The effectiveness and safety of stereotactic body radiotherapy (SBRT), proton therapy (PT), and irreversible electroporation (IRE) for localized prostate cancer

Abstract

Purpose

This systematic review evaluates the effectiveness and safety of three innovative treatments – stereotactic body radiotherapy (SBRT), proton therapy (PT), and irreversible electroporation (IRE) – against existing treatments for localized prostate cancer.

Methods and materials

We performed a systematic review based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, considering articles on patient-relevant outcomes (quality of life, survival and safety) published between February 2018 and February 2024 in English or German.

Results

Randomized controlled trials (RCTs) could not be identified for IRE and PT, preventing definitive effectiveness assessments. The evidence on IRE from five observational studies (n ​= ​846) is insufficient for conclusive toxicity evaluations. For PT, eight observational studies (n ​= ​5514) show inconsistent gastrointestinal (GI) and genitourinary (GU) toxicity trends, with long-term data indicating persistent GI symptoms and a significant increase in severe GU toxicities. For SBRT, three RCTs (n ​= ​2138) and two observational studies (n ​= ​460) could be found. The results show minor, non-significant differences in survival rates compared to conventional fractionation, a type of external radiation, after two and five years. Cumulative grade ≥1 GI toxicity with SBRT was significantly lower than with conventional fractionation at treatment end and at one year. Initial GU acute toxicities were lower in the SBRT group but not significantly different after one year. Observational data confirms low initial GU acute toxicities, aligning with RCT trends by three months.

Conclusions

The evidence for SBRT, PT, and IRE in treating localized prostate cancer is inconclusive. While it is unclear whether these therapies can replace more invasive procedures like prostatectomy or significantly improve quality of life or survival, SBRT appears as effective as conventional fractionation for survival outcomes in low-to intermediate-risk patients. Further RCTs are needed to evaluate the long-term effectiveness and safety of these treatments compared to standard methods.