Risk Factors That Influence Surgical Decision-Making for Patients with Low-Risk Differentiated Thyroid Cancer with Tumor Diameters of 1-4 cm

Background: There are several controversies between thyroid lobectomy and total thyroidectomy for surgical management of low-risk differentiated thyroid cancer (DTC) with a tumor diameter of 1-4 cm. Patients and Methods: In this study, we explore the factors related to selection of type of surgical procedure for 103 low-risk DTC patients with a tumor diameter of 1-4 cm. Results: Among 103 low-risk DTC patients with tumor diameters of 1-4 cm, 43 patients underwent total thyroidectomy and 60 patients underwent thyroid lobectomy based on postoperative pathology. A ROC curve showed that the optimal diagnostic threshold for selecting surgical modality was a tumor diameter of 2.15 cm. For these low-risk DTC patients, the sensitivity and specificity for predicting thyroid lobectomy when tumor diameter <2.15 cm while total thyroidectomy when tumor diameter >= 2.15 cm are 46.5% and 78.3%, respectively. There were significant differences between the selection of type of surgical procedure in patient groups with 1) tumors with multiple foci group vs a single focus (P<0.05), and 2) tumor diameter of >= 2.15 cm vs <2.15 cm (P 0.05). There was no significant difference between gender and age groups (P 0.05). Multivariate analysis confirmed that tumors with multiple foci and diameter >= 2.15 cm were the primary risk factors for implementation of total thyroidectomy (P<0.05). Conclusion: The diameter and multifocal nature of low-risk DTC tumors are the primary factors related to preferred surgical modality. This study revealed that thyroid lobectomy is more applicable to patients with tumor diameter <2.15 cm and a single focus, whereas, total thyroidectomy was preferred in patients with tumor diameter >= 2.15 cm and/or multiple foci.