68Ga-PSMA-11 PET/CT Improves Tumor Detection and Impacts Management in Patients with Hepatocellular Carcinoma

Abstract

Hepatocellular carcinoma (HCC) is the sixth most prevalent cancer and the third most frequent cause of cancer-related death. A growing number of local and systemic therapies are available, and accurate staging is critical for management decisions. We assessed the impact of neovasculature imaging by ⁶⁸Ga-PSMA-11 PET/CT on disease staging, prognostic groups, and management of patients with HCC compared with staging with CT. Methods: Forty patients who received imaging with ⁶⁸Ga-PSMA-11 PET/CT for HCC staging between September 2018 and September 2019 were retrospectively included. Management before and after PET scanning was assessed by standardized surveys. The presence of HCC was evaluated by 3 masked readers on a per-patient and per-region basis for PET/CT (PET criteria) and multiphase contrast-enhanced CT (CT criteria) in separate sessions. Lesions were validated by follow-up imaging or histopathology, and progression-free survival was recorded. Endpoints were detection rate and positive predictive value for ⁶⁸Ga-PSMA-11 PET versus CT, interreader reproducibility, and changes in stage, prognostic groups, and management plans. Results: Median age was 65 y (range, 37-81 y), and median Child-Pugh score was 5 (range, 5-9). Most patients were treatment-naïve (27/40, 67.5%). The sensitivity of PET versus CT to identify liver lesions for patients with lesion validation was 31 of 32 (97%) for both modalities, whereas it was 6 of 6 (100%) versus 4 of 6 (67%), respectively, for extrahepatic lesions. PET and CT each had a positive predictive value of 100% at the liver level. PET versus CT stage was congruent in 30 of 40 (75%) patients; upstaging was seen in 8 of 40 patients (20%), whereas 2 of 40 (5%) had downstaging by PET. Intended management changed in 19 of 40 patients (47.5%); 9 of 19 of these patients were found to have detectable distant metastases (47.4%) and assigned stage 4 disease, most of whom were shifted to systemic therapy (8/9, 89%). Two patients underwent ¹⁷⁷Lu-PSMA-617 radioligand therapy. Median progression-free survival was 5.2 mo for the entire cohort; 5.3 mo for PET M0, and 4.7 mo for PET M1 patients, respectively. Conclusion:⁶⁸Ga-PSMA-11 PET demonstrated higher accuracy than CT in the detection of HCC metastases and was associated with a management change in about half the patient cohort.

Keywords: PET; PSMA; hepatocellular carcinoma; staging; theranostic.