Cancer incidence attributable to tuberculosis in 2015: global, regional, and national estimates.

Background: Tuberculosis is associated with increased risk of cancer. However, the impact of tuberculosis on global cancer burden is unknown.

Methods: We performed random-effects meta-analyses and meta-regressions of studies reporting the association between tuberculosis and cancer risks by searching PubMed, Web of Science, Embase, Cochrane library, and CINAHL from inception to 1 June 2019. Population attributable fractions (PAFs) of cancer incidence attributable to tuberculosis were calculated using relative risks from our meta-analyses and tuberculosis prevalence data from Global Health Data Exchange by age, sex, and country. The study has been registered with PROSPERO (CRD42016050691).

Results: Fourty nine studies with 52,480 cancer cases met pre-specified inclusion criteria. Tuberculosis was associated with head and neck cancer (RR 2.64[95% CI 2.00-3.48]), hepatobiliary cancer (2.43[1.82-3.25]), Hodgkin's lymphoma (2.19[1.62-2.97]), lung cancer (1.69[1.46-1.95]), gastrointestinal cancer (1.62[1.26-2.08]), non-Hodgkin's lymphoma (1.61[1.34-1.94]), pancreatic cancer (1.58[1.28-1.96]), leukaemia (1.55[1.25-1.93]), kidney and bladder cancer (1.54[1.21-1.97]), and ovarian cancer (1.43[1.04-1.97]). We estimated that 2.33%(1.14-3.81) or 381,035(187145-623,404) of global cancer incidences in 2015 were attributable to tuberculosis. The PAFs varied by Socio-demographic Index (SDI)-ranging from 1.28% (0.57-2.31%) in the high-SDI countries to 3.51% (1.84-5.42%) in the middle-SDI countries. Individually, China and India accounted for 47% of all tuberculosis-related cancer cases.

Conclusions: Tuberculosis is associated with increased risk of cancer at ten sites. The burden of tuberculosis attributable cancer skewed towards lower resource countries. Research priorities are to better understand regional disparities and underlying mechanism linking tuberculosis and cancer development.