Tumor Characteristics and Cardiovascular Mortality in 19,228 Thyroid Cancer Patients: A Population-Based Competing Risk Study

The association between tumor characteristics and cardiovascular mortality in thyroid cancer (TC) remains poorly characterized. We identified 19,228 primary TC patients from SEER (2004–2015), with follow-up through 2020. Fine–Gray and cause-specific Cox models evaluated cardiovascular disease (CVD) mortality, with analyses by sex and age. A nomogram was developed for exploratory risk stratification, and separate continuous-age competing-risk models were assessed in training and validation cohorts. During a median follow-up of 8.3 years, 321 (18.7%) of 1713 deaths were CVD-related. Compared with localized disease, regional and distant stage were associated with higher cause-specific hazards of CVD death (csHR 1.32, 95% CI 1.03–1.71; and 2.46, 1.71–3.55, respectively). The distant-stage subdistribution association was elevated early after diagnosis and attenuated over follow-up (12-month sHR 2.79, 95% CI 1.61–4.83). Male sex was associated with a higher overall subdistribution hazard (sHR 2.19, 95% CI 1.73–2.78). The prediction model yielded validation AUCs of 0.854–0.895 at 5–10 years, but adding stage did not meaningfully improve five-year prediction beyond the baseline models evaluated. These findings support attention to cardiovascular risk at TC diagnosis and during survivorship, taking tumor stage, conventional risk factors and planned treatment into account.