Pulmonary tuberculosis associated with increased lung cancer risk in patients with COPD

Among patients with COPD in South Korea, with an intermediate tuberculosis burden, history of pulmonary TB was associated with an increased risk for developing lung cancer, researchers reported.

“Given that chronic inflammatory process is a potential mechanism of lung cancer development in COPD patients, the history of pulmonary TB might add to the risk of lung cancer development in these patients,” Hye Yun Park, MD, associate professor in the division of pulmonary and critical care medicine in the department of medicine at Samsung Medical Center at Sungkyunkwan University School of Medicine, Seoul, South Korea, and colleagues wrote in the Annals of the American Thoracic Society. “A history of pulmonary TB has been identified as a significant comorbid condition of COPD in countries with an intermediate to high burden of TB.”

The cohort study included 13,165 individuals with COPD (mean age, 66.3 years; 48% women) aged 50 to 84 years in South Korea. Participants were matched to a cohort without COPD (n = 34,467; mean age, 65.3 years; 49.5% women) for age, sex, smoking history and pulmonary TB status to evaluate whether the relationship between pulmonary TB and risk for lung cancer was different. All participants in both cohorts were followed from 2003 to 2015.

Pulmonary TB was diagnosed based on chest radiography results. Incident lung cancer was identified through hospitalization and outpatient visit claims.

History of pulmonary TB was 17.8% in the cohort of participants with COPD compared with 15.9% of participants without COPD.

During a median follow-up of 7.7 years, there were 430 incident lung cancer cases among participants with COPD without a history of pulmonary TB (incidence rate, 524 cases per 100,000 person-years). There were 148 cases of incident lung cancer among participants with COPD and a history of pulmonary TB (incidence rate, 931 cases per 100,000 person-years).

Among participants with a history of pulmonary TB, the HR for lung cancer was 1.24 (95% CI, 1.03-1.5) compared with participants without a history of pulmonary TB. This association between pulmonary TB history and the development of lung cancer was stronger among participants with COPD who were never smokers. The HR for lung cancer was 0.98 (95% CI, 0.78-1.22) among participants without COPD.

Researchers observed no interaction between pulmonary TB, smoking status and COPD.

“Our study suggests that COPD patients with a history of pulmonary TB, who are never smokers, might benefit from periodical screening or assessment for lung cancer development,” the researchers wrote. “Further studies with larger sample sizes at other settings are needed to confirm our findings and elucidate the mechanistic link underlying the complex interplay between pulmonary TB, COPD and lung cancer.”