That's according to a Scottish study published today in the journal Clinical Cancer Research.
The researchers included John Smyth, MD, FRCP, a professor of medical oncology at the University of Edinburgh.
"This is an important landmark in the research and treatment of ovarian cancer," Smyth says in a University of Edinburgh news release.
"Despite intense scientific research over the past 20 years, there have been few new leads in our understanding of how this disease operates. But this study suggests that the addition of hormone therapy to our treatment strategy could extend and improve the lives of women with ovarian cancer," says Smyth.
In the U.S., ovarian cancer causes more cancer deaths than any other female reproductive system cancer. The American Cancer Society predicts that there will be about 22,430 new cases of ovarian cancer and about 15,280 deaths from ovarian cancer in the U.S. this year.
Ovarian Cancer Study
The Scottish study included 42 women with recurrent, estrogen-sensitive ovarian cancer.
The patients took a drug called Femara, which is an aromatase inhibitor, a type of drug that curbs estrogen production.
Smyth and colleagues monitored the women's blood level of a tumor marker called CA-125, a substance found in higher concentrations in ovarian cancer than in other cells. The blood test is used to monitor patients with a known cancer.
Eleven of the 42 patients (26%) showed no tumor growth over six months, based on their CA-125 levels.
The women whose tumors were most highly sensitive to estrogen were the most likely to respond to Femara treatment.
The researchers write that while more studies are needed, they believe that Femara might be most helpful when given early in treatment for estrogen-sensitive ovarian cancer, such as immediately after chemotherapy.
"Ovarian cancer can be a devastating disease, so this new discovery is particularly exciting," says Simon Langdon, PhD, in the University of Edinburgh news release.
Langdon, who worked on the study, is Honorary Senior Lecturer at the Edinburgh Cancer Research Centre at the University of Edinburgh.
"We still have a lot to do, but this research has furthered our understanding of the hormone control of ovarian cancer, which could provide less grueling treatments for cancer patients. It presents new possibilities for tailor-made cancer therapy and demands further investigation," says Langdon.
The study -- which was partly funded by Novartis, Femara's maker -- didn't test other hormonal treatments for ovarian cancer.
"The aim of this study was not to show that [Femara] was superior to other hormonal agents in the treatment of ovarian cancer, but that pre-selection of patients according to estrogen-receptor status results in a significant percentage of patients benefiting from anti-estrogen therapy," write the researchers.