Evaluating Disease Specific Survival Prediction of Risk Stratification and TNM Systems in Differentiated Thyroid Cancer


 
 
 Many countries have national guidelines for the management of differentiated thyroid cancer (DTC), including a risk stratification system to predict recurrence of disease. Studies whether these guidelines could also have relevance, beyond their original design, in predicting survival are lacking. Additionally, no studies evaluated these international guidelines in the same population, nor compared them to the TNM system. Therefore, we investigated the prognostic value of six stratification systems employed by ten International guidelines, and the TNM system with respect to predicting disease specific survival (DSS).
 
 
 
 We retrospectively studied adult patients with DTC from a Dutch university hospital. Patients were classified using the risk classification described in the British, Dutch, French, Italian, Polish, Spanish, European Society of Medical Oncology, European Thyroid Association, and 2009 and 2015 American Thyroid Association (ATA) guidelines, and the latest TNM system. DSS was analyzed using the Kaplan-Meier method, and the statistical model performance using the C-index, AIC, BIC and PVE.
 
 
 
 We included 857 patients with DTC (79% PTC, 21% FTC). Median follow-up was 9 years, and 67 (7.8%) died due to DTC. The Dutch guideline had the worst statistical model performance, while the 2009 ATA/2014 British guideline had the best. However, the (adapted) TNM system outperformed all stratification systems.
 
 
 
 In a European population of patients with DTC, out of ten International guidelines employing six risk of recurrence stratification systems and one mortality based stratification system, our optimized age-adjusted TNM system (8th edition) outperformed all other systems.
