Stereotactic Body Radiation Therapy Boost for Intermediate-Risk Prostate Cancer: A Phase 1 Dose-Escalation Study

Yasir Alayed, Andrew Loblaw, William Chu, Motasem Al-Hanaqta, Andrew Chiang, Suneil Jain, Hans Chung, Danny Vesprini, Gerard Morton, Ananth Ravi, Melanie Davidson, Andrea Deabreu, Alexandre Mamedov, Liying Zhang, Darby Erler, Patrick Cheung*

*Corresponding author for this work

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Purpose: High-dose-rate brachytherapy boost plus external beam radiation therapy is an established option for intermediate-risk prostate cancer (PCa). Stereotactic body radiation therapy (SBRT) boost can potentially mimic high-dose-rate boost and could be a viable alternative. Here we report the long-term outcomes of a phase 1 dose-escalation trial of single-fraction SBRT boost. Methods and Materials: Patients had intermediate-risk PCa and were accrued to 3 different SBRT single-fraction dose-level cohorts (10 Gy, 12.5 Gy, and 15 Gy). All received supplemental radiation therapy afterwards (37.5 Gy in 15 fractions). Three gold fiducials were implanted for image guidance. Patients were simulated and treated with a foley catheter and intrarectal balloon. A T2 magnetic resonance imaging scan was used for contouring, and a cine magnetic resonance imaging scan was used to calculate patient-specific internal target volume margins. Toxicity and quality-of-life data were collected using Common Terminology Criteria for Adverse Events v3.0 and the Expanded Prostate Cancer Index Composite. Results: 30 patients were accrued, 10 in each cohort. Median follow-up was 72 months. 60% had unfavorable intermediate-risk PCa. Two patients in the 15 Gy cohort developed late grade ≥3 gastrointestinal and genitourinary toxicity, with 1 patient suffering from a grade-4 rectal fistula after a rectal ulcer was biopsied repeatedly. Two patients had biochemical failure. Median PSA nadir was 0.4 ng/mL with 10 Gy, 0.09 ng/mL with 12.5 Gy and 0.07 ng/mL with 15 Gy. Median PSA at 4 years as well as proportion achieving a nadir <0.2 ng/mL improved significantly with higher doses. There was no significant change in quality of life from baseline in any of the domains, and the minimal clinically important change was not statistically different between the 3 cohorts. Conclusions: Other than a grade 4 toxicity, which may in part be due to repeated biopsies of a rectal ulcer, single-fraction SBRT boost was feasible and well tolerated. Larger studies are warranted to better document the outcomes of such an approach.

Original languageEnglish
Pages (from-to)1066-1073
Number of pages8
JournalInternational Journal of Radiation Oncology Biology Physics
Volume104
Issue number5
Early online date16 Apr 2019
DOIs
Publication statusPublished - 01 Aug 2019

ASJC Scopus subject areas

  • Radiation
  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Cancer Research

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    Alayed, Y., Loblaw, A., Chu, W., Al-Hanaqta, M., Chiang, A., Jain, S., Chung, H., Vesprini, D., Morton, G., Ravi, A., Davidson, M., Deabreu, A., Mamedov, A., Zhang, L., Erler, D., & Cheung, P. (2019). Stereotactic Body Radiation Therapy Boost for Intermediate-Risk Prostate Cancer: A Phase 1 Dose-Escalation Study. International Journal of Radiation Oncology Biology Physics, 104(5), 1066-1073. https://doi.org/10.1016/j.ijrobp.2019.04.006