SUO 2021: Impact of 18F-Fluciclovine PET/CT on Plans for ADT in Patients with Biochemical Recurrence of Prostate Cancer: Data Analysis from two Prospective Trials

(UroToday.com) The Society of Urologic Oncology (SUO) annual winter meeting included a prostate cancer session and a presentation by Dr. Gerald Andriole discussing the impact of 18F-fluciclovine PET/CT on plans for ADT in patients with biochemical recurrence of prostate cancer. Despite improvements in early detection and primary therapy, biochemical recurrence of prostate cancer after curative-intent primary therapy remains common. The advent of highly sensitive molecular imaging has allowed the identification of men with limited metastatic disease burden that might be more optimally treated with metastases-directed therapy rather than with systemic therapy. The LOCATE1 and FALCON2 trials assessed the impact of 18F-fluciclovine PET/CT on the management of patients with prostate cancer recurrence after curative-intent primary therapy. Thus, the objective of this study was to analyze data from LOCATE and FALCON to evaluate the impact of 18F-fluciclovine on plans for ADT in patients with biochemical recurrence of prostate cancer.

 

This study included a secondary analysis of LOCATE and FALCON data to characterize anatomical sites of disease recurrence and management decisions for patients with biochemical recurrence of prostate cancer who had an intended plan for treatment with ADT prior to undergoing 18F-fluciclovine PET/CT. Data from 317 patients who underwent 18F-fluciclovine PET/CT as part of these two trials were analyzed. All patients with a pre-scan plan for ADT either alone or in combination with another treatment modality were selected. PET/CT detection rates were determined at a per-patient level, for the prostate/prostate bed region, pelvic and extra-pelvic lymph nodes, soft tissues and bones. The patients’ treatment plans post-scan were compared with the pre-scan plans and were stratified according to imaging findings. The study flow chart is as follows:

 

Andriole_f18-0.jpg 

 

There were 146 patients that had a pre-scan plan for ADT (60 as monotherapy and 86 in combination with another modality), and PET/CT detected lesions in 85 (58%) of patients planned for ADT. Detection rates were as follows:

  • Prostate/bed: 30%
  • Pelvic lymph nodes: 25%
  • Extra-pelvic lymph nodes: 13%
  • Soft tissues: 2.1%
  • Bone: 13%

 

 Twenty-five (17%) patients had positivity confined to the prostate/bed, 21 (14%) had 18F-fluciclovine-positive pelvic nodes (± prostate/bed) but no other involvement and 39 (27%) had involvement outside the prostate/bed and pelvic nodes.  Post-scan, 93/146 (64%) patients had a change in management, 55 (59%) of which resulted in the patient no longer being prescribed ADT. Only 25% of the patients originally planned for ADT monotherapy still had a plan for ADT monotherapy post-scan. As follows is the Sankey plot illustrating pre- and post-scan management plans:

 

Andriole_f18-1.jpg 

 

Patients with a post-scan plan for ADT monotherapy had the greatest proportion of extra-pelvic involvement, and local disease was most common in those whose plan was altered to abort ADT.

 

Dr. Andriole concluded his presentation assessing the impact of 18F-fluciclovine PET/CT on plans for ADT in patients with biochemical recurrent prostate cancer with the following take-home messages:

  • Data from two prospective studies indicate that 18F-fluciclovine PET/CT influenced management plans for the majority of patients with a pre-scan plan that included ADT
  • Following 18F-fluciclovine PET/CT, ADT was aborted for approximately 2/5 of patients (55/146) of those intended for ADT
  • Management plans were commonly amended to target salvage therapy for lesions identified with 18F-fluciclovine PET/CT, and consequently likely spared patients the morbidity associated with ADT

Presented by: Gerald L. Andriole, Jr, MD, Royce Distinguished Professor, Chief of Urologic Surgery, Washington University, St. Louis, MO

Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Assistant Professor of Urology, Georgia Cancer Center, Augusta University/Medical College of Georgia, @zklaassen_md on Twitter during the 2021 Society of Urologic Oncology (SUO) Winter Annual Meeting, Orlando, FL, Wed, Dec 1 – Fri, Dec 3, 2021. 

References:

  1. Andriole GL, Kostakoglu L, Chau A, et al. The impact of positron emission tomography with 18F-Fluciclovine on the treatment of biochemical recurrence of prostate cancer: Results from the LOCATE Trial. J Urol 2019 Feb;201(2):322-331.
  2. Scarsbrook AF, Bottomley D, Teoh EJ, et al. Effect of 18F-Fluciclovine Positron Emission Tomography on the Management of Patients with Recurrence of Prostate Cancer: Results from the FALCON Trial. Int J Radiat Oncol Biol Phys. 2020 Jun 1;107(2):316-324.

 

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