Affiliation:
1. Department of Radiation Oncology Mid‐North Coast Cancer Institute Coffs Harbour New South Wales Australia
2. Department of Radiation Oncology North Coast Cancer Institute, Lismore Base Hospital Lismore New South Wales Australia
Abstract
AbstractIntroductionThe Australian Faculty of Radiation Oncology Genitourinary Group (FROGG) developed prostate bed clinical target volume (CTV) contouring guidelines which were subsequently used to develop the National EviQ guidelines for adjuvant and salvage post‐prostatectomy radiotherapy (PPRT). These guidelines were based mainly upon consensus agreement. With the advent of prostate‐specific membrane antigen (PSMA) positron emission tomography (PET), sites of recurrence can now be detected with low prostate‐specific antigen (PSA) levels following radical prostatectomy. We evaluated sites of recurrence in patients treated with FROGG/EviQ CTVs to inform upcoming modifications of these guidelines.MethodsAt our institution, we use the FROGG/EviQ guidelines for PPRT. From 2015, patients with PSA failure following PPRT have been re‐staged using PSMA PET imaging. We identified patients with PET‐avid local, nodal, and distant recurrences, fusing them with original treatment plans to determine whether recurrences were within or outside the prostate bed CTV. Regional nodal failures were reviewed to determine if they were within current elective node contouring guidelines.ResultsNinety‐four patients had positive PSMA PET following PPRT. Nine (9.6%) recurrences were local, seven being local‐only. One local recurrence (1.1%) was just superior to the contoured prostate bed CTV, located within the vas deferens. Seventy‐three (77.7%) patients had a component of node failure, with 56 (59.6%) having node‐only failure. Sites of nodal relapses were covered by standard contouring guidelines 60.3% of the time.ConclusionThe low recurrence rate outside of current prostate bed CTV contouring guidelines is consistent with other studies using contemporary contouring, and validates the efficacy of the current FROGG/EviQ prostate bed CTV definition.
Subject
Radiology, Nuclear Medicine and imaging,Oncology
Reference27 articles.
1. Post-prostatectomy radiation therapy: Consensus guidelines of the Australian and New Zealand Radiation Oncology Genito-Urinary Group
2. EviQ: Cancer Institute NSW.Prostate adenocarcinoma adjuvant EBRT post radical prostatectomy.2022. [Cited 12 Nov 2022.] Available from URL:https://www.eviq.org.au/radiation‐oncology/urogenital/prostate/304‐prostate‐adenocarcinoma‐adjuvant‐ebrt‐post‐rad.
3. EviQ: Cancer Institute NSW.Prostate adenocarcinoma salvage EBRT post radical prostatectomy.2022. [Cited 12 Nov 2022.] Available from URL:https://www.eviq.org.au/radiation‐oncology/urogenital/prostate/305‐prostate‐adenocarcinoma‐salvage‐ebrt‐post‐radi.
4. Mapping of Local Recurrences After Radical Prostatectomy Using 68-Gallium–Prostate-Specific Membrane Antigen Positron Emission Tomography/Computed Tomography: Implications for Postprostatectomy Radiation Therapy Clinical Target Volumes
5. Target definition in salvage postoperative radiotherapy for prostate cancer: 18F-fluorocholine PET/CT assessment of local recurrence