Most lung cancer patients in India never smoked
What's the story
Scientists have discovered that lung cancer in Southeast Asia, particularly India, differs from other regions due to the unique genetic diversity of its population.
Surprisingly, most Indian lung cancer patients are non-smokers, indicating factors beyond tobacco use.
Air pollution has been identified as a significant cause of lung cancer among non-smokers.
The study was published in The Lancet's eClinical Medicine Journal.
Research insights
Early onset of lung cancer in India: Study findings
The research, conducted by scientists from Tata Memorial Hospital, Mumbai, revealed that lung cancer diagnosis typically occurs between ages 54 and 70 in India.
This is about a decade earlier than in Western countries.
This is attributed in part to India's younger population, with a median age of 28.2 years, compared to 38 years in the USA and 39 years in China.
Statistics
Rising incidence of lung cancer in India: Tobacco consumption
The incidence rate of lung cancer in India increased from 6.62 per 100,000 in 1990 to 7.7 per 100,000 in 2019, with a significant urban rise expected by 2025.
Dr. Tanureet Sandhar, Consultant Physician at CanCure Clinic in Phagwara, attributes this increase to lifestyle changes, particularly tobacco consumption.
Southeast Asian countries are among the highest producers and consumers of tobacco, with India ranking as the world's second largest consumer and third largest producer of tobacco.
Air pollution
Risk ractors and trends in lung cancer among non-smokers
Several studies indicate a significant proportion of lung cancer cases in Southeast Asia are among never-smokers, ranging from 40% to 50% in India and 83% in South Asian women.
Important risk factors include air pollution, particularly PM2.5 in urban areas, and occupational exposures like asbestos in construction industries.
Second-hand smoke from biomass fuel in rural areas also contributes.
Genetic susceptibility, hormonal factors, and pre-existing lung conditions are additional contributors to rising lung cancer rates in non-smokers.
Environmental impact
Climate change and lung cancer in Asia
A related study by the All India Institute of Medical Sciences (AIIMS), New Delhi, examined the impact of climate change on lung cancer in Asia.
The World Air Quality Report 2022 revealed that South Asia is home to 37 of the world's 40 most polluted cities, with India among the four most polluted countries.
The authors noted that as climate change continues to unfold, it exacerbates the burden of lung cancer, already a significant public health challenge in Asia.
Case distribution
High lung cancer cases in Asia's worst-hit countries
Countries including China, India, Indonesia, Philippines, and Thailand have been severely affected by national disasters and recorded the highest lung cancer cases in 2020 with over 965,000 new cases.
These nations are among the worst hit by pollution and climate change in Asia.
The high incidence of lung cancer underscores the urgent need for region-centric studies and dynamic guidelines to address this growing public health challenge.
Dual burden
TB and lung cancer in Southeast Asia and India
The coexistence of tuberculosis (TB) and lung cancer in Southeast Asia adds to the complexity of lung cancer cases in India.
TB and lung cancer may present concurrently or sequentially, with instances where TB precedes lung cancer or vice versa.
This dual burden underscores the need for comprehensive strategies in managing and treating both diseases effectively within the region, highlights Sandhar.