18F-DCFPyL PSMA-PET affects management of salvage radiotherapy for post-prostatectomy patients with biochemical failure

A matched cohort study

Authors

  • Andrew J. Arifin London Regional Cancer Program
  • Stephanie Gulstene London Regional Cancer Program
  • Andrew Warner London Regional Cancer Program
  • Glenn S. Bauman London Regional Cancer Program
  • Lucas C. Mendez London Regional Cancer Program

DOI:

https://doi.org/10.5489/cuaj.8165

Keywords:

biochemical failure, PSMA-PET, recurrent prostate cancer, salvage radiotherapy

Abstract

Introduction: Our objective was to assess the effect of 18F-DCFPyL prostate-specific membrane antigen (PSMA) positron emission tomography (PET) on the management and outcomes of patients receiving salvage radiotherapy following biochemical failure (BF) post-radical prostatectomy (RP) using a matched cohort analysis.

Methods: A PSMA-PET cohort of patients with BF post-RP was identified through a prospective registry. Patients from this registry were included if they did not have disease outside of the pelvis and underwent salvage radiotherapy to the prostate and/or pelvis. Case-control matching was performed with a contemporary cohort of patients with BF post-RP without PSMA-PET information.

Results: Forty-four patients were included in the PSMA-PET cohort and 80 were analyzed in the non-PSMA-PET cohort. The PSMA-PET cohort had a significantly higher pre-radiotherapy median prostate-specific antigen (PSA) of 0.48 ng/mL compared to 0.20 ng/mL in the non-PSMA-PET cohort (p<0.001) but these levels were similar after matching. The PSMA-PET cohort had a higher proportion of patients receiving radiotherapy to pelvic lymph nodes (n=27 [61.4%] vs. n=16 [20.0%], p<0.001). Median followup was 26 months (interquartile range 18.8–33) for both cohorts¬. BF-free survival and event-free survival were not significantly different between the two cohorts for all (p=0.662 and >0.99) and matched patients (p=0.808 and 0.808), respectively. Metastasis-free survival was significantly higher in the matched PSMA-PET cohort compared to the matched non-PSMA-PET cohort (p=0.046), although a higher proportion of patients in the non-PSMA-PET cohort underwent PSMA-PET restaging after BF (52 vs. 20%, p=0.08726).

Conclusions: Our study showed that patients undergoing PSMA-PET scans after BF post-RP had a higher likelihood of pelvic nodal treatment at the time of salvage RT. Despite higher PSA levels at salvage, we identified no recurrence or survival differences.

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Author Biographies

Andrew J. Arifin, London Regional Cancer Program

PGY-5 resident in radiation oncology at the London Regional Cancer Program.

Stephanie Gulstene, London Regional Cancer Program

PGY-4 resident in radiation oncology at the London Regional Cancer Program.

Andrew Warner, London Regional Cancer Program

Statistician at the London Regional Cancer Program.

Glenn S. Bauman, London Regional Cancer Program

Professor in the Division of Radiation Oncology at Western University.

Lucas C. Mendez, London Regional Cancer Program

Assistant professor in the Division of Radiation Oncology at Western University

Published

2023-05-30

How to Cite

Arifin, A. J., Gulstene, S., Warner, A., Bauman, G. S., & Mendez, L. C. (2023). 18F-DCFPyL PSMA-PET affects management of salvage radiotherapy for post-prostatectomy patients with biochemical failure: A matched cohort study. Canadian Urological Association Journal, 17(8), 247–53. https://doi.org/10.5489/cuaj.8165

Issue

Section

Original Research