TUESDAY, Sept. 13, 2005 (HealthDay News) -- High-dose radiation can cut prostate cancer recurrence by half, but it has no impact on survival rates, a new study found.
That lack of difference in survival rates may be due to the fact that prostate cancer is a slow-growing cancer, and the new study only looked at five years of data, said the study's lead author, Dr. Anthony Zietman, a professor of radiation oncology at Massachusetts General Hospital and Harvard Medical School. It might take as long as 10 to 20 years to see a difference, he explained.
In terms of cancer recurrence, however, higher-dose radiation showed a clear benefit, Zietman said.
"Men who had high-dose radiation were much less likely to have their cancer return than those with conventional radiation," he said. "And, because the technology has gotten very accurate, there was very little price to pay for the increased [radiation] dose, in terms of side effects," including impotence, he added.
The findings appear in the Sept. 14 issue of the Journal of the American Medical Association.
Almost two million American men are prostate cancer survivors, and more than 232,000 are diagnosed with the disease each year, according to the American Cancer Society. While as many as one in six men develops the disease over a lifetime, only one in 34 dies from it, the society said.
More than 26,000 American men choose radiation to treat their prostate cancer, according to background information in the article. Recurrence of prostate cancer, despite conventional radiation therapy, is common.
Zietman said during the past 10 years, radiation technology as improved dramatically, and doctors can now deliver higher doses of radiation more accurately than they could in the past.
To see if these higher doses of radiation could help prevent some cases of recurrence, Zietman and his colleagues compared 197 men who received conventional radiation to 195 who received high-dose radiation to treat early prostate cancer.
The average age of the men was 67 for the conventional group and 66 for the high-dose group. Most of the study volunteers were white.
Just over 61 percent of men on conventional radiation remained cancer-free after five years, while 80.4 percent of those treated with high-dose radiation had no cancer recurrence, the researchers found.
According to Zietman, the finding suggests that "men need to be asking radiation oncologists if they are just having conventional radiation, or if they're going to take advantage of the technology to deliver higher doses."
Dr. Theodore DeWeese, co-author of an editorial in the same issue of the journal and chairman of the department of radiation oncology and molecular radiation sciences at Johns Hopkins University School of Medicine, pointed out that not all hospitals can provide high-dose radiation yet.
He said the benefits of high-dose radiation generally outweigh the potential risks, "with the proviso that the physicians and the institution are capable of delivering these high doses safely." Right now, he said, that means getting treatment at larger medical centers. But, he added, smaller, community hospitals will likely have the technology soon as well.
"If you're otherwise healthy, with a life expectancy of at least 10 years, aggressive management of prostate cancer is likely to benefit you, and to reduce recurrence," DeWeese said.
Men need to discuss all the treatment options with their physician, and then decide which one has the most acceptable side-effect profile, he said.
To learn more about prostate cancer, visit the National Cancer Institute.