Selective treatment of differentiated thyroid carcinoma.

Abstract

Over a period of 20 years 84 papillary and 82 follicular carcinomas operated on by one surgeon and examined by one pathologist were documented prospectively, treated selectively, and followed for 1 to 20 years (median 7 years). Tumors with a low risk of recurrence or incurable disease-i.e., papillary carcinoma pT1-3 N0 M0 (n = 56) and minimally invasive follicular carcinoma (n = 37)-were treated by a limited-radicality hemithyroidectomy or total thyroidectomy without radioiodine in 79 of the 93 cases (85%). No unfavorable course was observed, and only one curable recurrence (1.3%) developed contralaterally after hemithyroidectomy for papillary cancer. Of the remaining 73 patients, including 100% of those with nodal involvement, 65 (89%) underwent total thyroidectomy with radioiodine. Total thyroidectomy was achieved in 34% of the cases by completion thyroidectomy, based on definitive histologic examination. No instance of a serious, potentially incurable recurrence and no tumor-related death was observed in patients with a papillary TNM stage I+II or with a minimally invasive follicular carcinoma. Five of the patients (6%) with papillary carcinoma, all with TNM stage III or IV, and seven of the patients (8.5%) with follicular carcinoma, all grossly invasive and pT3 or pT4, had tumor-related deaths following total thyroidectomy in all and with remnant ablation in 10 cases. A potentially curable node recurrence occurred in two patients 1 and 10 years, respectively, after primary treatment. Permanent hypoparathyroidism (n = 4) (2.4%) and permanent recurrent laryngeal nerve palsy (n = 2) (1.2%) were observed only in patients with a grossly invasive follicular carcinoma and concomitant benign recurrent goiter. We conclude that (1) hemithyroidectomy or total thyroidectomy without radioiodine is adequate for papillary carcinoma pT1-3 N0 and minimally invasive follicular carcinoma; (2) there were no nodal recurrences in tumors recognized as node-negative; and (3) extracapsular excision of one or both lobes can be carried out technically with low morbidity. The study confirms the prognostic value of age-related TNM classification for papillary carcinoma; classification of follicular thyroid carcinoma as minimally invasive or grossly invasive proved to be useful.