Study reveals image-guided adaptive radiation treatments linked to short-term side effects for prostate cancer
New Jersey, US: Radiation therapy for patients with prostate cancer can be made safer by a method that uses imaging technology as a guide. This method enables doctors to precisely direct radiation beams towards the prostate while avoiding adjacent tissue in the bladder, urethra, and rectum.
The technique is known as magnetic resonance-guided daily adaptive stereotactic body radiation (MRg-A-SBRT), and it has been the subject of a detailed study of all published clinical trials.
The findings of the study were published by Wiley online in CANCER, a peer-reviewed journal of the American Cancer Society.
MRg-A-SBRT's comprehensive images can be used to update a patient's radiation plan each day to take into account anatomical changes and to track the prostate's position in real-time while the radiation beam is on to make sure that the prostate is receiving the proper amount of treatment. Although MRg-A-SBRT is gaining popularity and has been the subject of numerous clinical research, it is unclear whether the method—which demands more time and resources than usual practices—had an influence on clinical results and side effects when compared to other radiation delivery methods.
To investigate, 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 total of 2,547 patients to evaluate side effects that occurred following MRg-A-SBRT for prostate cancer compared with a more conventional method of treatment that is guided by computed tomography and is not adjusted on a daily basis in the way that MRg-A-SBRT is.
MRg-A-SBRT was associated with significantly fewer urinary and bowel side effects in the short term following radiation. Specifically, there was a 44% reduction in urinary side effects and a 60% reduction in bowel side effects.
“The study is the first to directly evaluate the benefits of MR-guided adaptive prostate radiation in comparison to another more standard and conventional form of radiation, and it provides support for use of this treatment in the management of prostate cancer,” said Dr. Leeman.
Dr. Leeman noted that the study also raises further questions regarding this type of treatment. For example, will the short-term benefits lead to long-term benefits, which are more impactful for patients? Longer follow-up will help answer this question because MRg-A-SBRT is a relatively new treatment. Also, which aspect of the technology is responsible for the improved outcomes seen in clinical trials? “It could potentially be the capability for imaging-based monitoring during the treatment or it could be related to the adaptive planning component. Further studies will be needed to disentangle this,” said Dr. Leeman.
