Non-pulmonary cancer risk following TB: a nationwide retrospective cohort study in Lithuania
Abstract
Background
Lithuania remains one of
the highest tuberculosis burden countries in Europe.
Epidemiological studies have long pointed to infections as
important factors of cancer aetiology, but the association
between tuberculosis and the risk of non-pulmonary cancers has
rarely been tested and results have been inconsistent. The aim
of this population-based cohort study was to examine the risk of
cancer among patients diagnosed with tuberculosis using data
from Lithuanian Tuberculosis, Cancer and Resident’s
Registries.
Methods
The study cohort included
21,986 tuberculosis patients yielding 1583 cancers diagnosed
during follow-up (1998–2012). Standardized incidence
ratios (SIRs) and 95% confidence intervals (95% CIs) were
calculated to compare the incidence of cancer among cohort
participants with the general population for overall,
non-pulmonary, site-specific cancers, as well as for subgroups
of smoking-related, alcohol-related, hormone-related and
haematological cancers.
Results
The SIRs of all cancers
combined were 1.89, 95% CI: 1.79–2.00 in men and 1.34, 95%
CI: 1.19–1.50 in women. Risk was increased 3-fold within
the first year following diagnosis; it decreased during later
years, although remained significantly elevated for ≥5 years.
Elevated long-term increased risks persisted for non-pulmonary
cancers overall, and for cancers of mouth and pharynx,
oesophagus, stomach, larynx, cervix uteri and leukaemias.
Tuberculosis was associated with a decreased risk of melanoma.
Increased risks were observed for smoking-related cancers in men
(SIR 1.95, 95% CI: 1.79–2.13) and women (SIR 1.46, 95% CI:
1.22–1.73), alcohol-related cancers in men (SIR 2.40; 95%
CI: 2.14–2.68) and haematological cancers in men (SIR
1.73, 95% CI: 1.33–2.23). The risk of hormone-related
cancers was 18% lower (SIR = 0.82, 95% CI: 0.66–0.997)
among women, the inverse association was weaker among men (SIR =
0.95, 95% CI: 0.84–1.07).
Conclusions
The risk of total and
several non-pulmonary cancers was elevated in a cohort of
tuberculosis patients. The recommendation for the awareness of
this association among physicians is warranted. Analysis
suggests a reduction in risk of hormone-related cancers and
melanoma.
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Source:
Infectious Agents and Cancer
