Phase II Clinical Trial of Intravenous Levothyroxine to Mitigate Pharyngocutaneous Fistula in Euthyroid Patients Undergoing Salvage Laryngectomy.

Abstract

Patients undergoing head and neck cancer surgery after prior radiation or chemoradiation are at high risk for wound complications. Hypothyroidism is a known risk factor for wound complications, especially fistulae after salvage total laryngectomy. The purpose of this phase II clinical trial is to investigate the effect of peri-operative intravenous levothyroxine supplementation on wound complications in patients undergoing salvage total laryngectomy. Euthyroid patients previously treated with radiation/chemoradiation undergoing total laryngectomy were prospectively recruited (n=72). Post-operatively, intravenous levothyroxine was administered at a weight-based dose (1.3 mcg/kg/day) and transitioned to enteral dosing on day 7. Free T3, T4, and thyroid stimulating hormone (TSH) were collected and dosing was adjusted accordingly. The primary endpoints were rates of fistula and fistula requiring re-operation, compared to matched historical controls. All patients were monitored for adverse effects. The rate of post-operative hypothyroidism was 21% compared to 49% in a matched historic cohort. The rate of fistula was 18.1% while the rate of fistula requiring re-operation was 4.2%, significantly lower than rates in our historic cohort (34.6% and 14.8% respectively, p=0.02 and 0.01). Post-operative hypothyroidism and recurrent clinical stage predicted fistula requiring re-operation in multivariate analysis; other acute phase reactants were not predictive. There were no observed adverse events related to levothyroxine supplementation. Post-operative intravenous levothyroxine supplementation reduced rates of acute hypothyroidism, fistula, and fistula requiring re-operation in patients undergoing salvage total laryngectomy without adverse effects. Intravenous levothyroxine is a viable strategy to reduce wound complications in this high-risk patient population.