The breast cancer drug tamoxifen may decrease women's risk of dying from lung cancer, according to a new study.

Women with breast cancer who took tamoxifen and also developed lung cancer were 87 percent less likely to die from their lung cancer than people in the general population with lung cancer , said study researcher Dr. Elisabetta Rapiti, of the Geneva Cancer Registry in Switzerland.

Tamoxifen works by blocking activity of estrogen, a hormone that has been linked to tumor growth, Rapiti said.

"It has not been clinically proven, but anti-estrogens like tamoxifen may act by reducing the proliferation of the tumor cells," Rapiti told MyHealthNewsDaily.

Because the finding was observational researchers looked at past health data, but didn't conduct their own clinical trial more studies need to be done before drawing a firm link between tamoxifen and lung cancer survival , she said.

The study was published online today (Jan. 24) in the journal Cancer.

Observations of survival

Rapiti and her colleagues looked at the medical histories of 6,655 women diagnosed with breast cancer between 1980 and 2003 who were included in the Geneva Cancer Registry. Of these women, 3,066 (46 percent) took anti-estrogen drugs .

Researchers found that 40 women also developed lung cancer these cases were evenly split between women who took anti-estrogen drugs and women who didn't.

However, among the women who took anti-estrogen drugs, there were 87 percent fewer deaths from lung cancer than would have been expected based on the death rate from that cancer among the general population, the study said. Among the women who didn't take anti-estrogen drugs, the death rate from lung cancer was 24 percent lower than expected.

The results remained the same even after researchers adjusted the results for smokers and nonsmokers, Rapiti said.

A broader view

This study provides knowledge for a growing field of research into using anti-estrogenic drugs used for cancer prevention, said Dr. Edward Kim, an associate professor of oncology at the University of Texas MD Anderson Cancer Center in Houston, who was not involved in the study.

The development of lung cancer has been increasing in women over the last few years, even in women who don't smoke, Kim said. Some researchers think that estrogen and other female hormones may drive certain cancers in women, and that by blocking estrogen, cancer development could be prevented, he said.

"It's an observation that others have also thought, but is now being observed in a large cohort of patients," Kim told MyHealthNewsDaily.

The observation that there might be a benefit to blocking estrogen to prevent lung cancer is not unreasonable, but it still needs to be tested and validated, he said.

"It raises a potential target in a specific population for possible prevention studies in the future," Kim said.

Pass it on: The breast cancer drug tamoxifen is linked with a decrease in deaths from lung cancer.

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