Epidemiology of gallbladder cancer in India.

India is a high incidence area for gallbladder cancer (GBC) and contributes to about 10% of the global GBC burden. Within India, the incidence is high in North, North-East, Central and Eastern India, and less common in South and West India. The incidence has been on a steady rise in both genders. The presentation is often with advanced disease and carries dismal prognosis. GBC in India usually affects younger patients in the 5th and 6th decade in contrast to the west. Gallstones are present in 80% of the Indian patients with GBC and its presence increases the vulnerability of the GB to mucosal injury. The incidence of GBC is out of proportion to the prevalence of gallstones in the country. Additional co-factors such as older age, lower socio-economic status, chronic Salmonella typhi (S. typhi) infection, Helicobacter pylori (H. pylori) infection, exposure to pollutants, heavy metals, chemicals, adulterated mustard oil and smoking in patients with gallstones have been identified which promote carcinogenesis. These risk factors act in tandem in an additive manner resulting in higher incidence of GBC as well as hasten the development of GBC. Environmental risk factors such as soil and water contamination by industrial wastes, agricultural effluents and human sewage have been identified as putative risk factors. Combination of a toxic environment, vulnerable GB and a susceptible host play a key role in the pathogenesis of GBC in the country. Large multicentric comprehensive studies are required in India to assess the attributable risk of each of the identified putative risk factors. This will help in formulating cost effective national strategies in preventing GBC related mortality in the country. Meanwhile a high index of suspicion to pick up incidental GBC, and improved access to healthcare facilities to manage GS appropriately will help in reducing GBC related mortality.