UCLA researchers have found that men with low- or intermediate-risk prostate cancer can safely undergo higher doses of radiation over a significantly shorter period of time and still have the same, successful outcomes as from a much longer course of treatment. This type of radiation, known as stereotactic body radiotherapy, is a form of external beam radiation therapy and reduces the duration of treatment from 45 days to four to five days. The approach has been in use since 2000, but has not yet been widely adopted because of concerns over how safe and effective this approach would be in the long term.
“Most men with low- or intermediate-risk prostate cancer undergo conventional radiation, which requires them to come in daily for treatment and takes an average of nine weeks to complete,” says radiation oncologist Amar Kishan, MD. “That can be very burdensome on a patient and be a huge interruption in their life. With the improvements being made to modern technology, we’ve found that using stereotactic body radiotherapy, which has a higher dose of radiation, can safely and effectively be done in a much shorter time frame without additional toxicity or compromising any chance of a cure.”
The UCLA research team analyzed data from 2,142 men with low- or intermediate-risk prostate cancer across multiple institutions who were treated with stereotactic body radiotherapy for prostate cancer between 2000 and 2012. The men were followed for a median of 6.9 years. Just over half of the men had low-risk disease (53 percent), 32 percent had less aggressive intermediate-risk disease, and 12 percent had a more aggressive form of intermediate-risk disease.
The recurrence rate for men with low-risk disease was 4.5 percent, the recurrence rate for the less aggressive intermediate risk was 8.6 percent, and the recurrence rate for the more aggressive intermediate-risk group was 14.9 percent. Overall, the recurrence rate for intermediate-risk disease was 10.2 percent. These are essentially identical to rates following more conventional forms of radiation, which are about 4 percent to 5 percent for low-risk disease and 10 percent to 15 percent for intermediate-risk disease.
The research team at the UCLA Jonsson Comprehensive Cancer Center had previously found that stereotactic body radiation therapy was more cost effective because of the fewer treatments involved. Other research has also suggested psychological benefits, such as less regret about undergoing treatment. The current study now provides long-term data regarding the safety and clinical efficacy of this approach.
Dr. Kishan says the data show that the majority of the men followed are free of prostate cancer seven years after treatment. He added that there was no evidence that this therapy caused worse toxicity in the long term. “In fact,” Dr. Kishan says, “we not only confirm that this method is both safe and effective, but we provide significant evidence that this could be a viable treatment option for men with low and intermediate risk of prostate cancer.”
For more information, visit UCLA Kidney Care Program website.