When it involves limiting unintended effects from radiation therapy, precision is the secret. Doctors need to treat cancer while sparing healthy tissue, and fortunately technological advances are making this increasingly possible.
A brand new technique called stereotactic body radiotherapy (SBRT) can focus a beam of high-dose radiation on the tumor from almost any direction.
A full course of therapy requires only five individual treatments over two weeks, making SBRT more convenient than earlier low-dose methods that require more clinic visits. Treatment relies on special kinds of medical imaging scans that allow doctors to see where the cancer is within the body.
Advances in technology
Recently, doctors have begun to mix SBRT with imaging scans that may visualize tumor movement in real time. Simple movements reminiscent of respiration, swallowing, or digesting food can change the position of the tumor. But this recent technique—called magnetic resonance-guided day by day adaptive SBRT, or MRG-A-SBRT for brief—consistently adjusts for those movements, so doctors can stay heading in the right direction. Can focus more clearly.
now, A new study This helps confirm that MRg-A-SBRT has fewer unintended effects than a related method called CT-SBRT, which uses computed tomography for imaging.
Analysis of studies
During the brand new study, Dr. Lemon and colleagues searched the clinical literature for each published clinical trial up to now evaluating SBRT for prostate cancer, with either MRI or CT guidance. (This sort of study is known as a scientific review.)
The team ultimately identified 29 clinical trials that monitored outcomes in a complete of greater than 2,500 patients. Short-term data on unintended effects were collected for a mean of three months after the procedure was accomplished.
Leeman's team used statistical methods to aggregate study results into combined datasets. They found that patients treated with MR-SBRT had fewer unintended effects. Specifically, 5% to 33% of men treated with MR-SBRT had genitourinary unintended effects, compared with between 9% and 47% of men treated with CT. Similarly, the danger of gastrointestinal unintended effects in men treated with MR-SBRT ranged from 0% to eight%, compared with between 2% and 23% in men treated with CT.
Results and comments.
The authors concluded that “technological advances in the delivery of health-related radiotherapy provided by MRG-A-SBRT translate into measurable clinical benefit” (i.e., higher tolerated treatment). But exactly why the treatment was higher tolerated is unclear. Is it because MR scanning has higher resolution? Does adaptive planning (and real-time targeting) account for the reduced risk of unintended effects, or can or not it’s attributed to some combination of those aspects? Adaptive planning is a “potentially important differentiator,” says Dr. Lemon, but adds that more studies are needed to substantiate where the advantages come from.