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India is grappling with a severe cancer epidemic, emerging as Asia's second-largest battleground against the disease. According to World Cancer Research Fund International, lung cancer is the most common cancer in men and the 2nd most common cancer in women globally
Grim statistics from the research suggests a chilling 75,000 lives were claimed by lung cancer in India alone in 2022, a figure disproportionately skewed towards men with 54,000 deaths. The crisis is far from abating, with projections indicating a sharp surge in cases to 81,219 among men and 30,109 among women by 2025, research suggests.
A research published in the Journal of Thoracic Oncology states that in India, lung cancer accounts for 5.9 per cent of all cancers and 8.1 per cent of all cancer-related deaths
Exacerbating this health emergency is India's severe air pollution crisis. Ranked fifth globally in terms of air pollution, the country is home to a staggering 21 of the world’s 30 most polluted cities, as per a 2023 study published in Nature’s Scientific Reports. PM2.5 levels in India are a shocking eleven times the World Health Organization’s safe limit. This toxic air, particularly concentrated in cities like Delhi and Ahmedabad, is accelerating the lung cancer epidemic, with a startling one in six men and one in seven women at risk.
Industry experts concur that while tobacco use remains a significant contributor to lung cancer, the alarming rise in cases among non-smokers underscores the critical role of air pollution in driving this deadly disease. This lethal combination of smoke and smog has created a perfect storm, demanding urgent and comprehensive action to protect public health
A Toxic Brew: Environmental Factors and Lung Cancer
Sachin Almel, Section Head - Medical Oncology, P. D. Hinduja Hospital and Medical Research Centre, Mumbai, confirms that PM2.5 is a primary culprit in environmental lung cancer. The Lancet Commission on Pollution and Health has established that all forms of pollution contribute to 43 per cent of lung cancer deaths, with air pollution alone accounting for up to 29 per cent globally, he adds.
Beyond PM2.5, Almel highlights a range of environmental factors contributing to lung cancer risk in India. These include exposure to second-hand smoke, indoor air pollution from burning biomass fuels, environmental radiation from radon gas, and radiation from medical procedures. Industrial activities involving exposure to asbestos, arsenic, nickel, thorium, and other heavy metals pose significant risks. Agricultural practices involving pesticides and fertilisers also contribute, as does exposure to pollutants from welding and improper waste disposal.
Vulnerable Populations
The impact of air pollution on lung health is particularly severe for certain demographics. Mayank, Additional Director - Pulmonology, Fortis Hospital, Noida emphasises that the subset of the population living in areas with AQI exceeding 300 is particularly vulnerable to lung-related diseases. Individuals residing near industries or chemical-emitting industrial sectors are at higher risk.
Sourabh Pahuja, Senior Consultant, Department of Pulmonary Medicine, Amrita Hospital Faridabad, adds that pollution-induced lung cancer cases are rising, with higher rates among populations with significant exposure to air pollution, such as factory workers, coal miners, and those in silica and asbestos industries. Women living in villages using solid fuel for cooking are also at increased risk, he states.
Genetics and the Environment: A Complex Relationship
Dipanjan Panda, Senior Consultant, Medical Oncology, Indraprastha Apollo Hospitals at Apollo Cancer Centre underscores the complex interplay between genetics and environment in lung cancer development. “Genetic variations can influence an individual's susceptibility to carcinogens, DNA repair, and immune response to pollutants. Genetic factors related to inflammation and oxidative stress may amplify the carcinogenic effects of air pollution. Furthermore, epigenetic modifications, influenced by environmental factors, can alter gene expression and contribute to lung cancer risk,” he opines.
A Growing Threat: The Impact on Children
The consequences of air pollution extend beyond adult health. Research suggests that exposure to air pollution during childhood, when the lungs are still developing, can have long-term implications for respiratory health. Panda emphasises that air pollution can stunt lung growth, reduce lung capacity, and cause inflammation, increasing the risk of asthma, bronchitis, COPD, and lung cancer later in life. Prenatal exposure can also impact fetal lung development, he remarked.
Mayank highlights the alarming increase in respiratory problems among children in recent years, attributing it to worsening air quality. “The use of respiratory devices like nebulisers has surged, indicating a growing burden of respiratory diseases among young populations,” he adds.
The Role of Air Purifiers: A Limited Solution
While air purifiers are often touted as a solution, experts have mixed views on their effectiveness in preventing lung cancer.
Almel suggests that while air purifiers may be beneficial in specific indoor settings with high smoke levels, their impact on lung cancer risk is uncertain, especially in the Indian context.
Air purifiers can help reduce exposure to PM2.5 and certain chemical fumes, but their effectiveness in preventing cancer is yet to be proven, states Dr Mayank.
Precision Medicine and Liquid Biopsy
Suruchi Aggarwal, PhD - Head - Scientific Affairs, discussing about the advancements in treatment stated , “T he advancement of lung cancer treatment has been significantly improved by precision medicine, with genetic testing taking a lead role. Next-Generation Sequencing now enables the concurrent analysis of multiple biomarkers, including EGFR, ALK, and ROS1, thereby facilitating tailored therapies. While tumor biopsy remains the gold standard, liquid biopsy has emerged as a valuable adjunct, offering insights through the analysis of circulating tumor DNA. This non-invasive method provides a critical alternative when biopsies are not feasible, complements conventional tumor biopsy, and enables meticulous monitoring of disease progression, relapse, and treatment response. Liquid biopsy is paving the way for more refined and personalised lung cancer care.”
A Call for Urgent Action
The confluence of air pollution and tobacco smoke has created a perfect storm for lung cancer in India. Addressing this crisis requires a multi-faceted approach, including stringent air pollution control measures, tobacco control initiatives, early detection programs, and public awareness campaigns. Protecting the health of future generations necessitates urgent action to reduce air pollution, especially during critical periods of lung development. As Industry experts emphasise, safeguarding the respiratory health of children is essential for preventing the long-term consequences of this silent epidemic.
