Results of the Study of Tamoxifen and Raloxifene (STAR) Released: Osteoporosis Drug Raloxifene Shown to be as Effective as Tamoxifen in Preventing Invasive Breast Cancer
Results* of the Study of Tamoxifen and Raloxifene, or STAR, show that
the drug raloxifene, currently used to prevent and treat osteoporosis in
postmenopausal women, works as well as tamoxifen in reducing breast cancer risk
for postmenopausal women at increased risk of the disease. In STAR, both drugs
reduced the risk of developing invasive breast cancer by about 50 percent. In
addition, within the study, women who were prospectively and randomly assigned
to take raloxifene daily, and who were followed for an average of about four
years, had 36 percent fewer uterine cancers and 29 percent fewer blood clots
than the women who were assigned to take tamoxifen. Uterine cancers, especially
endometrial cancers, are a rare but serious side effect of tamoxifen. Both
tamoxifen and raloxifene are known to increase a woman's risk of blood
STAR, one of the largest breast cancer prevention clinical trials ever
conducted, enrolled 19,747 postmenopausal women who were at increased risk of
the disease. Participants were randomly assigned to receive either 60 mg of
raloxifene (Evista®) or 20 mg of tamoxifen (Nolvadex®) daily for five years. The
trial is coordinated by the National Surgical Adjuvant Breast and Bowel Project
(NSABP), a network of cancer research professionals, and is sponsored by the
National Cancer Institute (NCI), part of the National Institutes of Health.
"This optimistic news from STAR is a significant step in breast cancer
prevention," said John E. Niederhuber, M.D., currently providing leadership at
NCI. "These results, once again, demonstrate the critical importance of clinical
trials in our efforts to establish evidence-based practices."
"In 1998, the landmark Breast Cancer Prevention Trial showed that tamoxifen
could reduce the risk of invasive breast cancer in premenopausal and
postmenopausal women by nearly 50 percent," said Norman Wolmark, M.D., NSABP
chairman. "Today, we can tell you that for postmenopausal women at increased
risk of breast cancer, raloxifene is just as effective, without some of the
serious side effects known to occur with tamoxifen."
Women taking either drug had equivalent numbers of strokes, heart attacks,
and bone fractures. Both raloxifene and tamoxifen are known to protect bone
health; it is estimated that half a million postmenopausal women are currently
taking raloxifene by prescription to prevent or treat osteoporosis.
Additionally, the initial results from STAR suggest that raloxifene does not
increase the risk of developing a cataract, as tamoxifen does.
"Although no drugs are without side effects, tamoxifen and raloxifene are
vital options for women who are at increased risk of breast cancer and want to
take action," said Leslie Ford, M.D., associate director for clinical research
in NCI's Division of Cancer Prevention. "For many women, raloxifene's benefits
will outweigh its risks in a way that tamoxifen's benefits do not."
The STAR researchers also tracked known menopausal side effects that occur
with both drugs and monitored the participants' quality of life. The data show
that side effects of both drugs were mild to moderate in severity, and quality
of life was the same for both drugs.
Participants in STAR are now receiving information about which drug they were
taking. Women assigned to raloxifene will continue to be provided with the drug
until they have completed five years of treatment. Those women assigned to
tamoxifen can choose to continue taking tamoxifen or to receive raloxifene to
complete their five years of treatment.
Study details include:
- STAR enrolled 19,747 women. This data analysis is based on the 19,471 women
for whom complete study information was available.
- The numbers of invasive breast cancers in both groups of women were
statistically equivalent. Among the 9,745 women in the raloxifene group, 167
developed invasive breast cancer, compared to 163 of 9,726 women in the
- More than half of the women who joined STAR had had a hysterectomy and,
therefore, were not at risk of uterine cancer. For those women with a uterus, 36
of 4,732 who were assigned to take tamoxifen developed uterine cancers (mainly
endometrial cancer) compared to 23 of 4,712 women who were assigned to take
- In STAR, women in the raloxifene group had 29 percent fewer deep vein
thromboses (blood clots in a major vein) and pulmonary embolisms (blood clots in
the lung) than women in the tamoxifen group. Specifically, 87 of 9,726 women in
the tamoxifen group had a deep vein thrombosis compared to 65 of 9,745 women
taking raloxifene. In addition, 54 of 9,726 women taking tamoxifen developed
pulmonary embolisms compared to 35 of 9,745 women taking raloxifene.
- The number of strokes occurring in both groups of women was statistically
equivalent: 53 of 9,726 women in the tamoxifen group and 51 of 9,745 women in
the raloxifene group had a stroke during the trial. There was no difference in
deaths from strokes: 6 of 9,726 women in the tamoxifen group and 4 of 9,745
women in the raloxifene group died from this event. Women at increased risk of
stroke (those with uncontrolled hypertension or uncontrolled diabetes, or a
history of stroke, transient ischemic attack, or atrial fibrillation) were not
eligible to participate in STAR.
- While tamoxifen has been shown to reduce, by half, the incidence of lobular
carcinoma in situ (LCIS) and ductal carcinoma in situ (DCIS), raloxifene did not
have an effect on these diagnoses. (LCIS and DCIS are sometimes called
noninvasive breast cancers.) Of the 9,726 women taking tamoxifen, 57 developed
LCIS or DCIS, compared to 81 of 9,745 taking raloxifene. This result confirms
data reported in 2004 in a large study of raloxifene, the Continued Outcomes
Relevant to Evista (or CORE Trial).
Women who participated in STAR were postmenopausal, at least 35 years old,
and had an increased risk of breast cancer as determined by their age, family
history of breast cancer, personal medical history, age at first menstrual
period, and age at first live birth. Before participating in the study, the
women were instructed about the potential risks and benefits of tamoxifen and
raloxifene and then were asked to sign an informed consent document.
STAR investigators presented additional data at the 42nd annual meeting of
the American Society for Clinical Oncology (ASCO) from June 2-6, 2006, in
Atlanta, Ga. "This is an important and long awaited trial," said Sandra J.
Horning, M.D., president of ASCO.
The maker of tamoxifen, AstraZeneca Pharmaceuticals, Wilmington, Del., and
the maker of raloxifene, Eli Lilly and Company, Indianapolis, Ind., provided
their drugs and matching placebos for the trial without charge to participants.
Eli Lilly and Company also gave NSABP support to defray recruitment costs at the
participating centers and to help local investigators conduct the study.
*Vogel VG; Costantino JP; et. al.; for the National Surgical Adjuvant Breast and Bowel Project (NSABP). Effects of Tamoxifen vs Raloxifene on the Risk of Developing Invasive Breast Cancer and Other Disease Outcomes: The NSABP Study of Tamoxifen and Raloxifene (STAR) P-2 Trial. JAMA. 2006;295:2727-2741. Published online June 5, 2006.
Land SR; Wickerham DL; et.al. Patient-Reported Symptoms and Quality of Life During Treatment With Tamoxifen or Raloxifene for Breast Cancer Prevention: The NSABP Study of Tamoxifen and Raloxifene (STAR) P-2 Trial. JAMA. 2006;295:2742-2751. Published online June 5, 2006.
For more information about STAR, including links to media materials and a
fact sheet, visit NCI's STAR home page at http://www.cancer.gov/star or at NSABP's
Web sites at http://www.nsabp.pitt.edu
For a Q&A related to the STAR results, go to: http://www.cancer.gov/newscenter/pressreleases/STARresultsQandA.
For B-roll related to the STAR results, go to www.thenewsmarket.com for digitized,
downloadable B-roll, or call the NCI Media Relations Branch at (301) 496-6641
for a Beta-tape copy.
For tools used to calculate a woman's risk of breast cancer, visit http://cancer.gov/bcrisktool or http://breastcancerprevention.com.
For a Spanish translation of the STAR results press release, go to:
For a Spanish translation of the STAR results Q&A, go to:
For a French translation of the STAR press release, go to:
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