Clinical Behavior and outcome of papillary thyroid cancers smaller than 1.5 cm in diameter: Study of 299 cases

To investigate predictors of relapse in small (less than or equal to1.5 cm) papillary thyroid cancers, we performed a retrospective chart review study of patients treated and followed up in our institution according a standard prospective protocol. Between 1975 and 2001, 299 patients were operated for a differentiated papillary thyroid cancer no larger than 1.5 cm in size. Near-total or total thyroidectomy was performed in 292 patients, and lobectomy in seven patients. Persistent/recurrent disease was observed in 77 patients; in 37 of these patients, the only sign was increased TSH-stimulated serum thyroglobulin (Tg). Ten patients developed distant metastases, and 68 locoregional metastases. At multivariate analysis, persistent/recurrent disease was associated with: 1) nonincidental thyroid cancer; 2) lymph node metastases at presentation; and 3) bilateral tumor. Development of distant metastases was associated with the sclerosant variant and the presence of lymph node metastases at presentation. Tumor size (less than or equal to1.0 cm vs. 1.1-1.5 cm) was not predictive of relapse. No patient died because of the disease, but 14.4% had evidence of disease at their last follow-up visit. Serum Tg level below 1.0 ng/ml at the first postsurgical evaluation during L-T(4) withdrawal was an accurate predictor of no relapse. In conclusion, approximately one of four patients with a papillary thyroid cancer no more than 1.5 cm in size develops relapsing/persisting disease after surgery. Baseline histopathological characteristics and serum Tg levels off L-T(4) at first postsurgical evaluation can accurately predict the risk of relapse.