Extent of surgery affects survival for papillary thyroid cancer

Background: The extent of surgery for papillary thyroid cancers (PTC) remains controversial. Consensus guidelines have recommended total thyroidectomy for PTC >= 1 cm; however, no study has supported this recommendation based on a survival advantage. The objective of this study was to examine whether the extent of surgery affects outcomes for PTC and to determine whether a size threshold could be identified above which total thyroidectomy is associated with improved outcomes. Methods: From the National Cancer Data Base (1985-1998), 52,173 patients underwent surgery for PTC. Survival was estimated by the Kaplan-Meier method and compared using log-rank tests. Cox Proportional Hazards modeling stratified by tumor size was used to assess the impact of surgical extent on outcomes and to identify a tumor size threshold above which total thyroidectomy is associated with an improvement in recurrence and long-term survival rates. Results: Of the 52,173 patients, 43,227 (82.9%) underwent total thyroidectomy, and 8946 (17.1%) underwent lobectomy. For PTC < 1 cm extent of surgery did not impact recurrence or survival (P = 0.24, P = 0.83). For turnors >= 1 cm, lobectomy resulted in higher risk of recurrence and death (P = 0.04, P = 0.009). To minimize the influence of larger tumors, 1 to 2 cm lesions were examined separately: lobectomy again resulted in a higher risk of recurrence and death (P = 0.04, P = 0.04). Conclusions: The results of this study demonstrate that total thyroidectomy results in lower recurrence rates and improved survival for PTC >= 1.0 cm compared with lobectomy. This is the first study to demonstrate that total thyroidectomy for PTC >= 1.0 cm improves outcomes.