Previous pulmonary tuberculosis enhances the risk of lung cancer: systematic reviews and meta-analysis

Purpose The possible association between history of pulmonary tuberculosis (TB) and lung cancer (LC) has attracted researchers' attention for several decades. This systematic review and meta-analysis aim to assess the association between previous pulmonary TB infection and LC risk. Methods A Systematic and comprehensive search was performed in the following databases: PubMed, Embase, clinical key, Web of Science and Google Scholar, in articles and abstracts published from 1987 to 2021. Thirty-two articles (involving 50,290 cases and 846,666 controls) met the inconclusive criteria. The Comprehensive Meta-Analysis version 2.2 software was used for this meta-analysis. Results The result of this meta-analysis demonstrates that pre-existing active pulmonary TB increases the risk of LC (RR = 2.170, 95% confidence interval [CI] 1.833-2.569, p < .001, I-2 = 91.234%). The results showed that the risk of the history of active pulmonary TB infection in adenocarcinoma was 2.605 (95% CI 1.706-3.979, p < .001, I-2 = 55.583%), in small-cell carcinoma was 2.118 (95% CI 1.544-2.905, p < .001, I-2 = 0.0%), in squamous-cell carcinoma, was 3.570 (95% CI 2.661 - 4.791, p < .001, I-2 = 42.695%) and 2.746 (95% CI 2.300-3.279, p < .001, I-2 = 41.686%) for other histological types of LCs. According to these results, a history of active pulmonary TB increases the risk of LC. Conclusions This study emphasizes the importance of LC screening in pulmonary TB patients even after the infection is treated. With the increased chances of LC in a patient who had a history of active pulmonary TB, there could be a need for a further follow-up period after pulmonary TB recovery.