Stereotactic body radiotherapy (SBRT) may benefit patients with high-risk prostate cancer (PCa), according to data from a pooled analysis published in the International Journal of Radiation Oncology, Biology, Physics.
The investigators pooled data for 344 patients from a consortium of 7 institutions with phase 2 clinical trials and prospective registries. Analyses were limited to men receiving SBRT for high-risk PCa with at least 24 months of follow-up. Most patients (72%) received androgen deprivation therapy.
The estimated 4-year biochemical recurrence-free survival (BCRFS) rate and distant metastasis-free survival (DMFS) rates were 81.7% (95% CI, 77.2%-86.5%) and 89.1% (95% CI, 85.3%-93.1%), respectively.
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The study authors noted that the 4-year BCRFS rate in this analysis was similar to the 5-year BCRFS rates for patients enrolled on the phase 3 ASCENDE-RT trial (NCT00175396) who received a brachytherapy boost (85.5%) or dose-escalated conventionally fractionated radiotherapy alone (83.6%) in addition to 12 months of ADT.
Eighteen percent and 5% of patients were found to have acute grade 2 or higher genitourinary (GU) or gastrointestinal (GI) toxicity, respectively. No patients had acute grade 3 or greater GU or GI toxicities.
A late-grade toxicity evaluation demonstrated a 4-year cumulative incidence estimate of 17.6% for late-grade 2 or higher GU toxicity and 6.4% for GI toxicity. Late-grade 3 GU toxicity had a crude incidence rate of 2.3% and late-grade 3 GI toxicity, a crude incidence rate of 0.9%.
The study authors noted that these data support a “favorable” toxicity and efficacy profile for SBRT for high-risk PCa, but cautioned that this analysis cannot provide level I evidence to support SBRT for high-risk PCa due to its nonrandomized nature.
Disclosures: One of the study authors disclosed financial relationships with the pharmaceutical industry and/or the medical device industry. For a full list of disclosures, please refer to the original study.
Reference
van Dams R, Jiang NY, Fuller DB, et al. Stereotactic body radiotherapy for high-risk localized carcinoma of the prostate (sharp) consortium: analysis of 344 prospectively treated patients. Int J Radiat Oncol Biol Phys. Published online January 22, 2021. doi:10.1016/j.ijrobp.2021.01.016
