Real‐world Israeli single institution experience with PET‐PSMA for staging of patients with clinically staged localized prostate carcinoma

Abstract

Background: A recent prospective trial, the proPSMA study, showed superior specificity and sensitivity of Positron emission tomography (PET) -Prostate-specific membrane antigen (PSMA) imaging compared standard Computerized tomography (CT) and bone scan for staging of recently diagnosed high-risk local prostate carcinoma for curative intent treatment. Aim: To share our experience with false-positive PET PSMA scans in newly diagnosed intermediate-risk prostate cancer. Methods and results: Here, we report a series of eight patients who underwent systemic staging using PET-PSMA with false-positive results who were ultimately treated with definitive radiation or surgery. Of the eight patients, two patients were diagnosed with favorable intermediate disease, four with unfavorable intermediate risk, and two with high-risk disease. Seven of eight were shown to have false-positive bone uptake, one patient had uptake in lung nodules. Three patients underwent bone biopsy and proven benign. The rest of the patients were proven as non-metastatic radiologically by repeat PSMA, CT, or Magnetic resonance imaging (MRI). All subsequently preceded to definitive localized treatment and remain disease free as of this study. Conclusion: This study emphasizes the importance of prudent clinical judgment when utilizing this highly sensitive imaging technique. K E Y W O R D S clinical observations, PET PSMA, prostate cancer 1 | INTRODUCTION Prostate cancer is the most common cancer in men worldwide and is second only to lung cancer in cancer mortality among men. 1According to the Surveillance, Epidemiology and End Results (SEER) database, 77% present with localized disease, 13% with regional lymph node involvement, and 6% with metastatic disease. 2 The current NCCN guidelines recommend bone scan as initial staging in all patients with high-risk disease defined as T3/T4 or PSA >20 or Gleason 8-10 and intermediate risk defined as T2b and T2c or Gleason 4 + 3 or PSA >10. 3 Similarly, American Society of Clinical Oncology (ASCO) guidelines recommend bone imaging for all high risk and unfavorable intermediate risk patients as previously defined. 4 PET PSMA has been shown to have higher sensitivity for detection of Yonaton Zarbiv and Yehudit Peerless contributed equally to this study.

New perspectives on metabolic imaging in the management of prostate cancer in 2022: A focus on radiolabeled PSMA‑PET/CT (Review)

“…The proPSMA study assessed the impact of 68GaPSMA PET/CT on the diagnosis and management of patients with localized high-risk prostate cancer (16). 68GaPSMA PET/CT clearly improves the accuracy of diagnosis and the staging of the disease, given that PSMA PET-CT showed a 27% (95% CI [23][24][25][26][27][28][29][30][31] increase in accuracy compared to conventional imaging [92% (88-95) vs. 65% (60-69); P<0.0001].…”

“…However, caution must be taken given the lack of available data concerning a potential improvement in patient outcomes and the risk of false positives (23,24). 68Ga-PSMA: a prognostic factor?…”