Geographical pathology as a method for detecting occupational cancer.

Geographical pathology points to environmental factors in cancer and helps estimate their potential magnitude. An occupational contribution was established by 1972 for cancer of the mouth, lung, bladder, and skin. Additionally partly based on geographical pathology, an occupational etiology is accepted for some cancer of nasopharynx, brain, liver, pleura, nasal sinus, bone and bone marrow, and possibly stomach. For identifying new occupational factors based on geographical comparisons, both an optimal size of work force to be followed-up and a sufficiently high proportion of work force in the geographical unit's population are necessary. Hypothetical variations based on 30-year follow-up of asbestos workers illustrate this. Cancer surveys and registries can greatly facilitate detection of occupational cancer. Evidence for occupational factors in the geographical pathology of lymphosarcoma is briefly summarized; but no conclusions are reached.