Salmonella typhi and gallbladder cancer

Abstract

This chapter reviews the current epidemiological indicators suggesting that Salmonella typhi could be a causal agent of gallbladder cancer (GBC). Both GBC and S. typhi occur in poor areas and are frequent in some Latin American (Chile, Mexico) and Asian (India, Korea) countries. In the developed world, typhoid or GBC are seen mainly among travelers or immigrants. While most people are susceptible to S. typhi infection, only 3% of infected become chronic carriers of S. typhi in their biliary tract. Gallstone carriers have a 6-15 times higher risk of becoming S. typhi carriers (Hofmann and Chianale, J Infect Dis, 167(4):993-994, 1993). S. typhi chronic carriers have 3-200 times higher risk of GBC than non-carriers, and 1-6% lifetime risk to develop GBC (Caygill et al., Lancet 343(8889):83-84, 1994; Eur J Cancer Prev 4(2):187-193, 1995). S. typhi associated relative risk of GBC is higher than that for gallstones (GS) alone; GS carriers have OR from 3 to 6 and less than 1% lifetime risk to develop GBC (Hsing et al., Biliary tract cancer. In: Schottenfeld D, Fraumeni JF (eds) Cancer epidemiology and prevention, 3rd edn. Oxford University Press, New York, pp. 787-800, 2006; Pandey, J Surg Oncol 93(8):640-643, 2006; Diehl, JAMA 250(17):2323-2326, 1983). The major steps in gallbladder carcinogenesis would be: S. typhi acute infection, S. typhi persistence as a chronic infection for decades, latency of 10 years to progress from metaplasia or dysplasia to pre cancer, and 5 years latency for invasion. Mechanistic research is needed to understand S. typhi-GBC association and provide tools for its control. Nevertheless, with the current epidemiological evidence much suffering could be prevented by: (i) health education, basic sanitation and food hygiene, to interrupt S. typhi transmission; (ii) treatment of chronic carriers, (iii) promotion of healthy diet and lifestyles to prevent gallstone formation, and (iv) cholecystectomy of gallstone disease in high risk areas to prevent invasive GBC.