MONDAY, Jan. 24 (HealthDay News) -- The anti-estrogen drug that transformed the treatment of breast cancer three decades ago may also reduce the risk of dying from lung cancer, researchers say.

In a study published in the Jan. 24 online edition of the journal Cancer, tamoxifen lowered the risk of dying from lung cancer among women who already had breast cancer. However, the results are too preliminary to warrant giving tamoxifen to lung cancer patients.

"There aren't a whole lot of clinical implications, but it does provide more evidence to our accumulating knowledge that female sex hormones are involved in some way, shape or form in lung cancer progression," said Dr. Apar Kishor Ganti, assistant professor of oncology-hematology at the University of Nebraska Medical Center in Omaha. "Whether or not it's a cause is a little sketchy."

Ganti was not involved with the study.

Prior studies had indicated that taking hormone replacement therapy during menopause upped a woman's chances of dying from lung cancer.

So these researchers hypothesized that the opposite might be true -- that anti-estrogens might lower a woman's risk of death from lung cancer.

Previous studies have also indicated that lung cancers, like breast and gynecological cancers, express hormone receptors.

In the current study, Dr. Elisabetta Rapiti, from the Geneva Cancer Registry, and colleagues reviewed records of 6,655 women diagnosed with breast cancer in Switzerland between 1980 and 2003. Just under half (46 percent) received anti-estrogen therapy which, during that time period, was most likely tamoxifen (aromatase inhibitors were not yet in use in Switzerland, the authors stated).

Women taking anti-estrogen therapy had an 87 percent decreased risk of death from lung cancer, compared to women who weren't taking this type of therapy.

There was no link between anti-estrogen therapy and whether or not a woman actually developed lung cancer.

One limitation to the research, Ganti noted, is that only 40 women actually developed lung cancer, so it was a very small study group.

The estrogen receptors implicated in lung cancer "don't seem to discriminate between men and women," Ganti said, indicating that anti-estrogens might have the same effect in men, although it's too early to state this definitively.

Other than breast and gynecological cancers, such as ovarian cancers, lung cancer has been the most extensively studied with regard to its interplay with estrogen, said Jing Peng, a post-doctoral associate in the Cancer Prevention Program at Fox Chase Cancer Center in Philadelphia.

There is limited evidence that estrogen may play a role in head-and-neck cancers as well.

But the issue is a complicated one, with some studies in mice suggesting that tamoxifen might actually promote lung cancer, Peng said.

"This article at least verifies that further studies should be carried out," she said.

More information

The U.S. National Cancer Institute has more on lung cancer.