Assessing the influence of prostate tissue traits on Gallium-68 prostate-specific membrane-antigen positron-emission tomography/computed tomography: predictive factors for image positivity and locoregional recurrence in prostate cancer patients treated with radical prostatectomy and without prior or salvage treatment

Abstract

Background

Gallium-68 prostate-specific membrane-antigen positron emission tomography/computed tomography (⁶⁸Ga-PSMA-11 PET/CT) has recently emerged as a novel imaging modality, potentially improving oncologic outcomes for prostate cancer patients. This study aimed to assess the potential predictive factors associated with ⁶⁸Ga-PSMA-11 PET/CT positivity following persistent prostate-specific antigen (PSA) levels and primary biochemical recurrence post-radical prostatectomy (RP), focusing on prostate specimen characteristics. Furthermore, we aim to identify predictive factors for locoregional recurrence.

Methods

We conducted a retrospective analysis of 230 prostate cancer patients treated with RP and without prior salvage or adjuvant radiotherapy or systemic treatments. All patients underwent ⁶⁸Ga-PSMA-11 PET/CT scans to detect prostate cancer recurrence detection. Pathological findings were carefully examined and correlated with ⁶⁸Ga-PSMA-11 PET/CT positivity and locoregional recurrence.

Results

Our analysis showed that ⁶⁸Ga-PSMA-11 PET/CT positivity was associated with International Society of Urological Pathology (ISUP) grade group ≥3, presence of positive lymph node invasion at the time of RP, positive extra-prostatic extension, involvement of seminal vesicles and post-RP PSA levels ≥0.1 ng/ml. Additionally, we identified ISUP grade group 2 and ISUP grade group ≥3, whether with or without positive lymph node invasion, along with extra-prostatic extension, involvement of seminal vesicles and post-RP PSA ≥0.1 ng/ml were identified as factors associated with pelvic node recurrence.

Conclusion

Pathological findings emerge as robust predictors of ⁶⁸Ga-PSMA-11 PET/CT positivity and locoregional recurrences in cases of initial biochemical recurrence or persistence without prior adjuvant or salvage treatment. This diagnostic approach facilitates potential adjustments in management strategies, such as PSMA-guided radiotherapy or PSMA-guided lymphadenectomy.