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Sandy Srinivas, MD


ASTRO 2023: Fewer, Higher Doses of SBRT for Localized Prostate Cancer

By: Chris Schimpf, BS
Posted: Thursday, October 5, 2023

Higher doses of radiation therapy delivered over five treatment sessions may be as effective in treating prostate cancer as more sessions of lower doses delivered over several weeks, according to the results of the randomized phase III PACE-B trial presented this week at the 2023 American Society for Radiology Oncology (ASTRO) Annual Meeting (Abstract LBA 03). According to Nicholas van As, MD, of The Royal Marsden NHS Foundation Trust, London, and colleagues, stereotactic body radiation therapy (SBRT) demonstrated a 5-year 96% disease control rate in patients whose prostate cancer had not spread, versus 95% for conventional radiation therapy. The researchers recommended that patients with intermediate-risk prostate cancer be offered this alternative to longer courses of radiation therapy or surgery.

“One of the things this study demonstrated is that outcomes of high-quality radiation therapy are outstanding,” said Dr. van As in an ASTRO press release. “Standard radiation treatment is already highly effective and is very well tolerated in people with localized prostate cancer. But for a health-care system and for patients to have this treatment delivered just as effectively in 5 days as opposed to 4 weeks has huge implications.”

A total of 874 patients with prostate cancer (median age = 69.8 years) who either preferred radiation treatment or were unsuitable for surgery were included in the study, drawn from 38 centers across the United Kingdom and Canada. They received either SBRT (n = 433), consisting of five fractions over 1 to 2 weeks (36.25 Gy total dose), or standard radiation therapy (n = 441), consisting of 39 fractions over 7.5 weeks (78 Gy) or 20 fractions over 4 weeks (62 Gy). None received hormonal therapy, and the median follow-up was 73.1 months.

Five years after treatment, patients treated with SBRT had a biochemical clinical failure event-free rate of 95.7% versus 94.6% with conventional radiation therapy. Side effects were considered to be few and not significantly different in both treatment groups.

Disclosure: Dr. van As reported no conflicts of interest.

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