Abstract:

Background and purpose: Thyroid cancer is the most common malignant endocrine tumor, particularly prevalent among the Asian population. The overall survival for thyroid cancer patients is relatively high, but there are significant survival differences among patients. Based on long-term hospital-based cancer registry database, this study analyzed the 10-year observed overall survival (OS) rate of thyroid cancer cases and the distribution of causes of death, providing real-world evidences to further survival management of thyroid cancer in China. Methods: A total of 55343 thyroid cancer patients who underwent treatment at Fudan University Shanghai Cancer center from 2005 to 2021 were included in this study. Clinical information and the follow-up endpoint data were collected through medical records review, telephone visits and death registry data linkage. The last follow-up date was October 31, 2024. Kaplan-Meier method was applied in evaluating the OS rate, and survival data were described by different subgroups as age group, gender, treatment period, tumor staging and pathological characteristics. The standardized mortality ratio (SMR) and absolute excess risk (AER) were calculated using general Shanghai population as the reference, and the mortality risk was described by gender, age at diagnosis and histological subtype. Results: With a median follow-up time of 63.01 months, the overall 1-, 3-, 5- and 10-year OS rates of thyroid cancer patients were 99.67% (95% CI: 99.62%-99.72%), 99.11% (95% CI: 99.03%-99.19%), 98.48% (95% CI: 98.36%-98.60%) and 95.81% (95% CI: 95.50%-96.11%), respectively. The 10-year OS rates of stage Ⅰ, Ⅱ, Ⅲ and Ⅳ were 97.99% (95% CI: 97.70%-98.28%), 89.80% (95% CI: 87.24%-92.37%), 77.84% (95% CI: 70.76%-84.92%) and 62.95% (95% CI: 55.37%-70.54%), respectively. The differences in OS among patients with different age, gender and histological classification were significant. 1256 (2.27%) deaths occurred, of which 18.63%, 50.88% and 7.32% were attributable to thyroid cancer, other cancers and cardiovascular disease (CVD), respectively. Compared with the general population, patients with different subtypes of thyroid cancer had higher all-cause mortality rates, progressively increasing with papillary, follicular, medullary and anaplastic thyroid carcinoma/poorly differentiated carcinoma. Compared with general population, the death risk was 2.24 times higher in papillary thyroid cancer patients (95% CI: 2.06-2.44), 9.94 times higher in follicular thyroid cancer patients (95% CI: 6.79-14.09), 12.16 times higher in medullary thyroid cancer patients (95% CI: 8.05-17.69), and the highest risk was observed in patients with anaplastic thyroid carcinoma/poorly differentiated carcinoma [SMR=79.67 (95% CI: 58.38-106.31), AER=766.01/1 000 person-years]. Conclusion: The 10-year long survival data and cause of death for thyroid cancer patients with different histological types were reported in China based on a large single institution hospital-based cancer registry database. Staging and histological characteristics were the most important factors directly affected the survival. Early diagnosis and individualized treatment are crucial for improving prognosis.

Key words: Thyroid cancer, Overall survival rate, Hospital-based registry, Cause-of-death analysis