Most lung cancer patients in India never smoked, genetic makeup big driver: Study

Lung cancer in Southeast Asia is unique and different from other parts of Asia and the West, a recent study has found.

Researchers also found that the genetic makeup of lung cancer in India is "shaped by the intricate diversity of its people", reports India Today.

They further highlighted that most lung cancer patients in India never smoked, and that air pollution can cause lung cancer even in non-smokers.

In light of this, the scientists called for region-centric studies, emphasising that specific climate variables, such as air pollution and other environmental factors, directly contribute to lung cancer.

"Although several guidelines exist, we require a set of dynamic guidelines which change with changing science, and are region-centric, which are developed from data generated in Southeast Asia rather than based on global data," the researchers wrote in the study.

The researchers, including a team from Tata Memorial Hospital, Mumbai, said the India-to-world ratio of lung cancer research produced is 0.51.

Published in The Lancet's eClinical Medicine Journal, the study revealed that lung cancer in India appears around a decade earlier than in Western countries, typically diagnosed between ages 54 and 70.

This is partly due to India's younger population (median age of 28.2 years) compared to the USA (38 years) and China (39 years), it said.

Unique regional risk factors, such as air pollution and genetic mutations, also play a role, the study authors highlighted.

The incidence rate of lung cancer has increased from 6.62 per 1,00,000 in 1990 to 7.7 per 1,00,000 in 2019, with significant rises expected in urban areas by 2025.

The male-to-female ratio of lung cancer cases reflects higher tobacco use among men (42.4% vs. 14.2% among women) as well.

In another paper from the same series, researchers including from the All India Institute of Medical Sciences (AIIMS), New Delhi, analysed the impact of climate change on lung cancer in Asia.

Quoting the World Air Quality Report in 2022, the authors said that South Asia is home to 37 of the 40 polluted cities in the world, and India is among the four most polluted countries.

China, India, Indonesia, Philippines and Thailand, have been the worst hit by national disasters in Asia, and these countries had the highest lung cancer cases in 2020 with over 9.65 lakh new cases, the researchers said.