A1 Refereed original research article in a scientific journal
Every-Other-Day Versus Once-a-Week Urethra-Sparing Prostate Stereotactic Body Radiation Therapy: 5-Year Results of a Randomized Phase 2 Trial
Authors: Zilli Thomas, Jorcano Sandra, Bral Samuel, Symon Zvi, Rubio Carmen, Bruynzeel Anna ME, Ibrahimov Roman, Minn Heikki, Oliveira Angelo, Bertaut Aurélie, Constantin Guillaume, Miralbell Raymond
Publisher: Elsevier
Publication year: 2023
Journal: International Journal of Radiation Oncology - Biology - Physics
Journal name in source: International journal of radiation oncology, biology, physics
Journal acronym: Int J Radiat Oncol Biol Phys
ISSN: 0360-3016
eISSN: 1879-355X
DOI: https://doi.org/10.1016/j.ijrobp.2023.03.057
Web address : https://doi.org/10.1016/j.ijrobp.2023.03.057
Purpose
The objective of this study was to present the 5-year results from a prospective, multicenter, phase 2 randomized trial of every-other-day (EOD) versus once-a-week (QW) urethra-sparing stereotactic body radiation therapy for localized prostate cancer.
Methods and Materials
Between 2012 and 2015, 170 patients with cT1c-3aN0M0 prostate cancer from 9 European institutions were randomized to 36.25 Gy in 5 fractions (6.5 Gy/fraction to the urethra) delivered either EOD (arm A, n = 84) or QW (arm B, n = 86). The median follow-up was 78 months (interquartile range, 66-89 months) and 77 months (interquartile range, 66-82 months) for arms A and B, respectively.
Results
Among the 165 patients treated and retained for the final analysis (arm A, n = 82; arm B, n = 83), acute toxicity (National Cancer Institute Common Terminology Criteria for Adverse Events version 4.03 scale) was mild or absent, with no differences between arms. The 5-year grade 2 or greater genitourinary toxicity-free survival was 75.9% and 76.1% for arms A and B, respectively (P = .945), whereas the 5-year grade 2 or greater gastrointestinal toxicity-free survival was 89% and 92% for arms A and B, respectively (P = .596). No changes in European Organisation for Research and Treatment of Cancer QLQ-PR25 scores were observed in both arms for genitourinary, gastrointestinal, and sexual domains at 5-year follow-up compared with baseline. At the last follow-up, biochemical failure was observed in 14 patients in the EOD arm and in 7 patients in the QW arm, with a 5-year biochemical relapse-free survival rate of 92.2% and 93% for arms A and B, respectively (P = .13).
Conclusions
Stereotactic body radiation therapy for prostate cancer with a 10% dose reduction to urethra was associated with a minimal effect on urinary function and quality of life regardless of an EOD or QW fractionation schedule. Biochemical control so far has been encouraging and much alike in both study arms, although longer follow-up is probably needed to assess the true value of overall treatment time on disease outcome.
