The drug raloxifene (Evista) significantly reduces
the risk of invasive breast cancer in postmenopausal women, according to the results of a large-scale study involving the
University of Pittsburgh Graduate School of Public Health (GSPH) and published
in a recent issue of Breast Cancer Research and Treatment (65:125-134, 2001).
The Multiple Outcomes of Raloxifene Evaluation (MORE) trial measured the effects
of raloxifene, which has been approved by the US Food and Drug Administration
for the prevention and treatment of osteoporosis, on breast cancer rates after 4
years of follow-up. The results confirm the study’s preliminary findings,
which where initially published in the Journal of The American Medical
Association (281:2189-2197, 1999).
"The MORE trial showed that raloxifene reduces the risk of
invasive breast cancer by 72% in women who took this drug daily for 4
years," said Jane Cauley, DrPH, lead author of the study report and
associate professor of epidemiology at the GSPH. "Specifically, raloxifene
reduced the risk of estrogen-receptor-positive invasive breast cancer by 84%.
This finding indicates that raloxifene is very effective at curbing the
development of estrogen-fed breast tumors among older women with an average
breast cancer risk."
MORE, a multicenter osteoporosis trial, involved 7,705
postmenopausal women, with an average age of 66.5 years and a history of
osteoporosis. About 12% reported a family history of breast cancer. Participants
were randomly assigned to receive 60 or 120 mg of raloxifene per day or a
placebo. Neither investigators nor participants knew who received placebos and
who received raloxifene.
After 4 years, 39 cases of breast cancer were confirmed among
the 5,129 women assigned to either dose of raloxifene, compared with 28 cases
among the 2,576 women assigned to the placebo. There were no significant
differences in outcome between the group taking 60 mg of the drug and those
taking 120 mg. Overall, raloxifene was well tolerated by participants.
Venous thromboembolism is a serious, although infrequently
reported side effect of raloxifene. Other side effects associated with
raloxifene include flu symptoms, hot flashes, leg cramps, endometrial cavity
fluid and peripheral edema.
Longer-term effects of raloxifene on reducing the incidence of
breast cancer in postmenopausal women will be evaluated in the Continuing
Outcomes Relevant to Evista (CORE) trial.