Once-a-week or every-other-day urethra-sparing prostate cancer stereotactic body radiotherapy, a randomized phase II trial: 18 months follow-up results

Thomas Zilli*, Sandra Jorcano, Samuel Bral, Carmen Rubio, Anna M.E. Bruynzeel, Angelo Oliveira, Ufuk Abacioglu, Heikki Minn, Zvi Symon, Raymond Miralbell

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Background: To present the 18 months results from a prospective multicenter phase II randomized trial of short vs protracted urethra-sparing stereotactic body radiotherapy (SBRT) for localized prostate cancer (PCa). Methods: Between 2012 and 2015, a total of 170 PCa patients were randomized to 36.25 Gy in 5 fractions (6.5 Gy × 5 to the urethra) delivered either every other day (EOD, arm A, n = 84) or once a week (QW, arm B, n = 86). Genitourinary (GU) and gastrointestinal (GI) toxicity (CTCAE v4.0 scale), IPSS, and QoL scores were assessed at baseline, at the 5th fraction (5fx), 12th weeks (12W), and every 6 months after SBRT. The primary endpoint was biochemical control at 18 months and grade ≥ 3 toxicity (including grade ≥ 2 for urinary obstruction/retention) during the first 3 months. Results: Among the 165 patients analyzed, the toxicity stopping rule was never activated during the acute phase. Maximum acute grade 2 GU toxicity rates at 5fx were 17% and 19% for arms A and B, respectively, with only 2 cases of grade 2 GI toxicity at 5fx in arm A. At month 18, grade ≥ 2 GU and GI toxicity decreased below 5% and 2% for both arms. No changes in EORTC QLQ-PR25 scores for GU, GI, and sexual domains were observed in both arms between baseline and month 18. Four biochemical failures were observed, 2 in each arm, rejecting the null hypothesis of an unfavorable response rate ≤ 85% in favor of an acceptable ≥ 95% rate. Conclusions: At 18 months, urethra-sparing SBRT showed a low toxicity profile, with minimal impact on QoL and favorable biochemical control rates, regardless of overall treatment time (EOD vs QW).

Original languageEnglish
Number of pages10
JournalCancer Medicine
Volume9
Issue number9
DOIs
Publication statusPublished - 1 May 2020

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