Extent of surgery for intermediate-risk well-differentiated thyroid cancer

Background: Methods of assigning patients with papillary or follicular thyroid cancer (well-differentiated thyroid cancer) to risk groups for the purpose of determining appropriate therapy have been developed. Despite these efforts, the optimal extent of surgery for intermediate-risk patients remains controversial. Methods: A retrospective study was conducted of 208 patients with well-differentiated thyroid cancer (DTC) from two institutions. Univariate and multivariate analysis of patient- and tumor-related variables was performed. A regression model was obtained, three risk groups (low, intermediate, and high) were defined, and survival curves were generated. Results: Prognostic variables were age (P <0.001), distant metastases (P <0.001), tumor size (P <0.001) and an aggressive growth pattern (P = 0.03) by univariate analysis and age (P <0.001) and distant metastases (P <0.001) by multivariate analysis. Tumor size (P = 0.07) was included in the regression model. Total thyroidectomy appeared to provide a survival advantage for intermediate risk patients. High-risk patients treated by lobectomy had a poorer prognosis. Conclusions: Total thyroidectomy may provide a survival advantage for intermediate-risk patients with DTC. A prospective randomized trial with 200 such patients is required to confirm this finding.