Novel analysis of prognosis of young patients with stage II differentiated thyroid cancer based on AJCC 8.0 and 6.0 criteria to implement the staging system

Abstract

Background: The incidence of thyroid cancer among young adults is increasing; however, the clinical challenges specific to this population, such as diagnosis, reduced healthcare access, and inconsistent care, have received limited attention. Here, we conducted a subgroup analysis on a series of relatively young patients with differentiated thyroid carcinomas (DTCs), focusing on those with distant metastases at stage II, to obtain a deeper understanding of the factors influencing survival.Methods: Information on <45-or <55-year-old patients at any T/N stage with distant metastasis (M1) was extracted from the SEER database according to the staging system in the 6 th and 8 th American Joint Committee on Cancer (AJCC) editions, respectively. Patient mortality was evaluated using Cox proportional hazards regression analyses and Kaplan-Meier analyses with log-rank tests.Results: Both cancer-specific and all-cause mortality rates per 1,000 person-years for patients ≥35 years old significantly differed from those of patients <35 years old. DTC-specific survival curves also significantly differed between these age groups, according to both the AJCC 6.0 and 8.0-based analyses (P=0.0017 and P<0.001, respectively), as did patient survival curves (P=0.0003, P<0.001, respectively). The multivariate Cox regression model also revealed that poor OS was strongly predicted by race (P<0.001) in the analysis based on the criteria of 8 th AJCC staging system.Conclusions: Age is a risk factor for disease-specific and overall survival (OS) in young patients with stage II DTC, and young male patients exhibited poorer survival than females. Race also emerged as a potential risk factor for young patients in stage II. These findings offer guidance for improving the older and newer versions of the AJCC staging system.