A new radiotherapy technique could help doctors to focus treatment more precisely on tumors in the bladder and reduce damage to surrounding healthy tissue. Researchers showed that pretreatment imaging using magnetic resonance imaging (MRI) was effective at guiding radiotherapy toward tumors in the bladder. Taking regular MRI scans of a tumor’s position helped to ensure that treatment to urinary bladder cancers could be delivered accurately during a course of radiotherapy. Their findings were published by Vestergaard et al in Radiotherapy & Oncology.
Making sure that radiation hits the tumor site—while avoiding healthy, unaffected tissue—is a key focus for radiotherapy research. Precision radiotherapy has seen huge advances in this area, but challenges remain. In bladder cancer, the area requiring treatment can shift quickly, depending on how much a patient drinks or how full the bladder is.
Researchers at The Institute of Cancer Research, London, The Royal Marsden NHS Foundation Trust, and Aarhus University Hospital in Denmark used MRI scans to provide detailed pictures of bladder cancers and healthy soft tissue. They used these images to adapt the radiotherapy dose before treatment, and then used scans to check the position of the tumor throughout the 10 minutes of treatment time that followed.
They found that the “adapted” treatment successfully targeted the tumor throughout the course of treatment while minimizing the impact on surrounding tissue.
Uwe Oelfke, PhD, Head of the Joint Department of Physics at the Institute of Cancer Research and The Royal Marsden, said, “Currently, patients are scanned before a course of radiotherapy to determine the location of the tumor in the bladder. Margins around the tumor are also treated to hopefully account for any tumor movement. It is less accurate than this new, improved method that recalculates and optimizes treatment based on the images taken before treatment is delivered. This study shows that such reoptimized plans can accurately treat patients. In the future, we expect that monitoring the treatment with MRI throughout a radiotherapy fraction on MRI-guided radiotherapy machines, such as our new MR Linac, will ensure accurate delivery and further reductions in safety margins.”
The researchers believe that MRI-guided adaptive radiotherapy will be a significant step forward in future radiotherapy treatment of patients with urinary bladder cancer.
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