A breakthrough in radiation therapy may cut down the time localized prostate cancer patients spend healing.
When we think of radiation therapy, most of us envision what is known in the trade as external beam radiotherapy. It's the familiar image of a patient laying back while the cancerous portion of his body is hit up by invisible ionizing radiation projected from a nearby machine.
There is another type of radiation therapy, however, that's a little less flashy but has been proven effective for men with localized prostate cancer. Known as internal radiation therapy, or brachytherapy, it makes use of tiny radioactive implants surgically inserted in or near the cancerous tissue. The big advantage to this type of therapy is that it limits exposure of surrounding healthy tissue to the radiation – a crucial consideration when combating prostate cancer, given the other organs in the prostate's neighborhood. With this is mind, the radioactive seeds have typically been compounded at a low dose rate (LDR), but left inside the patient for a relatively long period of time.
Radiation oncologists measure their doses of ionizing radiation in units called grays (Gy). Low dose rates of less than 1.8 to 2 Gy per session, or “fractionation,” are common. The procedure plays out to a total dose of 60 to 80 Gy usually, across five fractionations a week.
Now new research out of Oakland University’s William Beaumont School of Medicine in Royal Oak, Michigan may be pointing to a better way. In their study, patients who received a single fractionation of 19 Gy HDR brachytherapy experienced similar clinical outcomes as with LDR brachytherapy, but with the convenience of a single visit.
“It is becoming apparent that patients may be treated definitively for their prostate cancer in as little as a single day with a minimally invasive outpatient procedure,” said lead study author Daniel J. Krauss, MD, a radiation oncologist. “We found that patients generally can resume normal activities the following day with typical side effects.”
The study presented the results of a non-randomized, prospective clinical trial of 58 patients with low- or intermediate-risk prostate cancer, with a median follow-up period of 2.9 years. All patients received a single, 19 Gy fraction of HDR brachytherapy. The median patient age was 63 years.
“This study illustrates that a potentially curative dose of radiation may be delivered safely to the prostate entirely in a single administration,” said Krauss. “Giving the entire dose in a single treatment theoretically could have had a greater negative impact on the normal tissues in close proximity to the prostate—meaning the bladder, urethra and rectum—but this was not found to be the case. Toxicity rates were extremely low, with essentially no major complications encountered in this initial group of 58 patients.”
The study was published in the International Journal of Radiation Oncology.