A method that uses imaging technology as a guide could make radiation therapy safer for patients with prostate cancer by helping clinicians accurately aim radiation beams on the prostate while avoiding nearby tissue within the bladder, urethra, and rectum. That’s the finding of an intensive evaluation of all published clinical trials of the technique, called magnetic resonance–guided every day adaptive stereotactic body radiotherapy (MRg-A-SBRT). The evaluation is published by Wiley online in CANCER, a peer-reviewed journal of the American Cancer Society.

By providing detailed images, MRg-A-SBRT will be used to regulate a patient’s radiation plan on daily basis to account for anatomical changes and to watch the position of the prostate in real time while the radiation beam is on to make sure that treatment is being directed accurately to the prostate. Although MRg-A-SBRT is gaining popularity and multiple clinical trials have tested it, it’s unclear whether the technique, which requires more time and resources than standard procedures, has an impact on clinical outcomes and unwanted side effects compared with other ways of delivering radiation.

To analyze, Jonathan E. Leeman, MD, of the Dana-Farber Cancer Institute and Brigham and Women’s Hospital, and his colleagues searched the medical literature for prospective studies that tested MRg-A-SBRT. The team combined data from 29 clinical trials that included a complete of two,547 patients to judge unwanted side effects that occurred following MRg-A-SBRT for prostate cancer compared with a more conventional approach to treatment that’s guided by computed tomography and isn’t adjusted each day in the way in which that MRg-A-SBRT is.

MRg-A-SBRT was related to significantly fewer urinary and bowel unwanted side effects within the short term following radiation. Specifically, there was a 44% reduction in urinary unwanted side effects and a 60% reduction in bowel unwanted side effects.

The study is the primary to directly evaluate the advantages of MR-guided adaptive prostate radiation as compared to a different more standard and traditional type of radiation, and it provides support to be used of this treatment within the management of prostate cancer.”

Dr. Jonathan E. Leeman, MD, Dana-Farber Cancer Institute and Brigham and Women’s Hospital

Dr. Leeman noted that the study also raises further questions regarding this sort of treatment. For instance, will the short-term advantages result in long-term advantages, that are more impactful for patients? Longer follow-up will help answer this query because MRg-A-SBRT is a comparatively recent treatment. Also, which aspect of the technology is liable for the improved outcomes seen in clinical trials? “It could potentially be the aptitude for imaging-based monitoring through the treatment or it could possibly be related to the adaptive planning component. Further studies shall be needed to disentangle this,” said Dr. Leeman.

An accompanying editorial discusses the evaluation’ findings, weighs the potential advantages and shortcomings of adopting this treatment strategy for patients, and questions the worth of broad adoption.