Postoperative irradiation for thyroid cancer.

The place of external irradiation for thyroid cancers remains controversial. Between 1974 and 1989, 94 patients with a differentiated thyroid cancer were seen in our department for additional treatment (radioiodine with or without external radiation) after a surgical resection. 56 patients were treated with radioiodine alone and 38 patients had an additional course of external radiation. Survival was identical for the two groups but the local relapse rates were 21% and 3% respectively. So, in this retrospective study, the addition of external radiation appears to improve the local control especially in the case of an incomplete surgical resection or extracapsular tumor extension. This benefit was achieved without severe radiation-induced late effects.