Rating Radiation For Prostate Cancer
External radiation therapy may cut survival rates for men with early-stage prostate cancer.
These men are more likely to die over the next five years than those treated with radioactive seed implants or surgery to remove the prostate, a new study suggests. But even radiation treatment was highly effective, the researchers say.
After five years, 96 percent of the men who received seed implants and 98 percent of those who had surgery were still alive, they report. In contrast, 94 percent of the men who received external radiation were alive.
The findings suggest that over the long term, the three treatments are not
necessarily equivalent in terms of overall survival, says researcher Jay Ciezki, M.D., a radiation oncologist at The Cleveland Clinic. The study was presented at the 2007 Prostate Cancer Symposium in Kissimmee, Fla.
The researchers studied 2,285 men with early-stage cancer that was still confined to the prostate — a group that accounts for about 80 percent of men diagnosed with the disease. Of the total, 1,053 men had surgery to remove the prostate. Six hundred sixty-two were treated with seed implant therapy, or brachytherapy, in which surgeons permanently implant tiny radioactive seeds into the prostate gland.
The rest got external radiation therapy, usually with a newer type of treatment known as intensity modulated radiation therapy, or IMRT, in which multiple beams are focused at the prostate from many directions.
A computerized program allows doctors to adjust both the strength and the intensity of the beams so that more radiation is blasted at the tumor and less is delivered to critical surrounding organs such as the bladder and rectum.
After taking into account other factors that raise the risk of dying (chiefly age, other illnesses and smoking) the results showed that the difference in survival rates among men given seed implants and surgery could have been due to chance. But external beam radiotherapy proved inferior to either of them, Ciezki says.
Eric Klein, M.D., head of urologic oncology at The Cleveland Clinic, says that all things being equal, surgery or seed implants are the treatments of choice for most men. That said, radiation therapy should not be abandoned, doctors say.
Some men may not be fit enough for surgery or even the minor surgery associated with seed implant therapy, says Deborah Kuban, M.D., a radiation oncologist at the University of Texas M.D. Anderson Cancer Center in Houston. For them, radiation is still the best option, she tells WebMD.
Radiation is also the treatment of choice if the disease has started to spread to the edges of the prostate or the lymph nodes, she adds. To be able to offer a cancer patient a treatment that has a 94 percent cure rate is wonderful, she tells WebMD.
The researchers say they are continuing to follow the men to see if the difference in survival rates persists over time. They are also trying to figure out why the men who got radiation didn't do as well. One possibility is that despite newer techniques, some of the radiation missed its target, damaging nearby tissue, says Klein. This, in turn, can cause inflammation of the blood vessels, which can lead to blockages in or hardening of the arteries, he tells WebMD.
By Charlene Laino
Reviewed by Louise Chang, M.D.
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