Greater Precision with MRI-guided Prostate Cancer Radiotherapy
Men undergoing MRI-guided radiotherapy for localised prostate cancer, had fewer toxicities and better quality of life, according to new research published in JAMA Oncology. This was the first randomised phase III clinical trial to directly compare MRI-guided stereotactic body radiotherapy (SBRT) with the same therapy guided by CT.
“MRI guidance offers several advantages over standard CT guidance, most notably the ability to dramatically reduce planning margins, providing more focused treatment with less injury to nearby normal tissues and organs,” said lead author Amar Kishan, MD, a radiation oncologist. “MRI technology is more costly than CT, both in terms of upfront equipment expenses and longer treatment times, which is one reason our study set out to determine if MRI-guided technology offers tangible benefits for patients.”
SBRT for prostate cancer usually delivers radiation in five or fewer precisely targeted doses. It is an established and generally well tolerated form of treatment, but it can cause toxicities resulting in urinary, bowel and sexual dysfunction. This UCLA-led clinical trial included 154 analysable patients with prostate cancer who were randomised to either a CT-guidance arm (76 patients) or an MRI-guidance arm (78 patients).
This study included assessment by both physicians and patients. From both perspectives, MRI-guided therapy was associated with fewer side effects and better quality of life over at least three months of follow-up.
“In this trial, we demonstrated that the reduction in treatment volumes facilitated by MRI guidance leads to a significant reduction in moderate physician-scored toxicity and to a reduction in the proportion of patients noting significant decrements in patient-reported outcome metrics in the near term,” said Dr Kishan. “Although additional studies will need to confirm these benefits over time, we’re hopeful that these results will lead to better outcomes for men with prostate cancer.”
The 2mm margin used with MRI-guidance in the trial is narrower than has been used in any previous large study. Unlike CT, MRI technology can monitor prostate motion directly, and it offers improved soft tissue contrast, improving the accuracy of alignment prior to radiation.
Source: University of California – Los Angeles Health Sciences