Recent developments in radiation-induced carcinoma of the thyroid.

At the University of Chicago Hospitals, 40 per cent of patients with a history of irradiation to the neck and a palpable thyroid abnormality have been found recently to have carcinoma of the thyroid at operation. In a study of 100 unselected patients with a history of neck irradiation, 26 had palpatory abnormalities and seven of 15 who were operated upon had carcinoma of the thyroid. Five of these lesions demonstrated evidence of local invasion or lymph node metastases. This prevalence rate of carcinoma of at least 7 per cent in irradiated patients is the highest yet reported. These facts have led us to take a very aggressive position in the treatment of these patients. All patients must be examined carefully. When any palpatory abnormality is present which cannot be explained convincingly by thyroiditis, the patient should be operated upon. Total or near-total thyroidectomy should be performed in each patient by a qualified neck surgeon. In cases of proved carcinoma, a modified radical neck dissection should be added if cervical lymph nodes are clinically involved with tumor. Postoperative thyroid hormone suppression is mandatory and ablation of any residual iodine uptake in the neck or elsewhere by radioactive iodine is advocated. If treatment is aggressive, an excellent prognosis can be expected. However, deaths do occur from this disease. It is imperative that each of us be aware of this disease entity and that we treat these irradiated patients appropriately.