(AP) -- Doctors are reporting a key advance in treating men with cancer that has started to spread beyond the prostate: survival is significantly better if radiation is added to standard hormone treatments.
Results of the study were given Sunday at a cancer conference, where other research showed that an experimental drug boosted survival for women with very advanced breast cancer. The drug is being reviewed by the federal Food and Drug Administration.
The prostate study has the potential to change care right away. About 20 percent of the nearly 200,000 men diagnosed with the disease each year in the United States are like those in the study - with cancer that has spread to the area around the prostate.
"It is this group of patients in whom many of the deaths from prostate cancer occur," because the condition is usually incurable, said study leader Dr. Padraig Warde, a radiation expert from the University of Toronto's Princess Margaret Hospital.
These men are treated with drugs that block testosterone, a hormone that helps prostate cancer grow. Only about half also get radiation because of concerns about urinary problems it can cause. Even though these treatments have been used for decades, few studies have been done to establish their value alone or in combination.
The new study assigned 1,200 men to get hormones plus radiation or hormones alone. After seven years, 74 percent of men receiving both treatments were alive versus 66 percent of the others. Those on both treatments lived an average of six months longer than those given just hormones.
Serious side effects occurred in less than 2 percent of men in either group. The study was sponsored by the National Cancer Institute of Canada.
The results show that "radiation is an indispensable element in the treatment of patients with high-risk prostate cancer," said Dr. Jennifer Obel, a cancer specialist at Northshore University Health System in suburban Chicago who had no role in the study.
Dr. Otis Brawley, the American Cancer Society's chief medical officer, praised the survival advantage but said he wished it were larger.
"It's a practice-changing study in certain countries," especially in Europe, where more men are diagnosed with locally advanced tumors than in the United States, he said.
In the U.S., about 192,280 new cases of prostate cancer were diagnosed last year, and it claimed 27,360 lives.
The breast cancer study tested eribulin, a drug derived from a sea sponge. Unlike Herceptin and other gene-targeted drugs that have been the focus of cancer research for the past decade, this one is a chemotherapy - a drug that kills cancer cells, in this case by attacking cell division in a novel way.
The study tested it in 762 women whose cancer had either recurred after initial treatment or had spread beyond the breast. All were getting worse despite having tried an average of four previous drugs.
Two-thirds were given eribulin, and the others received whatever treatment their doctors wanted to try, since there is no standard of care in this situation.
Median survival was just over 13 months for those on eribulin versus less than 11 months for the others, said study leader Dr. Christopher Twelves, of St. James's Institute of Oncology in Leeds, England.
About half of women on eribulin had typical chemotherapy side effects - fatigue, low white blood cell counts, loss of hair, numbness and tingling in different parts of the body. About one-fourth of women in each group had serious side effects related to their treatments.
The study was sponsored by Japan-based Eisai Inc., which last week received a promise of quick review from the FDA. A company spokesman said no price has yet been set for the drug.
"There aren't many drugs that show a survival advantage in this setting," and the amount of benefit seen in this study gives eribulin "a reasonable chance" of being approved, said Dr. Eric Winer, breast cancer chief at the Dana-Farber Cancer Institute in Boston.
More than 1 million women worldwide are diagnosed with breast cancer each year. In the United States last year, there were an estimated 194,280 new cases and 40,610 deaths from the disease.
The studies were reported at the annual meeting of the American Society of Clinical Oncology.
Explore further: AstraZeneca cancer drug, companion test approved
More information: Cancer meeting: http://www.asco.org
National Cancer Institute: http://www.cancer.gov