Gastric and colorectal cancer in the rural Indian subcontinent: a survey of patients attending mission hospitals.

37 missionaries working in India, Nepal, Pakistan, Bangladesh and Bhutan completed questionnaires regarding their clinical practice during the year 1980. Information was collected on the frequency of both gastric and colorectal cancers. More than 500,000 out-patients were reviewed and over 100,000 inpatients treated. A total of 291 gastric tumours and 169 colorectal carcinomas were diagnosed. Surgery was performed in 82% of the hospitals but only 36% had a histology service. In India and Pakistan there was no significant difference between the incidence of gastric and colorectal neoplasms. The relative risk of developing gastric rather than colorectal cancer in Bangladesh was 8 (95% confidence limits 4.5-14.2) and in Nepal the relative risk was 4 (95% confidence limits 2.0-7.0). A significant variation in the occurrence of cancer was observed between countries. Nepal had the highest and Pakistan the lowest numbers of both gastric and colorectal tumours. It seems likely that local environmental factors, such as diet, play a significant role in the development of these tumours.