Acute Toxicity and Quality of Life in a Post-Prostatectomy Ablative Radiation Therapy (POPART) Multicentric Trial

Abstract

Background: The aim of this study was to investigate the feasibility of ultrahypofractionated radiotherapy to the prostate bed in patients with biochemical and/or clinical relapse following radical prostatectomy who were enrolled in the prospective, observational, multicentric POPART trial (NCT04831970). Methods: Patients with post-radical prostatectomy PSA levels of ≥0.1–2.0 ng/mL and/or local relapse at PSMA PET/CT or multiparametric MRI were treated with Linac-based SBRT on the prostate bed up to a total dose of 32.5 Gy in five fractions every other day (EQD21.5 = 74.2 Gy). Maximum acute toxicity was assessed using the Common Terminology Criteria for Adverse Events version 5 scale. International Consultation on Incontinence Questionnaire—Short Form (ICIQ-SF) and Prostate Cancer Index Composite for Clinical Practice (EPIC-CP) scores were assessed at baseline and during the follow-up. Results: From April 2021 to June 2022, thirty men with a median age of 72 years (range 55–82) were enrolled in three centers. The median PSA level before RT was 0.30 ng/mL (range 0.18–1.89 ng/mL). At 3 months post-treatment, no GI or ≥2 GU side effects were reported; three patients (10%) experienced Grade 1 GU toxicity. No changes in ICIQ-SF or in the urinary domains of EPIC-CP were observed, while a transient worsening was registered in the bowel domain. At the same time point, all but two patients, who progressed distantly, were found to be biochemically controlled with a median post-treatment PSA level of 0.07 ng/mL (range 0–0.48 ng/mL). Conclusions: Our preliminary findings show that SBRT can be safely extended to the postoperative setting, without an increase in short-term toxicity or a significant decline in QoL. Long-term results are needed to confirm this strategy.

ESTRO ACROP consensus recommendation on the target volume definition for radiation therapy of macroscopic prostate cancer recurrences after radical prostatectomy

“…up to the level of cut end of vas deferens), unless of course there was initial seminal vesicle invasion [1] . This approach is similar to the recent multicentric, prospective, observational POPART trial, testing extreme hypofractionation in patients with biochemical and/or clinical relapse [30] . Even when a local relapse was visible on PSMA PET/CT or mpMRI (in 26% of patients), the entire prostate bed was (albeit stereotactically) irradiated.…”

Toxicity profile and Patient-Reported outcomes following salvage Stereotactic Ablative Radiation Therapy to the prostate Bed: The POPART multicentric prospective study

“…We recently demonstrated that highly focused radiation in a few fractions to the prostate bed can be safely delivered, with no significant acute ≥ G2 side effects nor deterioration in patient-reported QoL measures [15] . The present findings with an extended follow-up validate these initial data, thus adding further evidence that post-operative SBRT has favourable toxicity profiles in the short to medium term.…”

“…Eligibility criteria and treatment procedures have been previously reported in detail [15] . Briefly, patients enrolled in the trial should have had a biochemical relapse following RP (any type) with the prostate-specific antigen (PSA) not exceeding 2.0 ng/mL and no distant metastases on [18F]-PSMA positron emission tomography (PET) within 60 days prior to registration.…”

“…Accurate patient setup was obtained using kilovoltage cone-beam CT (CBCT) before each session to check the anatomical reproducibility. Dose–volume constraints were fully described elsewhere [15] .…”

“…Concerns have risen that too high doses to the anastomosis (where most recurrences occur) may lead to tissue injury, potentially resulting in an increased risk of severe toxicities. We have previously published the early findings of a prospective multicentric trial [15] evaluating the use of SBRT to the prostate bed in patients with biochemical relapse following RP and showed that it did not increase toxicity nor affect Quality of Life (QoL) in the short time. We herein report the updated results with longer follow-up, investigating possible predictors of toxicities and patient-reported outcomes.…”