ASCO 2022: Cohort Study of Patients With Oligorecurrent Prostate Cancer: Oncological Outcomes of Patients Treated With Salvage Lymph Node Dissection via PSMA Radioguided Surgery

( At the 2022 American Society of Clinical Oncology Annual Meeting held in Chicago and virtually, the poster session focused on Prostate, Testicular, and Penile cancers on Monday afternoon included a presentation from Dr. Sophie Knipper discussing prostate-specific membrane antigen (PSMA)-guided radiosurgery for oligorecurrent prostate cancer.

The increasing utilization of prostate-specific membrane antigen (PSMA) positron-emission tomography (PET) for patients with biochemically recurrent disease following local therapy has allowed the detection of small and/or atypically localized metastatic prostate cancer lesions. The question of the best management of these patients is somewhat unclear. One approach that has been taken in a subset of patients with recurrent oligometastatic prostate cancer is salvage surgery, including with PSMA-targeted radioguidance (PSMA-RGS). Dr. Knipper and colleagues sought to assess the oncological outcomes of this approach in men with oligo-recurrent prostate cancer and to identify predictive preoperative factors of improved outcomes.

To do so, they performed a cohort study of patients treated at two tertiary care centers. To be eligible for inclusion, patients had biochemical recurrence (BCR) following radical prostatectomy (RP) and underwent imaging with PSMA PET prior to receiving salvage PSMA-RGS between 2014 and 2020. They used Kaplan-Meier and multivariable Cox regression models adjusted for various parameters to test for BCR-free survival (BFS) and therapy-free survival (TFS) differences and classified postoperative complications according to the Clavien-Dindo schema.

They identified 364 patients who were treated with PSMA-guided surgery for oligo-recurrent prostate cancer. At the time of surgery, patients’ had a median (IQR) age of 67 (61-71) years and the median preoperative PSA was 1.0 (0.5-1.9) ng/ml.

Metastatic soft-tissue prostate cancer metastases could be removed in 343 (94.2%) patients. Within three months following surgery, 24 (6.6%) patients suffered from Clavien-Dindo complications ranging from grade III-IV.

During follow-up, 225 patients experienced BCR and 121 patients received further therapy. Median follow-up for patients who did not experience BCR and who did not receive further therapy were 10.8 months and 10.3 months, respectively.

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Median (IQR) BFS and TFS were 7.8 (5.4-10.5) and 35.5 months (25.9-45.9 months).

At two years of follow-up, the BFS rate was 31.9% and TFS rate was 58.0%.

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Based on multivariable analyses, the authors identified that patients with higher preoperative PSA (HR: 1.1), higher number of PSMA-avid lesions on preoperative imaging (HR: 1.2) and multiple (pelvic plus retroperitoneal) localizations (HR: 1.9), as well as retroperitoneal localization (HR: 2.0) of lesions in PSMA PET imaging were independently more likely to have BCR after PSMA-RGS.

The authors therefore conclude that salvage surgery in oligo-recurrent prostate cancer should be considered an experimental treatment approach, requiring careful patient selection. Further studies are needed to better define the oncological value of salvage surgical procedures in oligo-recurrent prostate cancer.

Presented by: Sophie Knipper, MD, Martini-Klinik Prostate Cancer Center, Hamburg, Germany

Written by: Christopher J.D. Wallis, University of Toronto, Twitter: @WallisCJD during the 2022 American Society of Clinical Oncology (ASCO) Annual Meeting, Chicago, IL, Fri, June 3 – Mon, June 7, 2022.