| Abstract
| - During the 15 years from 1967 to 1981, 3, 162 patients with carcinoma of the head and neck were treated with radiation therapy. Among them, 262 patients (8.3%) developed two or more independent malignancies. There were 80 patients with prior cancer. The overall incidence of second malignancies in patients who had radiation therapy was 5.8%. The incidences were 8.9, 7.7, 5.2 and 1.7% of index cancer in the larynx, pharynx, oral cavity and paranasal sinus, respectively. Second primaries were observed in the head and neck (36%), digestive tract (35%), lung (19%) and the remaining 10% in other bodily sites. Of the 1, 486 patients who survived for five years or more after radiation therapy, only 10 (0.7%) developed second malignancies within the previous radiation field.
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