The Role of Adjuvant Radiation Therapy for Locoregionally Advanced Papillary Thyroid Carcinoma

Objectives: To investigate the role of adjuvant radiation therapy in locoregional control in patients with locoregionally advanced papillary thyroid carcinoma (pT4 or pN1b) based on a comparison of a group that received radiation therapy and a group that did not receive radiation therapy. Methods: A retrospective analysis was performed on 165 patients with locoregionally advanced papillary thyroid carcinoma who underwent treatment between 2002 and 2011. Of these, 32 patients received adjuvant radiation therapy, and 133 patients did not receive radiation therapy. Results: The median follow-up period was 7.2 years (range, 3.4-13.6) for the overall study population. The 10-year locoregional recurrence-free survival rates for patients in the radiation therapy and no radiation therapy groups were 83.9 and 60.8%, respectively (p = 0.037). The overall survival rate and distant recurrence-free survival rate were not different between the two groups (p = 0.076 and p = 0.813, respectively). Multivariate analysis showed that adjuvant radiation therapy was an independent prognostic factor for locoregional recurrence-free survival (p = 0.040). Conclusions: Adjuvant radiation therapy for patients with either pT4 or pN1b disease improved locoregional recurrence-free survival and might be of benefit for patients with these high-risk features by reducing the need for additional salvage treatment after locoregional recurrence.