MRI guidance significantly reduces radiotherapy side effects compared to CT
MRI-guided stereotactic body radiotherapy (SBRT) may be better than CT guidance when it comes to reducing treatment side effects in patients with prostate cancer.
A recent side-by-side comparison of the two modalities’ utility for guiding radiation therapy in a group of patients treated for prostate cancer shows numerous positives for MRI over CT. Researchers found that MRI guidance can significantly reduce long-term side effects associated with the treatment, especially those related to bowel and sexual health.
Experts came to this conclusion after conducting a secondary analysis of the phase 3 MIRAGE trial, which compares the use of both modalities for reducing toxicity following SBRT. The team analyzed data on treatment margins determined by each modality alongside patients’ side effects.
This revealed several clear benefits of MRI guidance. First, 14% fewer patients in the MR-guidance group experienced symptoms such as incontinence and painful urination. These are some of the more common symptoms reported following SBRT and they affected more than half of the CT guidance group.
CT guidance triggered significantly more gastrointestinal side effects. Almost 10% of patients in the CT-guided group experienced gastrointestinal toxicity, compared to just 1.4% in the MRI-guided group. Scores related to bowel and sexual health were much higher in the MRI-guided group as well.
These findings are likely owed to the reduced treatment margins afforded by MRI guidance, explains Amar Kishan, MD, executive vice chair of radiation oncology at the David Geffen School of Medicine at UCLA.
“This study adds strong evidence that the enhanced precision and accuracy afforded by MRI-guided SBRT leads to significantly fewer urinary, bowel, and sexual side effects for men receiving prostate SBRT,” Kishan, who serves as first author of the study, notes. “The MRI-guided approach, which includes real-time tracking of the prostate itself and the use of a built-in MRI to help deliver the radiation, allows us to use significantly narrower planning margins when delivering radiation, leading to less radiation to normal tissues. This in turn reduces the risk of enduring side effects that can impact a patient’s quality of life.”
The study abstract can be found here.
In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She began covering the medical imaging industry for Innovate Healthcare in 2021.