; smokers typically develop squamous cell carcinoma, whereas non-smokers more frequently present with adenocarcinoma, aligning with global trends.
Age demographics also highlight concerns: patients in India are generally a decade younger than their Western counterparts when diagnosed with lung cancer. Alarmingly, non-smoking lung cancer cases are even more prevalent among women than men. This shift necessitates urgent investigations into causes of lung cancer beyond tobacco exposure.
Air pollution has emerged as a potential contributor. Krithiga Shridhar, head of the Cancer Epidemiology Unit at the Centre for Chronic Disease Control in New Delhi, states that outdoor air pollution and particulate matter are classified as Group 1 carcinogens, with substantial evidence indicating their cancer-causing potential; indoor air pollution is deemed a Group 2 carcinogen, where evidence is considered probable. The 2024 World Air Quality Report by IQAir shows India ranking as the fifth most polluted country globally, with an average PM 2.5 concentration of 50.6 micrograms per cubic meter, far exceeding the World Health Organization’s recommended limit of 5.
While there are strong associations drawn between air pollution and lung cancer, more research is essential to establish a direct causative relationship. A 2022 paper in the Indian Journal of Medical Research noted the evolving epidemiology of lung cancer in India and acknowledged air pollution’s role. The study remarked on a decline in tobacco use but an increase in awareness about air pollution’s implications for lung cancer risk.
Indoor air pollution also might play a role, notably among women, due to the burning of solid fuels and biomass for cooking. Although many households have transitioned to cleaner gas sources, historical exposure remains a factor, given lung cancer’s long latency period.
In the northeastern region of India, where cancer rates are notably high and tobacco use is common, experts observe a shift in lung cancer etiology, indicative of broader national trends. Ravi Kannan, director of Cachar Cancer Hospital and Research Centre in Assam, emphasizes that while tobacco remains a significant cause of lung cancer, the influence of air pollution is now more apparent.
However, air pollution isn’t the sole factor. A recent publication in The Lancet Regional Health highlighted the potential role of occupational exposures to harmful substances and genetic predispositions.
Late diagnosis remains a critical issue in India, with lung cancer often diagnosed at advanced stages due to nonspecific symptoms such as cough and chest pain. Partha Pratim Medhi, assistant professor of radiation oncology at AIIMS Guwahati, notes that healthcare practitioners often prioritize tuberculosis over lung cancer, leading to delays in diagnosis. Studies indicate that nearly half of lung cancer patients present with Stage IV disease, severely impacting survival rates.
Improvement in diagnostic facilities has occurred, with advances in molecular testing aiding treatment planning. However, accessibility remains limited outside tier 1 and tier 2 cities. Treatment options are available but often unaffordable; immunotherapy, which has shown promise elsewhere, remains only partially accessible in India, with many approved drugs being prohibitively expensive.
Experts call for a better understanding of air pollution’s health impacts, urging for extensive research on lung cancer causes beyond smoking. As India grapples with approximately 75,000 new lung cancer cases annually, a projection indicates this could rise to 100,000, underscoring the need for immediate action. The way forward requires a multi-faceted approach to combat pollution and a commitment to research aimed at elucidating its relationship with cancer.
Original Source: https://www.thehindu.com/sci-tech/health/cancer-is-on-the-rise-in-india-could-air-pollution-be-a-factor/article69648732.ece
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Publish Date: 2025-06-03 07:00:00
