Prospective Evaluation of Follow-Up De-Escalation to Primary Care in Differentiated Thyroid Cancer with Excellent Response to Therapy

Background: Dynamic risk stratification (DRS) enables response-adapted follow-up in differentiated thyroid carcinoma (DTC). However, prospective data supporting surveillance de-escalation and discharge to primary care (PC) after an excellent response (ER) is lacking. Methods: We conducted a longitudinal cohort study with a prospectively conducted postdischarge reassessment, including 154 patients with DTC treated with total thyroidectomy, with or without radioiodine ablation, who completed ≥5 years of specialist follow-up and were discharged to PC after achieving ER. A small subset ( n = 9) of clinically stable patients was also discharged despite a persistent indeterminate response (IR), based on clinical judgment. Patients underwent a standardized reassessment ≥5 years after discharge to PC. DRS was assessed at three predefined time points 6 months after initial therapy, final predischarge specialist visit, and postdischarge reassessment. Outcomes included recurrence, additional interventions, real-world PC follow-up practices, referrals back to specialist care, and patient-reported outcomes collected at reassessment using a study-specific 5-point Likert-type questionnaire. Results: Baseline American Thyroid Association-2025 recurrence risk was low 78/154 (50.6%), intermediate-low 44/154 (28.6%), intermediate-high 23/154 (14.9%), and high 9/154 (5.8%). ER increased from 118/154 (76.6%) at 6 months to 145/154 (94.2%) at predischarge and to 148/154 (96.1%) at postdischarge reassessment ( p < 0.001). At last predischarge visit, 9/154 (5.8%) had an IR, decreasing to 6/154 (3.9%) at postdischarge reassessment. No biochemical or structural recurrences were observed over a mean postdischarge follow-up of 70.3 ± 10.6 months. All non-ER findings at reassessment occurred exclusively in patients already classified as IR at discharge, with no deterioration from ER. During specialist follow-up, 8/154 (5.2%) required additional interventions. PC surveillance was characterized by low-intensity follow-up, with thyroglobulin testing in 11/154 (7.1%), no routine neck ultrasound, and stable levothyroxine dosing. Premature re-referral to specialist care occurred in 13/154 (8.4%) without evidence of recurrence. Despite favorable outcomes, 66/154 (42.9%) reported high fear of recurrence and 141/154 (91.6%) preferred specialist follow-up. Conclusions: Our findings suggest that patients with DTC who complete ≥5 years of specialist follow-up and achieve ER may be safely transitioned to PC. ER represents a stable clinical state, with minimal risk of clinically meaningful recurrence even with markedly reduced biochemical and imaging surveillance. These findings support a response-adapted long-term care model centered in PC, focused on thyroid hormone replacement and TSH monitoring. Further studies are warranted to confirm these findings.