Hypothyroidism incidence after multimodality treatment for stage III and IV squamous cell carcinomas of the head and neck

Purpose: Treatment of head-and-neck cancer patients with surgery, radiother apy (RT), and chemotherapy has been associated with posttherapy hypothyroid ism (HT). We evaluated the rate of posttherapy HT in patients with locally advanced squamous cell carcinoma of the head and neck, treated with multimo dality therapy to determine which factors might predict this condition and at what interval the condition developed. Methods: We reviewed the prospectively collected thyroid function data of p atients treated with sequential chemotherapy, RT, and neck dissection. The incidence of posttherapy HT was estimated. The patients tumor, and treatmen t factors possibly associated with HT were evaluated. Results: Of 203 patients, 118 had data adequate for evaluation. HT develope d in 45% at a median of 24.4 months after therapy. HT occurred in 14% and 2 7% of patients at 6 months and 1 year after treatment, respectively. Univar iate and multivariate analyses of sex, age, RT dose, RT fractionation, T an d N stage, tumor site, and neck dissection failed to identify a clinically relevant risk factor. Conclusions: A high number of patients undergoing aggressive organ-sparing multimodality therapy for advanced squamous cell carcinoma of the head and neck are at risk for subsequent HT. We recommend that all patients definiti vely irradiated to the head and neck region undergo frequent serum thyroid- stimulating hormone screening for HT, beginning 6 months after RT. (C) 2001 Elsevier Science Inc.