Utility of LDCT in Lung Cancer Screening in a TB Endemic Region

Lung cancer screening with low-dose computed tomography (LDCT) has been recently shown to result in a significant reduction in lung cancer-specific mortality. However, the utility of LDCT screening in developing countries with high incidence of tuberculosis has not been adequately studied. The investigators hypothesize that LDCT screening in tuberculosis endemic regions is likely to yield a large proportion of false-positive results, especially in the initial round of screening, posing a significant burden on the healthcare system. Herein, the investigators assess the utility of LDCT and its cost-effectiveness in India.

Screening for lung cancer may reduce lung cancer mortality by diagnosing the disease at an early stage when it is treatable more effectively. There are several methods available for screening of lung cancer. These include sputum cytology, chest radiography, computed tomography (CT) of the chest, and positron emission tomography (PET). However, sputum cytology and chest radiography have been found to be ineffective as screening tests for lung cancer as there is no reduction in lung cancer mortality. The use of CT or PET for lung cancer screening may be associated with unacceptable levels of radiation exposure and enormous cost. Low-dose computed tomography (LDCT) of the chest is a special type of CT, which uses relatively low radiation exposure to create a low-resolution image of the entire thorax. The radiation exposure associated with LDCT is 5-6 times less than that of a conventional CT scan of the thorax. LDCT screening has been to shown to result in a 20% reduction in lung cancer-specific mortality. Several national and international guidelines recommend this strategy for lung cancer screening. Despite these guidelines and recommendations by several organizations, lung cancer screening has not been established in several developing countries, where a controversy arises due to high rates of granulomatous diseases like tuberculosis. Emerging evidence indicates that false positive results with LDCT in developing countries may not be unacceptably high as previously believed. In this study, the investigators intend to assess the utility of lung cancer screening using low-dose computed tomography (LDCT) in India, a country with high prevalence of tuberculosis.