Study Confirms That Raloxifene Reduces Risk of Invasive Breast Cancer in Postmenopausal Women

The drug raloxifene (Evista) significantly reducesthe risk of invasive breast cancer in postmenopausal women, according to the results of a large-scale study involving theUniversity of Pittsburgh Graduate School of Public Health (GSPH) and publishedin a recent issue of Breast Cancer Research and Treatment (65[2]:125-134, 2001).The Multiple Outcomes of Raloxifene Evaluation (MORE) trial measured the effectsof raloxifene, which has been approved by the US Food and Drug Administrationfor the prevention and treatment of osteoporosis, on breast cancer rates after 4years of follow-up. The results confirm the study’s preliminary findings,which where initially published in the Journal of The American MedicalAssociation (281:2189-2197, 1999).

"The MORE trial showed that raloxifene reduces the risk ofinvasive breast cancer by 72% in women who took this drug daily for 4years," said Jane Cauley, DrPH, lead author of the study report andassociate professor of epidemiology at the GSPH. "Specifically, raloxifenereduced the risk of estrogen-receptor-positive invasive breast cancer by 84%.This finding indicates that raloxifene is very effective at curbing thedevelopment of estrogen-fed breast tumors among older women with an averagebreast cancer risk."

MORE Results

MORE, a multicenter osteoporosis trial, involved 7,705postmenopausal women, with an average age of 66.5 years and a history ofosteoporosis. About 12% reported a family history of breast cancer. Participantswere randomly assigned to receive 60 or 120 mg of raloxifene per day or aplacebo. Neither investigators nor participants knew who received placebos andwho received raloxifene.

After 4 years, 39 cases of breast cancer were confirmed amongthe 5,129 women assigned to either dose of raloxifene, compared with 28 casesamong the 2,576 women assigned to the placebo. There were no significantdifferences in outcome between the group taking 60 mg of the drug and thosetaking 120 mg. Overall, raloxifene was well tolerated by participants.

Venous thromboembolism is a serious, although infrequentlyreported side effect of raloxifene. Other side effects associated withraloxifene include flu symptoms, hot flashes, leg cramps, endometrial cavityfluid and peripheral edema.

Longer-term effects of raloxifene on reducing the incidence ofbreast cancer in postmenopausal women will be evaluated in the ContinuingOutcomes Relevant to Evista (CORE) trial.