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LOS ANGELES—Now there are two
agents shown to prevent breast cancer.
Short—term use of raloxifene (Evista, Lilly) cut
new breast cancers by more than half among some
20,000 women in two big international trials, with
no apparent rise in endometrial tumors.
News of the selective estrogen receptor
modulator’s anticancer effects came just weeks
after NCI called an early halt to its trial of
tamoxifen (Nolvadex, Zeneca) when it posted a
45% reduction of breast cancer among 13,388
high-risk women.
The tamoxifen study was designed specifically to
look for cancer prevention, while the preliminary
raloxifene results emerged from safety databases in
trials for efficacy against osteoporosis, which is
raloxifene’s approved use.
In one raloxifene trial of 7,704 osteoporotic
women, a group led by Dr. Steven Cummings of
UCSF saw breast cancer drop by 74% after nearly
21/2 years of follow-up among women randomized
to active drug compared with those taking placebo.
Dr. Craig Jordan of Chicago’s Lurie Cancer Center,
whose team followed 12,000 postmenopausal
women, found a breast cancer decrease of 58%,
also after about 21/2 years.
Both trials, reported to the American Society of
Clinical Oncology meeting here, randomized two
women to different raloxifene doses for every one
given placebo. Breast cancer effects were seen at
both dosages, and both estrogen receptor-positive
and progesterone receptor-positive tumors were
significantly reduced.
Tamoxifen doubled the endometrial-cancer rate in
the NCI trial, but women taking 60 or 120 mg/day
of raloxifene in Dr. Cummings’ study had fewer
such tumors than controls did.
The raloxifene researchers continue to follow their
cohorts for longer-term effects, but NCI is urging a
direct comparison of the drugs. —Judy Ismach
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MZ
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