Study Questions Radiation Use for 'Low-Risk' Prostate Cancers
Upping the dosage didn't alter survival rates for men with these slow-growing tumors
FRIDAY, July 17, 2015 (HealthDay News) -- Higher doses of radiation may improve survival in men with medium- and high-risk prostate cancers, but it does not do the same for those with low-risk disease, a new study suggests.
As is the case with many cancers, doctors must balance the risks and side effects of radiation therapy against its potential benefits when deciding if it's right for a particular patient.
When it comes to prostate cancer, "surgery and radiation treatments remain equal options for men with this disease," noted Dr. Louis Potters, chair of the department of radiation medicine at North Shore-LIJ Health System in Great Neck, N.Y.
So when is radiation warranted, and at what dose, based on the aggressiveness of the tumor?
The new study, led by radiation oncology resident Dr. Anusha Kalbasi of the University of Pennsylvania, looked at the issue using data from more than 42,000 prostate cancer patients.
Some of the men had received the standard dose of radiation, while others received higher-dose radiation.
The researchers found that every incremental increase in radiation dose was associated with a 7.8 percent decline (for those with medium-risk cancer) and 6.3 percent decline (for high-risk cancer) in the rate of death for the men from any cause.
However, the equation changed when it came to men with slower growing, "low-risk" prostate tumors. In those cases, using a higher dose of radiation made no difference in survival rates, according to the study published July 16 in JAMA Oncology.
The researchers noted that low-risk prostate cancer was the most common type of prostate cancer diagnosed in the United States in 2014, affecting about 150,000 men.
Therefore, the study "raises the provocative question of whether radiation dose reduction for patients with low-risk prostate cancer could achieve similar cure rates while avoiding the increased risk of side effects associated with higher radiation doses," Kalbasi said in a university news release.
Study senior author Dr. Justin Bekelman, a professor of radiation oncology at the university, believes that "the dose of radiation should be personalized to the specific characteristics of the prostate tumor."
"For some patients, personalized treatment will lower the chances of toxicity while maintaining similar survival rates; for other patients, personalized treatment will mean escalating radiation dose to achieve the highest survival while protecting normal tissues, like the bladder and rectum," he explained in the news release.
Potters agreed. "These results allow one's physician to consider personalized doses of radiation therapy based on the underlying nature of a patient's cancer," he said.
"It also begs the question of the role of any treatment for low-risk disease, where active surveillance may be the best initial approach," Potters said. Active surveillance, often called "watchful waiting," means that the patient is not treated but simply monitored over time to check for any suspicious changes in the prostate tumor.
Dr. Jonathan Haas is chief of radiation oncology at Winthrop-University Hospital in Mineola, N.Y. He described the new study as "excellent," and said the field of prostate cancer care is already moving towards "more accurate [radiation] treatments and a shorter treatment time -- which translates into better medicine and more convenience for the patient."
The American Cancer Society has more about prostate cancer.