WATER-RELATED CARCINOMAS - ENVIRONMENTAL CLASSIFICATION

Water-related cancers may be classified in four groups, which correspo nd closely and naturally with those used by Bradley for the classifica tion of water-related communicable disease: (1) waterborne cancers ind uced by ingestion or inhalation of carcinogens present in drinking wat er (for example, arsenic-induced skin and radon-induced lung cancer); (2) water-washed cancers due to the use of inadequate volumes of water for personal and domestic hygiene (penile carcinoma; gastric cancer a ssociated with Helicobacter pylori infection); (3) water-based cancers associated with helminthiases (bladder cancer due to Schistosoma haem atobium infection; colorectal cancer associated with S. japonicum (pos sibly also S. mansoni) infection; bile duct cancer associated with Opi sthorchis viverrini and Clonorchis sinensis infection); and (4) water- related insect vector cancers associated with a water-related insect v ector communicable disease (Burkitt's lymphoma when associated with ma laria infection). Caution should be exercised, however, when using suc h a classification: definition of a particular cancer as water related does not mean that all cases of such cancer are water related, but on ly that some cases may be water related.