Epidemiology of lung cancer in India: Focus on the differences between non-smokers and smokers: A single-centre experience

Context: Lung cancer has varied epidemiology depending on the geographic region. Globally, there have been important changes in incidence trends amongst men and women, histology, and incidence in non-smokers. Indian epidemiological data on lung cancer is scarce. Aims: We set out to study the epidemiological patterns and clinical profile of lung cancer in India. Materials and Methods: We interviewed patients discussed in the thoracic oncology multidisciplinary meetings between 2008 and 2009. Demographic data, smoking history, place of residence, histology, stage at presentation, and treatment details were collected. Data was entered and analyzed in SPSS. Results: There were 489 patients, with a median age of 56 years, of which 255 (52) were non-smokers and 234 (48) were smokers. One hundred and thirty-three patients had consumed smokeless tobacco. The male-to-female ratio was 3.5:1. Sixty-nine patients (14.1) were incorrectly diagnosed and treated with anti-tuberculosis treatment, which delayed the diagnosis of lung cancer by four months. Eight percent of patients had small-cell carcinoma; of the 92 patients with non-small-cell carcinoma (NSCLC), the most common histology was adenocarcinoma (43.8), followed by squamous cell (26.2), large cell (2.1) and other (8.3). Eighteen percent of patients were diagnosed by cytology, therefore were diagnosed as NSCLC, without further histologic subtyping. Most patients (43) were in Stage III at presentation. Lung followed by bone were the common sites of metastases. The majority of the patients (49) received palliative chemotherapy. Among definitive therapy, concurrent chemo-radiation (13) was offered more frequently than surgery (6). Conclusion: Considerably higher numbers of Indian patients with lung cancer are non-smokers, compared to the West. The global trend of rise in adenocarcinoma is paralleled in India. Non-tobacco-related risk factors need further investigation.