Background: Gastrectomy for peptic ulcers and chemotherapy for malignancy are known risk factors for tuberculosis (TB). However, this relationship has rarely been investigated in patients with gastric cancer.
Methods: In a retrospective cohort study from 2000 to 2006, data for 2215 patients diagnosed with gastric cancer at our hospital were compared with data from the Centers for Disease Control (CDC), Taiwan, to identify confirmed cases of TB.
Results: In patients with gastric cancer without a history of gastrectomy and without previous anti-TB treatment, the overall crude incidence of new-onset TB was 788 per 100,000 person-years. Compared with the general population, the overall age-sex standardized incidence (SI) in gastric cancer patients was 134.3 (SI ratio [SIR]: 2.11, p < 0.05), and the recurrence rate among patients with previous anti-TB treatment was 18% (4/22) after gastric cancer diagnosis. Gastrectomy was a significant risk factor for active TB incidence [SI 159 (95% confidence interval [CI], 80-237, SIR: 2.5, p < 0.05), and chemotherapy alone seemed to be a risk factor, but was without statistical significance (SIR: 12.5, p > 0.05). Multivariate analysis showed old age, male gender, previous anti-TB treatment, and gastrectomy as significant risk factors for TB. In stratified analysis, an interaction between old TB patterns on chest films and chemotherapy was observed.
Conclusions: Old age, male gender, previous anti-TB treatment, and gastrectomy were significant risk factors for TB. An increased risk of TB incidence after chemotherapy was observed in patients with old TB pattern chest films initially, suggesting an interaction between chest film patterns and chemotherapy.