The use of magnetic resonance (MR)-guided daily adaptive stereotactic body radiotherapy (SBRT) might make radiation therapy safer for patients with prostate cancer than standard computed tomography (CT)-guided SBRT by helping clinicians more accurately target the prostate while avoiding nearby healthy tissue, according to a new systematic review and meta-analysis published by Leeman et al in Cancer.
Background
By providing detailed images, MR-guided adaptive SBRT can be used to adjust patients’ radiation plans each day to account for anatomic changes and to monitor the real-time position of the prostate during the administration of radiotherapy. This may ensure that treatment is being directed accurately to the prostate.
Although it is becoming more popular and has been tested in multiple clinical trials, MR-guided adaptive SBRT requires more time and resources than standard procedures. Moreover, it is unclear whether the technique has an impact on clinical outcomes and side effects compared with other methods of delivering radiation.
Study Methods and Results
In the new study, investigators examined the data of 2,547 patients with prostate cancer from 29 clinical trials in order to determine the side effects that occurred following MR-guided adaptive SBRT compared with those that occurred after the more conventional CT-guided approach that is not adjusted on a daily basis. The investigators discovered that the MR-guided technique was associated with 44% fewer urinary side effects and 60% fewer bowel side effects shortly after treatment with radiation therapy.
Conclusions
“The study is the first to directly evaluate the benefits of [MR-guided daily adaptive SBRT] in comparison to another more standard and conventional form of radiation [therapy], and it provides support for use of this treatment in the management of prostate cancer,” highlighted lead study author Jonathan E. Leeman, MD, Assistant Professor of Radiation Oncology at Harvard Medical School and a physician in the Department of Radiation Oncology at the Dana-Farber Cancer Institute and Brigham and Women’s Hospital.
The investigators noted that their findings raised further questions regarding the new treatment strategy. For instance, will the short-term benefits lead to long-term benefits, which are more impactful for patients? The investigators hope that longer follow-up will help them answer these questions.
Despite MR-guided adaptive SBRT being a relatively new treatment, Dr. Leeman concluded that aspects of the technique that might be responsible for the improved outcomes seen in clinical trials “could potentially be the capability for imaging-based monitoring during the treatment or … could be related to the adaptive planning component.” Further studies may be needed to more fully understand its benefits.
Disclosure: For full disclosures of the study authors, visit acsjournals.onlinelibrary.wiley.com.
