Late recurrence of cancer in the larynx and hypopharynx after irradiation.

11 cases of recurrent laryngeal or hypopharyngeal carcinoma, occurring 5 or more years after radiotherapy for carcinoma, are reported. The possible pathological mechanisms involved include persistence of the original carcinoma, second primary due to the original factors, and radiation-induced carcinoma. The last-mentioned possibility is of vital importance and requires further investigation. If radiation-induced carcinoma is as common as some recent series suggest, then primary treatment of T1 laryngeal carcinoma must be re-thought. However, this author believes that convincing evidence is lacking that irradiation is a common cause of late recurrent carcinoma.