Radiation exposure as a possible etiologic factor in hairy cell leukemia (leukemic reticuloendotheliosis).

The frequency of prior occupational, accidental, or therapeutic radiation exposure was significantly higher for hairy cell leukemia patients than for a control group of solid tumor patients (8/23 vs. 4/56, P < 0.01). Hairy cell leukemia patients were also more frequently involved in occupations at high risk of radiation exposure such as chemist, engineer, physicist, and health care facility worker (7/23 vs. 4/56, P < 0.01). The observation that the incidence of thyroid disorders among hairy cell leukemia patients was also unusually high (5/23 vs. 2/56, P < 0.05) was interpreted as further indirect evidence of excessive radiation exposure. It appears that radiation exposure may be an important contribution factor in the development of some case of hairy cell leukemia.