Late effects among young thyroid cancer survivors

111 Background: Thyroid cancer is the most rapidly increasing cancer with over 600,000 thyroid cancer survivors in the U.S. Thyroid cancer affects a young population and the 5-year survival rate is over 98%. There have been few studies on the late effects of thyroid cancer, especially in younger populations. The aim of this study was to examine if thyroid cancer survivors diagnosed < 40 years experience greater risks of late effects than older age groups for diseases associated with aging. Methods: Up to 5 cancer free individuals were matched to each thyroid cancer survivor based on birth year, sex, birth state, and follow up time from case diagnosis date, within the Utah Population Database. Electronic medical records, statewide ambulatory surgery and inpatient discharge data were used to identify late effects stratified over three time periods: 1-5, 5-10, and > 10 years after cancer diagnosis. Cox proportional hazards models were used to estimate hazard ratios (HR) with adjustment on matching factors, race, BMI at diagnosis, and Charlson Comorbidity Index at diagnosis. Results: There were 4,060 thyroid cancer survivors and 18,557 matched cancer free individuals (1,407 cases diagnosed ages < 40 years, 2,076 cases diagnosed ages 40-65 years). The risk for hypertension was significantly increased in both younger (HR = 1.54, 95%CI = 1.18, 2.01) and older patients (HR = 1.30, 95%CI = 1.11, 1.53) > 10 years after cancer diagnosis. For heart disease, increased risks persisted for the young patients > 10 years after cancer diagnosis for heart valve disorders (HR = 2.43, 95%CI = 1.36, 4.33) and for peri-, endo- or myocarditis (HR = 5.12, 95%CI = 1.04, 25.14), while corresponding HRs for the older age group did not suggest increased risks. For osteoporosis, the younger patients had a higher risk (HR = 8.77, 95%CI = 3.18, 24.18) than the older population (HR = 2.55, 95%CI = 2.07, 3.13) 1-5 years after cancer diagnosis. Conclusions: Thyroid cancer survivors diagnosed at < 40 years had increased risks for diseases associated with aging such as hypertension, heart disease, and osteoporosis. As thyroid cancer affects a young population, understanding what late effects may result from the treatment can lead to better surveillance and disease management.