AUA 2024: Predicting Positive 68Ga-PSMA PET/CT Scans in Biochemical Recurrence Following Prostatectomy.

( The 2024 American Urological Association (AUA) annual meeting held in San Antonio, TX between May 3 and May 6, 2024, was host to the prostate cancer podium staging session. Dr. Maya Ataya presented the results of a retrospective study using a cohort of prostate cancer patients who underwent PSMA-PET scans for biochemical recurrence (BCR) after radical prostatectomy (RP).

Dr. Ataya began by emphasizing why 68Ga-PSMA-PET has emerged as the new imaging modality increasingly utilized in biochemical recurrence (BCR) after treatment with curative intent for prostate cancer. This is primarily due to its enhanced capability to detect sites of disease recurrence, surpassing conventional imaging methods in detection rates. The primary objective of this study was to explore the clinical and pathological factors associated with positive PSMA-PET scans in patients experiencing BCR following radical prostatectomy (RP).

They queried for patients with BCR prostate cancer (PCa) from 2017 to 2022 which correlates when Indiana University held expanded access indication for the clinical use of 68Ga-PSMA-PET. They identified 815 patients who had undergone PSMA-PET scans as part of their assessment for BCR with no previous evidence of distant metastasis on conventional imaging. Of these 542 had BCR post-RP, and of the latter, 339 (63%) were found to have a positive PSMA-PET, and 203 (37%) had a negative PSMA-PET.
Patient characteristics are shown in the table 2 below. Briefly, patients with a positive PSMA-PET had significantly higher median PSA, and more patients had a PSA value ≥0.2.PSMA-PET had significantly higher median PSA and more patients had a PSA value ≥0.2
In univariate analysis, a PSA value ≥0.2, ISUP grade ≥3, and < 6 months since treatment were found to be significantly associated with a positive PSMA-PET scan. These associations remained significant in the multivariate logistical regression analysis, with a PSA value ≥0.2 (OR 4.75; 95% CI 2.37-9.51, p < 0.001) and ISUP grade ≥3 (OR 2.13; 95% CI 1.30-3.48, p = 0.002). However, time since treatment with PSMA-PET was not a significant predictor of a positive PET scan.univariate analysis
Dr Ataya wrapped up her presentation concluding that among patients with BCR following radical prostatectomy, the predictors of a positive scan are:

  • PSA value ≥0.2
  • ISUP grade ≥ 3

Presented by: Maya Ataya, MD, Postdoctoral Researcher, Indiana University. Indiana University  

Written by: Julian Chavarriaga, MD - Society of Urologic Oncology (SUO) Clinical Fellow at The University of Toronto, @chavarriagaj on Twitter during the 2024 American Urological Association (AUA) annual meeting held in San Antonio, TX between May 3rd and May 6th, 2024