Welcome to PracticeUpdate! We hope you are enjoying access to a selection of our top-read and most recent articles. Please register today for a free account and gain full access to all of our expert-selected content.
Already Have An Account? Log in Now
Safety and Efficacy of Virtual Prostatectomy With Single-Dose Radiotherapy in Patients With Intermediate-Risk Prostate Cancer
abstract
This abstract is available on the publisher's site.
Access this abstract nowImportance
Ultra-high single-dose radiotherapy (SDRT) represents a potential alternative to curative extreme hypofractionated stereotactic body radiotherapy (SBRT) in organ-confined prostate cancer.
Objective
To compare toxic effect profiles, prostate-specific antigen (PSA) responses, and quality-of-life end points of SDRT vs extreme hypofractionated SBRT.
Design, Setting, and Participants
The PROSINT single-institution phase 2 randomized clinical trial accrued, between September 2015 and January 2017, 30 participants with intermediate-risk prostate cancer to receive SDRT or extreme hypofractionated SBRT. Androgen deprivation therapy was not permitted. Data were analyzed from March to May 2020.
Interventions
Patients were randomized in a 1:1 ratio to receive 5 × 9 Gy SBRT (control arm) or 24 Gy SDRT (test arm).
Main Outcomes and Measures
The primary end point was toxic effects; the secondary end points were PSA response, PSA relapse-free survival, and patient-reported quality of life measured with the International Prostate Symptom Score (IPSS) and Expanded Prostate Cancer Index Composite (EPIC)-26 questionnaires.
Results
A total of 30 men were randomized; median (interquartile range) age was 66.3 (61.2-69.9) and 73.6 (64.7-75.9) years for the SBRT and SDRT arms, respectively. Time to appearance and duration of acute and late toxic effects were similar in the 2 trial arms. Cumulative late actuarial urinary toxic effects did not differ for grade 1 (hazard ratio [HR], 0.41; 90% CI, 0.13-1.27) and grade 2 or greater (HR, 1.07; 90% CI, 0.21-5.57). Actuarial grade 1 late gastrointestinal (GI) toxic effects were comparable (HR, 0.37; 90% CI, 0.07-1.94) and there were no grade 2 or greater late GI toxic effects. Declines in PSA level to less than 0.5 ng/mL occurred by 36 months in both study arms. No PSA relapses occurred in favorable intermediate-risk disease, while in the unfavorable category, the actuarial 4-year PSA relapse-free survival values were 75.0% vs 64.0% (HR, 0.76; 90% CI, 0.17-3.31) for SBRT vs SDRT, respectively. The EPIC-26 median summary scores for the genitourinary and GI domains dropped transiently at 1 month and returned to pretreatment scores by 3 months in both arms. The IPSS-derived transient late urinary flare symptoms occurred at 9 to 18 months in 20% (90% CI, 3%-37%) of patients receiving SDRT.
Conclusions and Relevance
In this randomized clinical trial among patients with intermediate-risk prostate cancer, SDRT was safe and associated with low toxicity, and the tumor control and quality-of-life end points closely match the SBRT arm outcomes. Further studies are encouraged to explore indications for SDRT in the cure of prostate cancer.
Additional Info
Disclosure statements are available on the authors' profiles:
Safety and Efficacy of Virtual Prostatectomy With Single-Dose Radiotherapy in Patients With Intermediate-Risk Prostate Cancer: Results From the PROSINT Phase 2 Randomized Clinical Trial
JAMA Oncol 2021 Mar 11;[EPub Ahead of Print], C Greco, O Pares, N Pimentel, V Louro, I Santiago, S Vieira, J Stroom, D Mateus, A Soares, J Marques, E Freitas, G Coelho, M Seixas, A Lopez-Beltran, Z FuksFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
Advanced Prostate Cancer Center of Excellence
Visit our Advanced Prostate Cancer Center of Excellence for additional, in-depth coverage.
Advanced Prostate Cancer
Radiotherapy for intermediate-risk prostate cancer has typically been delivered over many treatment fractionations, with typical regimens in the United States consisting of treatment over 35 different fractionations. More recently, there has been a movement towards shorter fractionation schemes that have essentially equivalent outcomes. However, in this particular study, there is a comparison between single-dose radiotherapy and extreme hypofractionated stereotactic body radiotherapy (SBRT). In this small, single-institution, phase II randomized trial, a total of 30 participants were randomized, and half of them were given only a single dose of radiation. No PSA relapses occurred in the men with favorable intermittent-risk disease, and the actuarial 4-year PSA relapse rates were essentially equivalent within the unfavorable intermediate-risk disease category.
The patients who received the single-dose therapy had transient decreases in genitourinary and GI patient-reported outcomes; however, these had returned to pretreatment levels by 3 months. Of those who had a single dose, late urinary symptoms occurred in about 20%; but, overall, single-dose therapy has the potential to be a cost-effective and patient-friendly treatment, and, clearly, additional studies with a larger number of patients are required in order to gain a better understanding of this novel treatment approach.