Differentiated thyroid cancer: disease status 1 year after primary treatment and prognostic tools. Longitudinal data of the Italian Thyroid Cancer Observatory.

  • Background. Management of differentiated thyroid cancer (DTC) is driven by the likelihood of persistent/recurrent disease. Current practice guidelines are based on risk estimates obtained in studies of small cohorts or retrospective series. To assess their accuracy, we analyzed rates of structural disease 6-18 months after primary treatment in a large prospective cohort of DTC patients.

    Methods. We analyzed data from the Italian Thyroid Cancer Observatory’s observational database, which prospectively enrolls newly diagnosed DTC in 45 Italian centers. Patients with 6-18 months of follow-up were included in the study.  Risk of persistent/recurrent disease and treatment responses were classified according to 2015 American Thyroid Association (ATA) guidelines.

    Results. 2730 patients (74% females, median age: 49 years) were enrolled. Primary surgery was total thyroidectomy in 2619 (95.9%) cases; neck dissection was performed in 1096 (40%). Most of the DTCs were papillary (2532, 92.7%). Radioiodine remnant ablation was perfomed in  1793 (65.7%) cases. Persistent/recurrent disease risk was low in 1386 (50.8%), intermediate in 1168 (42.8%), and high in 176 (6.4%). Responses to primary treatment recorded at 6-18 months were: excellent in 1675 (61.4%), biochemical incomplete in 63 (2.3%), indeterminate in 922 (33.8%), and structural incomplete in 70 (2.6%). High and intermediate risk statuses were associated with higher rates of structural disease at 6-18 months (17% and 2.7%, respectively, vs. 0.6% for low risk; odds ratios [95% confidence intervals]: 35.22 [15.41 – 90.66] and 4.85 [2.18 – 12.23], respectively; p <0.0001).

    Conclusion. The 2015 ATA risk stratification system is an effective predictor of persistent/recurrent DTC. 

 

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