Mayo Clinic Develops Innovative Minibeam Therapy for Resistant Cancers
Researchers at Mayo Clinic have announced promising outcomes from the application of a novel radiation therapy technique known as minibeam radiotherapy in treating patients with cancers resistant to existing therapies. This groundbreaking technique delivers high radiation doses through narrowly focused beams, minimizing exposure to healthy surrounding tissue.
In a study published in the International Journal of Radiation Oncology, Biology, Physics, symptoms improved in 86% of patients treated with this method. Out of 40 tumors assessed, 22.5% disappeared entirely, 25% showed reduction, and 45% remained stable. These results indicate that minibeam radiotherapy may not only change the delivery of radiation but also potentially enhance the biological response of tumors.
Michael Grams, PhD, co-first author of the study and a radiation oncology medical physicist, stated that the higher radiation doses were well-tolerated by patients with resistant cancers. He also suggested that the therapy might work synergistically with the body’s immune system. This interaction could provide an alternative approach to treating challenging cancer cases.
The Mayo Clinic team developed the minibeam technology five years ago. It employs a tungsten collimator to divide a traditional radiation beam into multiple narrow beams. This setup generates a pattern of high and low radiation areas, facilitating better recovery of healthy tissue. The technique also streamlines treatment protocols, reducing the number of required sessions significantly.
In a clinical trial involving 36 patients with hard-to-treat cancers like melanomas, squamous cell carcinomas, and soft tissue sarcomas, minibeam therapy achieved an estimated local control rate of 89% at 12 months. Patients reported significant relief in symptoms including pain and bleeding, with improved daily functioning. The observed side effects were notably less severe than conventional radiation treatments at similar doses.
An intriguing finding was the occurrence of an abscopal effect, where 11% of patients showed tumor response in areas not targeted by minibeam radiotherapy. This suggests a potential interaction with the immune system, leading to systemic therapeutic effects.
Scott Lester, MD, emphasized the importance of this therapy in cases where conventional options are ineffective, highlighting its potential to support healing while battling cancer. The team is continuing laboratory studies to understand the immune mechanisms involved and is conducting Phase 1 trials to evaluate different dosage levels. They are also exploring the application of the therapy in early-stage breast cancer and during surgery for unresectable pancreatic cancer.
Dr. Grams expressed optimism about the therapy's potential, stating that ongoing research aims to identify the best contexts for its use in treating complex cancers.