Resection margins and prognosis in locally invasive thyroid cancer

Background Invasive thyroid cancer is rare, and the extent of surgery controversial. The purpose of this study was to present and evaluate therapeutic prognostic factors. Methods We conducted a retrospective single-center study of differentiated thyroid carcinoma invading the larynx, trachea, and/or esophagus treated surgically with macroscopic complete resection. Results Forty-six patients (average age, 57 years; average follow-up, 4 years) were included. Free margins (R0) were obtained for 22 of 46 (49%) and microscopic residual tumor was present after surgery (R1) for 24 (51%). Ten-year actuarial local control was 100% for R0 and 75% for R1 (p =.08). Five-year local control was lower for recurrent tumors versus inaugurally invasive disease (63% vs 87%; log-rank p =.011). Five-year and 10-year actuarial disease-specific survival (DSS) was correlated with preoperative distant metastases (100% and 87%, respectively, for M0 vs 68% and 34% for M1; p =.01). Conclusion A trend toward lower local control was observed for R1 versus R0. The morbidity of surgery should be weighed against the prognosis if metastases are present.