MONDAY, May 8 (HealthDay News) -- A radiation treatment commonly used in prostate cancer patients older than 55 works just as well in younger men with the same level of disease, a preliminary study finds.

The findings aren't yet definitive, and it's not clear if they'll lead to any changes in how prostate cancer is treated generally. But the study results do poke a hole in a common assumption that younger men need more aggressive treatment than older patients, said lead author Dr. Andre Konski, clinical research director of the Radiation Oncology Department at the Fox Chase Cancer Center in Philadelphia.

"Patients need to factor all risks and benefits, but external radiation should be given as a viable option for patients to consider," Konski said.

According to the American Cancer Society (ACS), prostate cancer is the second leading cancer killer for men. An estimated one in six men will receive a prostate cancer diagnosis in their lifetime, and more than 30,000 Americans currently die of the disease each year.

Prostate cancer tends to be more aggressive in younger patients, and doctors often respond with more drastic treatments, such as removal of the prostate.

In the new study, Konski and colleagues looked at how 84 men who underwent external beam radiation treatment for prostate cancer fared five years after their diagnosis.

They compared the outcomes of patients under 55 with those aged 60-69 and those 70 and older. All the men were in similar stages of the disease.

The study findings are expected to appear in the June 15 issue of the journal Cancer and were published online by the journal on Monday.

Konski's team found no statistically significant difference between how men in the three groups were doing at the five-year mark. Ninety-four percent of those in the youngest group were still alive, compared to 95 percent of those 60-69 and 87 percent of those 70 and older.

Also, between 96 percent and 98 percent of the living patients showed no signs of prostate cancer spread.

Konski cautioned that the results don't say anything about younger patients with more aggressive forms of prostate cancer. "They'll have potentially different outcomes," he said.

And he added that the study also doesn't mean that radiation is better than other treatments. However, the research does suggest that "when you have a younger man who has an earlier-stage disease, he would do as well as an older man does," Konski said.

Another expert said the study is still too short to draw definite conclusions. Dr. Durado Brooks, director of prostate cancer for American Cancer Society, noted that it can take a long time for prostate cancer to recur, "and while a five-year follow-up study is encouraging, it's by no means definitive."

As for choices about cancer treatment, "this is just one little piece of the puzzle," Brooks said. "We don't have enough definitive information to say this is the treatment you should choose."

In a related study, researchers in Iceland report finding a variant gene with strong links to prostate cancer.

As reported Monday by The New York Times, geneticists at DeCode Genetics say the gene is carried by about 13 percent of men of European ancestry and may raise a man's risk of developing prostate cancer by about 60 percent. The gene variant probably accounts for 8 percent of all cases of the disease, they said.

The gene is also twice as common in black men compared to whites, helping to explain "a significant part" of why prostate cancer strikes blacks more often than whites, DeCode's CEO Dr. Kari Stefansson told the Times. DeCode plans to develop a test aimed at spotting individuals who carry the gene and may be at special risk for prostate cancer.

The researchers reported their findings online Monday in the journal Nature Genetics.

More information

The National Cancer Institute can tell you more about prostate cancer.