CHICAGOThe selective estrogen-receptor modulator (SERM)
raloxifene (Evista) can dramatically reduce the incidence of breast
cancer in healthy postmenopausal women, V. Craig Jordan, PhD, DSc,
said at the San Antonio Breast Cancer Symposium. The agent is
currently FDA approved for the treatment of osteoporosis in
Dr. Jordan, director of the Lynn Sage Breast Cancer Research Program,
Northwestern University, presented integrated data from nine
multicenter, double-blind, placebo-controlled, randomized trials of
raloxifene in more than 10,000 women with no history of breast
cancer. The studies were conducted to show the drugs efficacy
in osteoporosis, and most of the women in these trials had osteoporosis.
The overview analysis with an average 40 months of follow-up showed
that raloxifene reduced the overall incidence of new breast cancers
by 54%. The incidence of invasive breast cancers was reduced by 64%,
and estrogen-receptor (ER)-positive tumors were decreased by 70%.
There was no decrease in ER-negative tumors.
The trials included 10,553 post-menopausal women aged 41 through 80
randomized to receive either placebo or raloxifene, 60 mg or 120 mg
daily. The data represent approximately 16,908 patient-years
cumulative exposure to raloxifene, and approximately 8,132
patient-years cumulative exposure to placebo.
The incidence rate of newly diagnosed breast cancers was 1.7 per
1,000 patient-years on raloxifene, compared with 3.7 per 1,000
patient-years on placebo (see Table).
This translates into a relative risk of breast cancer of 0.46 for
women receiving raloxifene, Dr. Jordan said, which corresponds to a
54% overall reduction in breast cancer incidence.