Risk‐Stratified Surveillance for Recurrent Hepatocellular Carcinoma After Liver Transplantation: A Comparison With the RETREAT‐Guided Surveillance Protocol

BACKGROUND: Hepatocellular carcinoma (HCC) recurrence after liver transplantation (LT) is uncommon but associated with poor outcomes, requiring effective surveillance. We assessed adherence to and effectiveness of a risk-stratified surveillance protocol and compared it with the RETREAT-guided surveillance protocol. METHODS: We performed a single-center retrospective review of patients with HCC on explant after LT (2013-2023). Patients were assigned low- or high-risk surveillance based on explant pathology (AJCC tumor stage, grade, and vascular invasion). Protocol performance, modified surveillance strategies, and comparison with RETREAT across multiple cutoffs were assessed. RESULTS: Among 480 patients, 55 (11.5%) developed recurrence; 23 (41.8%) of these died, with median post-recurrence survival of 14 months. Only 15.8% were fully adherent, with higher adherence in low-risk patients (p<0.001). The protocol appropriately stratified risk (sensitivity 80.0%, specificity 54.1%) and retained substantially higher specificity than RETREAT even at RETREAT's conventional low-risk cutoff (32.0%) despite matching sensitivity; the two systems captured different patients (McNemar's test, p<0.001). Extrahepatic disease at recurrence was more common in high-risk patients (56.8% vs. 18.2%, p = 0.040). Fully adherent patients had earlier recurrence detection (206.4 vs. 666.9 days, p = 0.015). Modified protocols improved adherence but delayed some diagnoses; most low-risk recurrences occurred within 1 year and high-risk recurrences within 2 years. CONCLUSIONS: This protocol effectively stratifies recurrence risk and is more sensitive than the RETREAT-guided surveillance protocol. Modified strategies may improve adherence and reduce cost while maintaining effectiveness, particularly in low-risk patients.