Setting: The deterioration of immunity in cancer patients may be associated with a higher incidence of tuberculosis (TB).
Objective: Despite several previous studies on cancer and TB, no population-based investigation has been published. We performed a nationwide population-based study to investigate the incidence of active TB among cancer patients, and the cancer-type specific risk factors related to TB.
Designs: This nationwide population-based retrospective cohort study was based on data obtained from the Taiwan National Health Insurance Database. A total of 16,487 cancer patients and 65,948 controls matched for age and sex were recruited.
Results: The incidence of TB per 100,000 person-years was 339 in the cancer patients and 202 in the controls, which gives a crude incidence rate ratio of 1.68 (95%CI 1.42-1.98). The hazard ratio (HR) was 1.67 (95%CI 1.42-1.96) after adjusting for age, sex and comorbidity. Cox regression showed that cancers of the aerodigestive tract, including oral, nasopharyngeal and oesophageal and lung cancer (HR 3.09, 95%CI 2.42-3.94) and haematological cancers, including non-Hodgkin's lymphoma and leukaemia (HR 3.22, 95%CI 1.98-5.22), were significant risk factors for TB.
Conclusion: Cancer patients have a higher incidence of TB than controls. Patients with aerodigestive tract, lung and haematological cancers are especially vulnerable to TB.