23 August 2024
Two cancer patients at Mayo Clinic in Minnesota USA have responded well to minibeam radiation therapy (MBRT). This is the first time the therapy has been performed on humans.
Patient one, whose armpit tumour initially measured 14x14x11cm, reported a reduction in pain and an increase in mobility in the days following treatment. After three weeks the tumour had shrunk by 63%.
Patient two, whose 7x6x3cm ear tumour caused hearing loss and shooting pain, reported improved hearing and reduced pain in the days following treatment. Thirty-four days later, the tumour had completely flattened (see image).
MBRT is a new technique that targets cancers with alternating high-dose “peak” and low-dose “valley” radiation doses.
The Mayo Clinic team delivered radiation via a 12x12cm portable tungsten collimator, which was attached to the patient so that when the patient moved, the collimator moved with them. This set-up offers flexibility for patients with mobility issues, or those who find it difficult to stay still for extended periods.
MBRT in Australia is still a while away, with Mayo Clinic’s Radiation Oncology Medical Physicist, Michael Grams, saying the next step for researchers will be to determine the maximum tolerated dose rate. He says the team is also researching combinations of MBRT and systemic therapies like immunotherapy and chemotherapy.
The Mayo Clinic case studies were published in the Int. Journal of Radiation Oncology – Biology – Physics.
In March 2025, Mayo Clinic’s Director of Particle Therapy, Professor Anita Mahajan, will present the latest news from the Clinic’s proton beam therapy facility, at the ASMIRT/NZIMRT Conference in Adelaide. For more information, head to the conference website.
