Femara Benefits Younger Women With Breast Cancer
Most Women May Not Need Additional Treatment
Oct. 17, 2005 (Denver) -- Most women with breast cancer do not need to take the breast cancer drug Femara after completing five years of standard tamoxifen treatment, researchers report.
In a new study, only the 30% of women with factors placing them at high risk of recurrence when they first started tamoxifen treatment would have benefited from taking Femara afterward, says researcher Gary Freedman, MD, a radiation oncologist at Fox Chase Cancer Center in Philadelphia.
Ever since a landmark study showed that Femara can reduce the risk of breast cancer coming back by about 40% in women previously treated with tamoxifen, "it's become common practice to automatically start women on Femara after completion of tamoxifen," he tells WebMD.
"But our analysis suggests it shouldn't be automatic. Treatment needs to be individualized." The study showed that women who were younger than 60 or whose cancer had spread to four or more lymph nodes at the time they started tamoxifen had the most to gain from Femara, he says. Both younger age and involvement of four or more lymph nodes are risk factors for recurrence; together they accounted for about three in 10 women studied.
On the flip side, women over age 60 and who have other health conditions should probably not be given the drug, he says.
The study showed that many of these women died from causes other than breast cancer in the 10 years after they first started taking tamoxifen, he says.
Richard Poetter, MD, a radiation oncologist at the University Clinic for Radiotherapy and Radiobology in Vienna, Austria, and a speaker at the cancer meeting, says the researchers raise "an intelligent hypothesis that should be tested further."
Given the side effects and cost of any treatment, "it's a good idea to try to figure out who will benefit most and who might not have as much to gain," he tells WebMD.
Side effects of Femara include muscle and bone pain, hot flashes, nausea, and headaches. More serious adverse reactions include blood clots, stroke, heart attack, and fractures.
But until the findings are confirmed, current evidence shows that doctors should discuss the risks and benefits of Femara and similar drugs, called aromatase inhibitors, with all eligible women who complete five years of tamoxifen therapy, Poetter says.
Femara Slashes Estrogen Levels
The study, presented here at the American Society for Therapeutic Radiology and Oncology 47th Annual Meeting, is the latest to point to a role of Femara in the treatment of postmenopausal women with breast cancer.
About three in five women with breast cancer have tumors that are fueled by estrogen, making hormone therapy a cornerstone of regimens to prevent recurrences and improve survival.
For 25 years, doctors have been using tamoxifen, which blocks estrogen from binding to cells and works against estrogen's ability to stimulate tumor growth and spread. So far, the benefits of tamoxifen have been shown to wane after five years of treatment, a major cause of concern, since one-third of cancers that recur come back between five and 10 years later.