Risk Factors and Outcomes of Postoperative Recurrent Well-Differentiated Thyroid Cancer: A Single Institution's 15-Year Experience.

Objective Identify risk factors and outcomes of recurrent well-differentiated thyroid cancer. Study Design Retrospective case-control analysis. Setting Tertiary care academic center in Nashville, Tennessee. Subjects and Methods This single-center analysis reviews 478 patients who underwent initial surgical management of well-differentiated thyroid carcinoma between 2002 and 2017. Patients were dichotomized with or without recurrent well-differentiated thyroid cancer. Demographic and clinicopathologic risk factors were carefully reviewed. Univariate, multiple regression, and survival analyses were used to evaluate predictors of recurrence. Results Thirty-eight patients (7.9%) who received initial surgical intervention for well-differentiated thyroid carcinoma at our institution recurred, with an average time to recurrence of 24 months. Male sex, tumor size, multifocality, extrathyroidal extension, lymphovascular invasion, number of positive lymph nodes, and low lymph node yield were all significantly associated with locoregional recurrence (P < .05). Multiple regression analysis showed that extrathyroidal extension, number of positive lymph nodes, and low lymph node yield were independent factors predictive of posttreatment recurrence (P < .05). Metastatic lymph node ratio, the ratio of positive lymph nodes extracted to lymph node yield, of >= 0.3 is associated with increased risk of recurrence (P < .001) and decreased 5-year recurrence free survival (P < .001). Conclusion Extrathyroidal extension, number of positive lymph nodes, and low lymph node yield are independent clinicopathologic risk factors for postoperative recurrence of well-differentiated thyroid cancer. Metastatic lymph node ratio is uncommonly used but can be an important prognosticator of recurrence. Patients with metastatic lymph node ratio >= 0.3 should be counseled on their increased risk of recurrence and should undergo close surveillance following surgery.