Acute toxicity of SBRT in localized prostate cancer: A Spanish multicenter study

Stereotactic body radiation therapy (SBRT) has emerged as an effective option for the treatment of localized prostate cancer; however, data from real-world clinical practice remain limited.

Between January 2020 and December 2023, 251 patients with localized prostate cancer treated with SBRT were included in 12 centers in Spain. The treatment volume included prostate ± seminal vesicles, without prophylactic pelvic radiotherapy. A dose of 35-40 Gy was prescribed in 5 fractions, every other day. Acute genitourinary (GU), gastrointestinal (GI) and sexual toxicity was assessed up to 6 months post-treatment using the Common Terminology Criteria for Adverse Events (CTCAE) v5.0.

A total of 251 patients were classified based on the National Comprehensive Cancer Network (NCCN®) classification. Four percent of patients had very low-risk disease, 26.3% low-risk, and 66.5% intermediate-risk (27.1% favorable intermediate and 39.4% unfavorable intermediate). Additionally, 2.8% were classified as high-risk and 0.4% as very high-risk. The median patient age was 72 years (range: 65-76), and the baseline PSA was 6.7 ng/ml (range: 5.3-8.7). The median SBRT dose was 40 Gy (range: 35-40 Gy). Grade 2 acute GU toxicity occurred in 6.4% of patients, and grade 3 in 0.4%. Grade 2 GI toxicity was observed in 0.8%, with no cases of grade 3 GI toxicity. Regarding sexual toxicity, 11.2% of patients experienced grade 2, and 1.2% grade 3 toxicity.

Five-fraction SBRT is a feasible and safe treatment with a low incidence of acute toxicity.