Precise Radiation Destroys Spreading Tumors
U.S. researchers found precise radiation therapy can destroy tumors that have spread to other parts of the body, a move that adds years to the life of a patient desperate for help.
Scientists said Wednesday, the new radiation techniques can attack metastases, defined as tumors that have spread one by one.
"This was proof of principle in patients who had failed the standard therapies and had few, if any, remaining options," said Dr. Ralph Weichselbaum of the University of Chicago Medical Center, who led the study.
Experiments in 29 patients showed the radiation stopped all the tumors in six, or 21 percent, of the patients, lasting between 10 months and more than two years.
The study found inconsistent results in another six patients, only the treated tumors grew, while in yet another six, untreated tumors remained and grew.
The team at the University of Chicago Medical Center reported the findings in the journal Clinical Cancer Research.
New tumors appeared but the treated tumors were stopped in eight of the patients.
Weichselbaum said higher doses of radiation are safe for many places on the body and might work better.
Patients with a variety of cancers, including lung, head and neck, breast, colon and ovarian, are being treated now with higher doses and are living longer lives.
All have stage IV cancer, meaning it has spread to more than one place throughout the body. Almost all patients with stage IV cancer die, even with chemotherapy, except for patients with testicular cancer and some blood cancers.
"These patients had been through experimental treatments, so it is not like we got anybody who had standard of care left, Weichselbaum said.
Each volunteer got three doses of precisely targeted radiation to their tumors. New guided radiation techniques can limit the amount of damage to healthy tissue and new imaging techniques, such as CT and PET scans, can help doctors find tumors they previously might have missed.
The patients reported fatigue but few had serious side effects. One developed severe vomiting and another had internal bleeding that required a blood transfusion.
"Although our radiation wasn’t able to control the disease in everybody, if we had treated where they had recurred with further radiation, surgery or other types of ablation, they could have been rendered disease-free," said Dr. Joseph Salama, who worked on the study.
"Not all metastatic cancer is the same. In some people, more aggressive therapy can potentially be beneficial," Salama added.
Ten patients out of the original 29 are still alive, Salama said. They found nine lived more than 20 months.
Doctors are treating more patients with higher doses of radiation now and of 51 patients treated so far, 15 are alive.
The researchers want to find a common genetic signature to identify patients who could possibly benefit from this radiation.
Weichselbaum said one concern is whether chemotherapy needs to destroy tiny tumor seeds that spread and grow into metastases.
"Most likely this will be used with the targeted therapies," he said.
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