EAU 2021: Predicting Early Biochemical Progression in Prostate Cancer Patients Staged with PSMA PET and Multiparametric Magnetic Resonance Imaging

(UroToday.com) In the Prostate Cancer Detection by MR, PET, and Micro-US Imaging session at the 2021 European Association of Urology annual meeting, Dennie Meijer presented a discussion of a study in which the authors aimed to identify predictors of biochemical recurrence (BCR) in patients who opt for robot-assisted laparoscopic radical prostatectomy (RARP) for localized prostate cancer (PCa); they took into account conventional prognostic variables, as well as multiparametric magnetic resonance imaging (mpMRI) and prostate-specific membrane antigen (PSMA) positron emission tomography (PET) imaging.

This was an observational study that included 500 patients who underwent RARP and extended pelvic lymph node dissection (ePLND). Outcome measurement was biochemical progression of disease, defined as any post-operative PSA ≥0.2 ng/mL. A Cox-regression analysis was performed to assess predictors for biochemical progression, including initial prostate-specific antigen (PSA)-value, biopsy Grade Group (GG), T-stage on mpMRI, and lymph node status on PSMA PET imaging (miN0 vs. miN1).

The median total follow-up of all included patients was 12.8 months (IQR 6.6-22.3). Full demographics are seen below:

Meijer_EAU21_Figure1.png

When assessing BCR after surgery, initial PSA-value (per doubling; OR 1.24 (95%CI 1.08-1.43), p=0.003), biopsy GG ≥4 vs. GG 1-2 (OR 2.33 (95%CI 1.47-3.69), p<0.001), T-stage on mpMRI (rT3a vs. rT2: OR 2.04 (95%CI 1.30-3.20), p=0.002; ≥rT3b vs. rT2: OR 4.87 (95%CI 3.24-7.32), p<0.001) and miN1 on PSMA PET imaging (OR 2.16 (95%CI 1.46-3.20), p<0.001) were independent predictors of biochemical progression of disease.

Moreover, the number of pelvic lymph node metastases on PSMA PET was significantly associated with biochemical progression: One pelvic lymph node metastasis vs. no metastatic disease resulted in an OR 2.60 (95%CI 1.57-4.31), p<0.001; two pelvic lymph node metastases or more on PSMA PET vs. no metastatic disease resulted in an OR 4.61 (95%CI 2.84-7.48), p<0.001. This is seen on the KM curve below:

Meijer_EAU21_figure2.png

Beyond traditional clinic predictors (Initial PSA-value, biopsy GG ≥4), they found that imaging factors (≥rT3 disease on mpMRI and miN1 disease on PSMA PET) were predictors for early biochemical progression after RARP. Furthermore, the number of pelvic lymph node metastases on staging PSMA PET was associated with biochemical progression.

The MV analysis is below:

Meijer_EAU21_figure3.png

They concluded that identifying patients with an increased risk of biochemical progression after surgery may have implications for patient counseling in radical treatment decisions and on patient selection for modern (neo-)adjuvant and systematic treatments.

Presented by: Dennie Meijer, MD, Research Associate, Amsterdam UMC, Amsterdam

Written by: Thenappan (Thenu) Chandrasekar, MD – Urologic Oncologist, Assistant Professor of Urology, Sidney Kimmel Cancer Center, Thomas Jefferson University, @tchandra_uromd on Twitter during the 2021 European Association of Urology, EAU 2021- Virtual Meeting, July 8-12, 2021.

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