Water-related carcinomas: Environmental classification

Water-related cancers may be classified in four groups, which correspond closely and naturally with those used by Bradley for the classification of water-related communicable disease: (1) waterborne cancers induced by ingestion or inhalation of carcinogens present in drinking water (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 associated with Helicobacter pylori infection); (3) water-based cancers associated with helminthiases (bladder cancer due to Schistosoma haematobium infection; colorectal cancer associated with S. japonicum (possibly also S. mansoni) infection; bile duct cancer associated with Opisthorchis viverrini and Clonorchis sinensis infection); and (4) water-related insect vector cancers associated with a water-related insect vector communicable disease (Burkitt's lymphoma when associated with malaria infection). Caution should be exercised, however, when using such a classification: definition of a particular cancer as water related does not mean that all cases of such cancer are water related, but only that some cases may be water related.