INCREASED RISK OF SALIVARY-GLAND TUMORS AFTER LOW-DOSE IRRADIATION

Objective: To assess the risk of neoplastic development among persons exposed to scalp irradiation. Study Design: Historical cohort study in itially; prospective follow-up subsequently. Method: Two control group s-population and siblings-matched for age, sex, ethnic origin, and yea r of immigration. Follow-up from time of irradiation (1950s) until the end of 1991, Linkage with nationwide cancer registry. Results: A 4.5- fold incidence of cancer (P < .01) and a 2.6-fold increase of benign t umors were noted, The mean length of latency period until tumor develo pment was 11 years for malignant tumors and 21.5 years for benign. A c lear dose response effect for both cancer and benign tumors was demons trated. Conclusions: The study confirms the role of radiation in saliv ary gland carcinogenesis. It indicates a need for better awareness, a comprehensive examination, and long-term follow-up of patients who hav e been subjected to head and neck radiation.