Consideration of Early Dynamic Risk Stratification to Guide Discharge from Oncologic Follow-up in Patients with Differentiated Thyroid Cancer.

BACKGROUND The current dogma is a life-long follow-up for patients treated for follicular-derived differentiated thyroid cancers (DTC). Our primary objective was to determine the time to recurrence in a series of DTC patients with an excellent response to therapy 6 months after total thyroidectomy and radioiodine therapy. The secondary objectives were to determine the time to suspicion of recurrence and to identify factors associated with recurrence. METHODS This retrospective cohort study included patients treated for DTC between 2008 and 2012 and in remission 6 months after total thyroidectomy and radioiodine treatment. The criteria for remission were negative imaging and suppressed thyroglobulin (Tg) < 0.2 ng/mL or rh-TSH-(recombinant human TSH) stimulated Tg < 1 ng/mL according to the 2015 ATA (American Thyroid Association) guidelines. Recurrence was defined by cytologically and/or histologically proven cervical lymph node metastasis or the administration of a second radioiodine treatment. RESULTS Among 721 patients treated for DTC, 158 were excluded because of persistent disease at 6 months and 71 because of missing follow-up data and 492 were included. The mean and median follow-up time were 7.0 and 7.9 years [IQR 2.1-11.3]. Recurrence occurred for 7 patients (1.4%), 1 initially classified as high recurrence risk, 3 as intermediate and 3 as low risk according to the 2015 ATA guidelines. All relapses occurred within 10 years after initial management (4 within the first 5 years). For patients with recurrence, rise in Tg and/or suspicious lymph node were detected in 6 out of 7 cases in the first 8 years, and for the last case 10 years after initial surgery. CONCLUSION Low and intermediate recurrence risk DTC patients with excellent response 6 months after total thyroidectomy and radioiodine and in remission 10 years later have an extremely low recurrence risk. Follow-up might be undertaken by primary care providers from this time point. These discharge recommendations should be confirmed by further prospective studies.