Air Pollution Leading Cause of Lung Cancer in Non-smokers

Traffic exhaust, smoke due to coal and wood burning, and passive smoking are major risk factors after tobacco

BENGALURU / September 24, 2024: Intake of tobacco (both smoke and smokeless forms) accounts for 21% of total cancer deaths worldwide, including those from lung cancer. Non-smokers can still be at risk for lung cancer due to several factors, even though smoking is the leading cause. Air pollution in various forms poses a significant risk to them. This was said by Dr. Radheshyam Naik, Consultant Medical Oncologist, Hematologist, and Bone Marrow Transplant Physician at Sammprada Hospital, Bengaluru, ahead of the World Lung Day.

He said: “While the risk of lung cancer is lower for non-smokers than for smokers, they should still be aware of non-tobacco risk factors and take steps to minimize their exposure. This is especially important considering the rising incidence of lung cancer among people who have never smoked. Long-term exposure to polluted air increases the risk of lung cancer. A critical component of air pollution includes the airborne particulate matter of different sizes which are a result of combustion from various sources. Motor vehicles emissions contain many human carcinogens like diesel exhaust, benzene, polyaromatic hydrocarbons, and dioxin.”

The doctor said long-term occupational exposure can happen from diesel and gasoline exhaust, inhalable dusts like metals and silica, and working in areas like mining, foundries, truck transportation, carbon black production, and asphalt. This increases the risk of lung cancer for non-smokers.

Dr. Radheshyam Naik added: “The residual risk of developing lung cancer is also significant among former smokers. Ongoing research reports a favorable response to chemoprevention among former smokers when compared with current smokers. Alcohol consumption contributes to 4% of all cancers worldwide, which includes lung cancer.”

Household air pollution is a result of burning of solid fuels, passive smoking, and inadequate ventilation systems. “In the Indian context, since many women tend to work from within their homes and cook very frequently, the exposure at home has a strong impact on their lung health compared with males. When contrasted with clean energy, the coal furnace which is used as a means of domestic heating in rural areas is associated with twice the risk of lung cancer,” he said.

The doctor said that it is important for physicians in India to be trained to recognize the symptoms of lung cancer early. “According to research studies from South India, less than 50% of doctors suspect lung cancer when a patient presents to them with symptoms.

Evidence shows that among Indian lung cancer patients, there exists a delay of about 100 days between developing symptoms and the diagnosis of lung cancer. This duration extends by another 26 days for receiving proper treatment. A higher index of clinical suspicion should be exercised by physicians in India among those at risk for lung cancer,” Dr. Radheshyam Naik.

Low dose spiral CT scanning provides a tool for early detection of lung cancer, as a complete image of the thorax can be obtained during a single hold of breath. It is important to develop lung cancer clinics in hospitals which will enable the appropriate diagnosis and treatment of lung cancer, he added.