MeSS: A novel prognostic scale specific for pediatric well-differentiated thyroid cancer: A population-based, SEER outcomes study

Background. High-risk prognostic factors for adults with Well-differentiated thyroid cancer (WDTC) have been well established, but the same is not true for pediatric patients. This study sought to determine whether validated adult prognostic systems are applicable to pediatric patients and to develop a novel prognostic Scale that may better reflect outcomes in pediatric subgroups. Methods. We queried 62,007 cases of WDTC from the Surveillance, Epidemiology, and End Results (SEER) database (1973-2009) to identify 895 patients <20 years of age with WDTC. Data abstracted included age, gender, race, histology type, primary tumor size, cancer stage, and mortality. Odds ratio and 95% confidence intervals were set and data were analyzed with SAS version 9.2. Results. Among 895 pediatric WDTC patients, the overall cause-specific mortality was 0.8%. The presence of distant metastasis was associated with the worst prognosis (P=.0045) followed by larger primary tumor size (P=.0135) and male gender (P=.0162). When classified into low-, moderate-, and high-risk categories according to the distant metastasis (Me), larger primary tumor size (S), and male sex (S) (MeSS) algorithm, mortality rates were 0%, 2.7%, and 23%, respectively. Conclusion. Commonly used prognostic indices for WDTC in adults do not reliably predict poor outcomes among pediatric patients. Rather, a system based on MeSS is more applicable to pediatric patients. Patients who exhibit a high MeSS score have a significantly worse overall survival than those who do not express any MeSS characteristics.