RESUMO
PURPOSE: 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. PATIENTS AND METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.
RESUMO
BACKGROUND: Patients undergoing salvage laryngectomy are predisposed to radiation-induced hypothyroidism and impaired wound healing secondary to the tissue effects of prior treatment. The impact of hypothyroidism on postoperative wound healing is not established. METHODS: A single-institution retrospective case series was performed. The inclusion criteria specified preoperatively euthyroid adults who underwent salvage laryngectomy with concurrent neck dissection between 1997 and 2015 for persistent or recurrent laryngeal squamous cell carcinoma after radiation or chemoradiation therapy (n = 182). The principal explanatory variable was postoperative hypothyroidism, defined as thyroid-stimulating hormone (TSH) higher than 5.5 mIU/L. The primary end points of the study were pharyngocutaneous fistulas and wounds requiring reoperation. Multivariate analysis was performed. RESULTS: The fistula rate was 47% among hypothyroid patients versus 23% among euthyroid patients. In the multivariate analysis, the patients who experienced hypothyroidism in the postoperative period had a 3.6-fold greater risk of fistula [95% confidence interval (CI) 1.8-7.1; p = 0.0002]. The hypothyroid patients had an 11.4-fold greater risk for a required reoperation (24.4 vs 5.4%) than the euthyroid patients (95% CI 2.6-49.9; p = 0.001). The risk for fistula (p = 0.003) and reoperation (p = 0.001) increased with increasing TSH. This corresponds to an approximate 12.5% incremental increase in the absolute risk for fistula and a 10% increase in the absolute risk for reoperation with each doubling of the TSH. CONCLUSION: Postoperative hypothyroidism independently predicts postoperative wound-healing complications. The association of hypothyroidism with fistula formation may yield opportunities to modulate wound healing with thyroid supplementation or to provide a biomarker of wound progression.
