Ten-year outcome of papillary thyroid carcinoma, the efficacy of risk stratification systems in predicting long-term adverse outcomes.

Abstract

Background: Papillary thyroid cancer has an established favorable outcome with a 10-year overall survival of more than 90%, but the chances of recurrences are as high as 20%. Traditionally, all intermediary-risk and high-risk category patients undergo vigorous follow-up. A sensitive risk stratification system may predict the patients requiring stringent postoperative surveillance.

Methods: The present study is a retrospective cohort study of papillary thyroid cancer operated and systematically followed for a median period of 135.5 months. The outcomes at the end of the follow-up period were determined based on American Thyroid Association (ATA) guidelines (2015). We used American Joint Committee on Cancer (AJCC) risk stratification (8 th edition), ATA risk stratification (2015), and a modified dynamic risk stratification system. The disease status in the first year of the follow-up was used for reclassification.

Results: The overall survival was 95.1%, but the incidence of adverse outcomes which included disease-specific mortality, structural incomplete responses, and biochemical incomplete responses was 11.2% (n: 23). The modified dynamic risk stratification had higher accuracy in predicting the outcomes.

Conclusion: Patients who had excellent responses in the first year of follow-up are unlikely to develop adverse events in the future. However, those who had overt or evident distant metastases at the time of diagnosis require vigilant surveillance.