Mumbai's Lung Cancer Burden Rising Among Non-Smokers: Report
As India observes World Cancer Day, alarming data from cancer registries reveals a significant shift in the country's lung cancer landscape, with Mumbai emerging as a critical hotspot for cases among individuals who have never smoked. A recent report titled Cancer Incidence in India, published by the Centre for Cancer Epidemiology at Tata Memorial Centre, highlights this concerning trend, indicating that adenocarcinoma has surpassed squamous cell carcinoma as the dominant lung cancer subtype in the city, particularly affecting women.
Adenocarcinoma Takes the Lead in Mumbai
The report shows that adenocarcinoma now accounts for 56 per cent of lung cancer cases in Mumbai, compared to 28 per cent for squamous cell carcinoma and 16 per cent for small cell carcinoma. This subtype is notably more common among non-smokers, pointing to environmental and genetic factors as primary contributors. Dr. Atul Budukh, Professor of Epidemiology at Tata Memorial Centre and lead author of the report, emphasized that these findings challenge traditional assumptions about lung cancer.
"Mumbai's cancer data tells us that lung cancer is no longer just a smoker's disease. Air pollution, occupational exposures, and genetic factors are driving cases among never smokers. This demands a shift in both public health messaging and clinical management," Dr. Budukh stated.
National and Regional Cancer Statistics
According to the National Cancer Registry Programme, India recorded an estimated 1.56 million new cancer cases and 8,74,404 deaths in 2024, with lung cancer ranking among the leading causes of cancer-related mortality. Among men, cancers of the trachea, bronchus, and lungs accounted for 74,763 cases (9.6 per cent of all cancers) and 56,818 deaths (12.3 per cent). Among women, lung cancer contributed 30,446 cases (3.9 per cent) and 24,055 deaths (5.8 per cent).
A 2024 review published in The Lancet Regional Health Southeast Asia found that lung cancer in India presents nearly a decade earlier than in Western countries, with a mean age ranging from 54 to 70 years. The review also noted that 40 to 50 per cent of Indian lung cancer patients are non-smokers, a proportion that rises to 83 per cent among South Asian women. Survival outcomes remain starkly unequal, with India's five-year survival rate at 3.7 per cent, compared to 21.2 per cent in the United States and 32.9 per cent in Japan.
Mumbai's Distinct Risk Factors
Regional contrasts further underline Mumbai's unique risk profile. While in the North East, especially Mizoram, lung cancer remains the leading cause of cancer mortality driven by high tobacco consumption, Mumbai's burden is increasingly shaped by urban air pollution and occupational exposures rather than tobacco alone. Long-term trend data spanning 25 years shows a steady rise in adenocarcinoma, with higher prevalence among women.
Projections from GLOBOCAN estimate that India's overall cancer burden will exceed 2.2 million cases by 2040, with lung cancer continuing to rise. In Mumbai, case numbers are expected to climb sharply by 2025, with an estimated 81,219 men and 30,109 women likely to be diagnosed.
Complicating Factors and Expert Recommendations
Tuberculosis further complicates diagnosis and treatment, with research indicating that up to 29 per cent of lung cancer patients were initially misdiagnosed as TB, leading to delays in care. Drug interactions between TB treatment and cancer therapies also pose significant clinical challenges.
Experts at Tata Memorial Centre have called for:
- Expanded molecular testing
- Affordable access to targeted therapies
- Stricter tobacco control
- Integrated tuberculosis and cancer screening programmes
Dr. Budukh warned, "We need collaborative research, political will, and patient advocacy. Without these, the gap between what is possible and what is accessible will only widen."
