New drug proves better than tamoxifen

BOSTON, Dec. 28 (UPI) -- A major international trial confirms that newer anti-cancer drugs can protect women against recurrence of breast cancer better than tamoxifen, considered the current gold standard, researchers said Wednesday.

Doctors working for the collaborative Breast International Group 1-98 trial recruited 8,010 women into the study that compared whether letrozole -- from a class of drugs known as aromatase inhibitors and sold by Novartis under the brand name Femara -- worked better than the standard of care, tamoxifen, in preventing cancer from returning in postmenopausal women who were treated for early-stage breast cancer.

"The five-year disease free survival estimates are 84 percent in the patients on letrozole and 81.4 percent of those women who were randomly assigned to receive tamoxifen," Aron Goldhirsch, professor of medical oncology at the University of Bern, Switzerland, told United Press International.

"The results of this study will change clinical practice," he said, because it confirms the usefulness of letrozole as a first-line treatment in postmenopausal women with early-stage breast cancer.

The study results will be published in Thursday's edition of the New England Journal of Medicine.

In the trial, 351 women taking letrozole had cancer recurrence compared with 428 women who were taking tamoxifen. That represented a 19-percent decrease in the relative risk of developing breast cancer if the women were taking Femara, said Goldhirsch, also director of the European Institute of Oncology in Milan, Italy.

He also noted that troubling side effects -- blood clots, endometrial cancer, vaginal bleeding and hot flashes -- occurred more often in the women who were taking tamoxifen.

On the other hand, more women on letrozole suffered bone fractures than those on tamoxifen, and more women on letrozole had adverse heart events.

While Goldhirsch said that concern about underlying osteoporosis might make a patient or clinician opt for tamoxifen as an adjuvant treatment following surgery, he said the cardiac problems mainly occurred in women who had underlying heart disease at the onset of the study.

"One thing that we did in this study that has not been done before," Goldhirsch said, "was to evaluate all the patients for cardiac problems before entering them in the study so we could see if there was any signal that either drug had a beneficial or hazardous impact on heart function. I am confident that there was no significant impact on the hearts of patients who did not have underlying disease at the time of therapy."

The study was sponsored and funded by Basel, Switzerland-based Novartis.

"This study confirms what has been happening in medical practice recently," said Gary Freedman, a member of the radiation oncology department at Fox Chase Cancer Center in Philadelphia.

Freedman told UPI that patients with underlying osteoporosis would probably be better off taking tamoxifen to prevent fractures than to take Femara for the low percentage of reduced risk of breast cancer.

In the study, 225 patients on Femara suffered fractures during the course of the study, compared with 159 patients on tamoxifen.

In an editorial in the Journal, Sandra Swain, professor of medicine at the Uniformed Services University of the Health Sciences in Bethesda, Md., said that further studies will further define where aromatase inhibitors will fit into treatment protocols.

"All the evidence points to aromatase inhibitors as critically important for improving the outcome among postmenopausal women with breast cancer and who are at a substantial risk for recurrent disease," Swain said.