Increased risk of salivary gland tumors after low-dose irradiation.

<bold>Objective: </bold>To assess the risk of neoplastic development among persons exposed to scalp irradiation.<bold>Study Design: </bold>Historical cohort study initially; prospective follow-up subsequently.<bold>Method: </bold>Two control groups--population and siblings--matched for age, sex, ethnic origin, and year of immigration. Follow-up from time of irradiation (1950s) until the end of 1991. Linkage with nationwide cancer registry.<bold>Results: </bold>A 4.5-fold incidence of cancer (P < .01) and a 2.6-fold increase of benign tumors were noted. The mean length of latency period until tumor development was 11 years for malignant tumors and 21.5 years for benign. A clear dose response effect for both cancer and benign tumors was demonstrated.<bold>Conclusions: </bold>The study confirms the role of radiation in salivary gland carcinogenesis. It indicates a need for better awareness, a comprehensive examination, and long-term follow-up of patients who have been subjected to head and neck radiation. [ABSTRACT FROM AUTHOR]