Differentiated thyroid cancer in two European referral centres: impact of different diagnostic and therapeutic strategies

Objective To evaluate differences in the presentation, diagnostic/therapeutic approaches, and outcome of differentiated thyroid cancer (DTC) in an Italian and a Dutch referral centre. Methods We retrospectively included 919 patients (586 Italian, 333 Dutch), and compared the two cohorts as a whole and according to ATA risk classes. Dynamic risk stratification (DRS) and Kaplan–Meier curves were used to compare progression-free survival (PFS) and disease-specific survival (DSS). Results Several differences (P < 0.001) were found in clinicopathological features and in diagnostic/therapeutic modalities. The Dutch cohort had a higher age at diagnosis, a higher number of patients presenting with metastatic disease, and patients with stage III/IV. Most Italian patients showed a low/intermediate ATA risk, while high-risk patients represented half of the Dutch cohort. The Dutch cohort received a more intensive first treatment and more additional treatments during follow-up (i.e. surgery, radiotherapy, and systemic treatments). DRS analysis showed comparable excellent and biochemical incomplete responses, while the Dutch cohort had a lower rate of indeterminate and a higher rate of structural incomplete responses (P < 0.001). The Dutch cohort had a significantly worse 5-year PFS, and TC-related mortality was 10 and 1% for the Dutch and Italian cohorts, respectively, in line with the higher rate of advanced disease at presentation, with DSS still excellent for both. Conclusion Data reported in the present comparison between two European countries highlight a different prevalence, presentation, and outcome of DTC, likely due to variabilities in healthcare systems, iodine nutritional status, and diagnostic and treatment approaches.