Purpose: Treatment of head-and-neck cancer patients with surgery, radiotherapy (RT), and chemotherapy has been associated with posttherapy hypothyroidism (HT). We evaluated the rate of posttherapy HT in patients with locally advanced squamous cell carcinoma of the head and neck, treated with multimodality 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 patients treated with sequential chemotherapy, RT, and neck dissection. The incidence of posttherapy HT was estimated. The patient, tumor, and treatment factors possibly associated with HT were evaluated.
Results: Of 203 patients, 118 had data adequate for evaluation. HT developed in 45% at a median of 24.4 months after therapy. HT occurred in 14% and 27% of patients at 6 months and 1 year after treatment, respectively. Univariate and multivariate analyses of sex, age, RT dose, RT fractionation, T and 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 definitively irradiated to the head and neck region undergo frequent serum thyroid-stimulating hormone screening for HT, beginning 6 months after RT.