Effect of a second primary thyroid carcinoma on patients with head and neck squamous cell carcinoma.

BACKGROUND The purpose of this study was to characterize the timing, histology, and behavior of second primary thyroid carcinoma (SPTC) developing after a diagnosis of head and neck squamous cell carcinoma (HNSCC). METHODS We conducted a retrospective review of the Surveillance, Epidemiology, and End Results (SEER) 9 database. RESULTS Patients with HNSCC who develop SPTC die 1.6 times sooner than those without SPTC. This effect is only seen if SPTC presents >6 months after diagnosis of HNSCC. Models were adjusted for age, sex, year of diagnosis, and location of HNSCC. There was no effect of prior radiation therapy on either mortality rates or time to development of thyroid cancer in patients with SPTC. The type of thyroid carcinoma that developed was similar between cohorts. CONCLUSION The development of SPTC in patients with HNSCC results in decreased overall length of survival. © 2015 Wiley Periodicals, Inc. Head Neck 38: E890-E894, 2016.