Performance of Ga-68 PSMA PET/CT for diagnosis and grading of local prostate cancer

Background: We aimed to evaluate the utility of prostate-specific membrane antigen (PSMA) PET/CT for the detection of local disease within the prostate. Methods: This is a retrospective review of a single-center experience evaluating intraprostatic detection rates compared with final histopathology in a radical prostatectomy (RP) population. Seventy-two patients had PSMA PET/CT scan performed as part of their primary staging. Intraprostatic PSMA PET/CT avidity was assessed. PSMA PET/CT uptake was retrospectively correlated with patient characteristics including final histopathology, MRI Prostate Imaging Reporting and Data System (PI-RADS) score, clinical tumor stage, prostate-specific antigen (PSA) level, and patient age. Results: The sensitivity of PSMA PET/CT for the detection of RP-confirmed prostate cancer was 81.2%. Much higher sensitivity was found within certain subpopulations. The patient characteristics that most strongly correlated with focal intraprostatic PSMA PET/CT uptake were patient age (Kendall's tau coefficient tau(b) = 0.24, p < 0.05) and clinical T stage (tau(b) = 0.21, p < 0.05). The International Society of Urological Pathology (ISUP) grade group from final RP was predicted by standardized uptake value (SUVmax) and to a lesser extent PSA and the maximal dimension of PET-avid lesions. SUVmax monotonically increased with ISUP grade group. If SUVmax was above 10 g/mL, the final RP histopathology had a relative risk of 2.3 (95% CI 1.3-4.1) of being ISUP grade group 5. Conclusion: This trial provides early evidence that PSMA PET/CT assists in the grading of prostate cancer and suggests that the imaging modality is particularly accurate in subpopulations including the elderly and those with palpable disease. (C) 2021 Asian Pacific Prostate Society. Published services by Elsevier B.V.

Automated summary

The sensitivity of PSMA PET/CT for detecting RP-confirmed prostate cancer was 81.2%. Patient age and clinical T stage strongly correlated with focal intraprostatic PSMA PET/CT uptake. The ISUP grade group from final RP was predicted by SUVmax, PSA, and the maximal dimension of PET-avid lesions.