Systematic review with meta-analysis: the relationship between chronic Salmonella typhi carrier status and gall-bladder cancer.

BACKGROUND: Carcinoma of the gall-bladder is the fifth commonest gastrointestinal tract cancer and is endemic in several countries. An association of chronic typhoid carriage and carcinoma of the gall-bladder has been reported.

AIM: To clarify whether chronic Salmonella typhi carrier state is associated with carcinoma of the gall-bladder.

METHODS: A systematic search was conducted using MEDLINE, PubMed, EMBASE, Current Contents, Cochrane library, Google Scholar, Science Direct and Web of Science. Original data were abstracted from each study and used to calculate a pooled odds ratio (OR) and 95% confidence interval (95% CI).

RESULTS: Of the articles selected, only 17 studies met full criteria for analysis. The overall OR for chronic S. typhi carrier state was 4.28(95% CI: 1.84-9.96). Most of the studies were from South Asia especially India and China. When a subgroup analysis was performed according to region, a significant association was observed in South-East Asia (OR: 4.13, 95% CI: 2.87-5.94, P value <0.01). Chronic S. typhi carrier state was associated with carcinoma of the gall-bladder based on detection methods of S. typhi antibody levels (OR: 3.52, 95% CI: 2.48-5.00, P value <0.01) and even more so on culture (OR: 4.14, 95% CI: 2.41-7.12, P value <0.01). The association was prominent in controls without gallstones (OR: 5.86, 95% CI: 3.84-8.95, P value <0.01) when compared with controls with gallstones (OR: 2.71, 95% CI: 1.92-3.83, P value <0.01).

CONCLUSIONS: Chronic S. typhi carrier state is an important risk factor among patients with carcinoma of the gall-bladder. Given the high risk associated with this carrier state, management options should include either elective cholecystectomy or careful monitoring using ultrasound.