Stereotactic Radiation Therapy versus Brachytherapy: Relative Strengths of Two Highly Efficient Options for the Treatment of Localized Prostate Cancer

SIMPLE SUMMARY: Stereotactic radiation therapy consists of delivering ablative ultra-high doses of radiation to a precise target in a very limited number of fractions. Because of its ability to drastically shorten treatment duration and its potential radiobiological advantage, interest in this technique for the treatment of localized prostate cancer has increased over the past decade. At the same time, brachytherapy remains a time-tested technique that has excellent, proven outcomes with a very long follow-up, setting a standard of treatment for all subsets of the disease and a reference against which emerging techniques should be compared. We propose a critical literature review to report on the respective levels of evidence of stereotactic radiation therapy and brachytherapy for the treatment of localized prostate cancer. ABSTRACT: Stereotactic body radiation therapy (SBRT) has become a valid option for the treatment of low- and intermediate-risk prostate cancer. In randomized trials, it was found not inferior to conventionally fractionated external beam radiation therapy (EBRT). It also compares favorably to brachytherapy (BT) even if level 1 evidence is lacking. However, BT remains a strong competitor, especially for young patients, as series with 10–15 years of median follow-up have proven its efficacy over time. SBRT will thus have to confirm its effectiveness over the long-term as well. SBRT has the advantage over BT of less acute urinary toxicity and, more hypothetically, less sexual impairment. Data are limited regarding SBRT for high-risk disease while BT, as a boost after EBRT, has demonstrated superiority against EBRT alone in randomized trials. However, patients should be informed of significant urinary toxicity. SBRT is under investigation in strategies of treatment intensification such as combination of EBRT plus SBRT boost or focal dose escalation to the tumor site within the prostate. Our goal was to examine respective levels of evidence of SBRT and BT for the treatment of localized prostate cancer in terms of oncologic outcomes, toxicity and quality of life, and to discuss strategies of treatment intensification.