MONDAY, Feb. 12 (HealthDay News) -- Postmenopausal breast cancer patients who switch from tamoxifen therapy to another type of drug, called an aromatase inhibitor, may gain a significant boost in survival, Italian research shows.

Women in the study made the switch two to three years into the typical five-year tamoxifen regimen, which is aimed at keeping recurrent breast cancer at bay.

According to the researchers, the improved performance of aromatase inhibitors means patients may also avoid the increased risk of death from other causes -- such as stroke or endometrial cancer -- that have been associated with tamoxifen.

"There's still a lot of questions that remain, but this study confirms that five years of tamoxifen alone is really becoming the wrong answer for most postmenopausal women," said Dr. Gary M. Freedman, a radiation oncologist at the Fox Chase Cancer Center in Philadelphia. "At this point, you have to say that aromatase inhibitors are in the mix of treatment at some point," said Freedman, who was not involved in the trial.

The study, led by Dr. Francesco Boccardo of the National Cancer Research Institute and University of Genoa, was expected to be published in the March 15 issue of Cancer.

Tamoxifen has been in widespread use among breast cancer survivors for the last two decades. The drug is typically taken after surgery, because it targets the hormone estrogen, which can promote tumor cell growth in women with estrogen-sensitive breast cancer. A standard five-year treatment of tamoxifen has been found to reduce breast cancer death rates by as much as 31 percent, Boccardo's team noted.

But aromatase inhibitors are a newer class of drugs. These medicines, which include Femara, Aromasin, and Arimidex, fight cancer cell growth in a different way by blocking the workings of an aromatase enzyme while also reducing estrogen.

But are these drugs better and safer than tamoxifen? To find out, Boccardo and his colleagues conducted two trials involving a total of 828 postmenopausal Italian breast cancer patients followed between 1992-2002.