Rising Air Pollution Increases Risk for Lung Cancer
While the correlation between air pollution and diseases such as asthma, bronchitis and coronary heart disease if often cited by health and environmental experts, doctors are now pointing towards a perceived link between deteriorating air quality in our cities and increase in incidence of lung cancer. There has been a steady rise in incidence of lung cancer in India in the past decade. While smoking and exposure to tobacco remains the leading cause of lung cancer, another emerging risk factor is the dangerous mix of air pollutants breathed in daily, especially among the urban population.
Lung cancer is among the top five cancers prevalent in both men and women across the world.World Health Organization attributes 1.59 million deaths every year globally to lung cancer. In India, an estimated 63,000 new lung cancer cases are reported annually with a slim 5 year survival rate of 10-15 %. Lung cancer causes an estimated 6.8 deaths per 1000 population in India. The Global Burden of Disease Project 2010 attributed an estimated 3.2 million deaths worldwide to air pollution, including 223,000 to lung cancer.
There is little doubt that smoking is the leading instigator of lung cancer. However, in recent years we are coming across a lot of male and female patients who never smoked. Pulmonologists in cities with high air pollution levels frequently talk about the effects of poisonous air on the respiratory system of residents. In recent years, there is growing evidence that the dangerous mix of pollutants in our air also increases risk of lung cancer.
Urban air contains many known carcinogens (cancer causing agents) such as suspended particulate, nitrogen dioxide, sulphur dioxide, carbon monoxide and polycyclic aromatic hydrocarbons, among others. These components are believed to trigger cancerous mutation in the body’s cells.
The International Agency for Research on Cancer (IARC) has already declared outdoor air pollution as a carcinogen. While there is no such comprehensive study in India linking air pollution to increasing lung cancer, clinical evidence suggests that this factor might be increasing people’s risk. Unfortunately, a large number of people in India, especially women and children are exposed to second hand smoke. When combined with smoking and exposure to second hand tobacco, air pollution tends to highly magnify the risk of lung cancer. Due to the interactions between exposures, the combined attributable risk for lung cancer becomes considerably high.
The writer is Dr. KV Veerendra Kumar, Prof, Dept. of Surgical Oncology, Kidwai Memorial Institute of Oncology,Bengaluru.