[Thyroid cancer induced by radiotherapy. Clinico-anatomopathological comparison with spontaneously occurring cancer]

Thirty-three patients with thyroid cancer following irradiation of head, neck and chest were compared to 389 patients, with the same kind of cancer, who had not undergone irradiation therapy. The two groups showed a different distribution of different isotypes. In group 1 (following irradiation) the papillary isotype was most common in a much greater number of cases than in group 2. Lymph nodes metastases had a higher incidence rate in group 1. There was no significant difference as far as the histologic sub-groups associated with thyroid cancer were concerned. The results of the study were not altered by any such factor as age, which does usually modify the distribution of the isotypes.