Associated factors of co‐existent pulmonary tuberculosis and lung cancer: A case‐control study

BACKGROUND: Although the incidence of co-existent pulmonary tuberculosis (PTB) and lung cancer in China is increasing, risk factors related to its development are still poorly understood. We aimed to investigate which clinical factors were associated with the odds of co-existent PTB and lung cancer (PTB-lung cancer) cases in a case-control study. METHOD: A total of 125 PTB-lung cancer patients were enrolled by Beijing Chest Hospital as the case group between January 2012 and December 2016. Age- and sex-matched PTB-only (N = 125) and lung cancer-only (N = 125) patients were selected as the control groups. Data were collected from the medical records and computed tomography (CT) reports. The case group was further categorized into three sub-groups according to the diagnosis intervals between previous PTB and lung cancer (<1 year, 1-10 years, and > 10 years). RESULT: Compared with both controls of PTB-only and lung cancer-only patients, the PTB-lung cancer case group had significantly higher proportions of patients with irritant cough, expectoration, hemoptysis, fever and CT features of irregular mass and pleural thickening. For PTB patients, fibrous calcification (OR, 2.193; 95%CI, 1.168-4.117) was associated with higher odds of lung cancer (P-value < .05). CONCLUSION: Distinct clinical symptoms and CT tests may help with the early diagnosis of PTB-lung cancer cases. PTB patients with fibrous calcification may have a higher risk of lung cancer. Further multicenter prospective studies are required to validate our findings.