ETA2024 Poster Presentations Clinical thyroid cancer research-2 (10 abstracts)
1Istituto Auxologico Italiano, Universita Degli Studi di Milano, Endocrinology, Milano, Italy; 2Clínica Universidad de Navarra; 3Istituto Auxologico Italiano
Purpose: The generally good prognosis of low- and intermediate-risk differentiated thyroid cancer (DTC) underscored the need to identify those few patients who relapse.
Methods: Records of 299 low- or intermediate-risk DTC patients (mean follow-up 8.2 ± 6.2 years) were retrospectively reviewed. The sample was classified following the American Thyroid Association (ATA) Dynamic Risk Stratification (DRS) system.
Results: After classifying patients according to DRS at the first visit following initial therapy (FU1), structural recurrence occurred in 2/181 (1.1%), 5/81 (6.2%) and 13/26 (50.0%) with excellent, intermediate, and biochemical incomplete response to treatment, respectively. All relapses but one happened within 5 years from FU1. Univariate analysis comparing excellent, indeterminate and biochemical incomplete with structural incomplete responses at the end of the follow-up (FUe), identified tumour size (P <0.001), T status (<0.001), positive lymph nodes (N) (P <0.01), multifocality (P <0.004), need of additional radioiodine (RAI) (P <0.0001), and first DRS status (P <0.0003) as risk factors of recurrence. In the multivariate analysis, only RAI remained statistically significant (P <0.02). Comparison between excellent and indeterminate with biochemical and structural incomplete responses, identified tumour size (P <0.0004), T (P <0.01), N (P <0.0001), bilaterality (P <0.03), first DRS status (P <0.0001), and RAI (P <0.001) as recurrence risk factors. T (P <0.01) and first DRS (P <0.0006) were confirmed in the multivariate analysis.
Conclusions: Patients with DTC classified as low- or intermediate-risk of recurrence with excellent response to treatment at FU1 rarely develop structural disease and this occurs almost exclusively in the first 5 years. Initial DRS status is an accurate tool for determining the risk of recurrence.