In a recent analysis of updated
data from the National Health Interview Survey, Dr. Erika Walters and
colleagues report on the use of Tamoxifen and Raloxifene by US women (see report) 1,2. These two selective estrogen receptor modulators bind estrogen
receptors in breast tissue and reduce the action of estrogen on breast cells.
Randomized controlled trials show that these two drugs significantly reduce the
risk of developing invasive breast cancer 3,4. The magnitude of risk reduction is thus well established. In these
randomized trials a reduction in the order of 50% fewer breast cancers among
women taking the drug is seen for each of these agents. Comparing the two drugs
head to head showed a more favorable profile of side effects for Raloxifene
compared to Ramoxifene 5.
The FDA approved the use
of Tamoxifen for primary prevention of breast cancer in both premenopausal and
postmenopausal women at high risk. This approval was in 1998. In 2007, the FDA
approved Raloxifene for primary prevention of breast cancer among
postmenopausal women.
The National Health
Interview Survey data show that the use of these two drugs for primary
prevention is extremely low. Based on the interview data it is estimated that n
2010 only about 100,000 women are using these drugs specifically for breast
cancer prevention. Approximately 300,000 women are using Raloxifene for
prevention of osteoporosis.
In a previous analysis of
the US population projections we estimated that 8 million women ages 50 to 69,
are at sufficient risk to justify use of these agents for prevention of breast
cancer (see article). The reduction in breast cancer would exceed any excess side effects.
Among these 9 million women some 21,000 cases of breast cancer could be
prevented each year. See related post.
There are many barriers
slowing our progress from scientific understanding of the causes and prevention
of cancer to implementing what we know 6,7. This example highlights some of this delay. Randomized trials
published in 1998 and 2004 led to FDA approval for indications to use drugs to
prevent breast cancer. Now in 2013 we are still missing the opportunity to prevent
thousands of breast cancers. Other strategies like avoiding postmenopausal hormones
and increasing physical activity and weight loss can add to the reduction. All
theses strategies remain underutilized. Isn’t it time to use what we know to prevent
breast cancer?
Related posts
References cited
2. Waters
EA, McNeel TS, Stevens WM, Freedman AN. Use of tamoxifen and raloxifene for
breast cancer chemoprevention in 2010. Breast
Cancer Res Treat. Jul 2012;134(2):875-880.
3. Fisher
B, Costantino JP, Wickerham DL, et al. Tamoxifen for prevention of breast
cancer - report of the National Surgical Adjuvant Breast and Bowel Project P-1.
J Natl Cancer Inst. 1998;90:1371-1388.
4. Martino
S, Cauley JA, Barrett-Connor E, et al. Continuing outcomes relevant to Evista:
breast cancer incidence in postmenopausal osteoporotic women in a randomized
trial of raloxifene. J Natl Cancer Inst. Dec
1 2004;96(23):1751-1761.
5. Vogel
VG, Costantino JP, Wickerham DL, et al. Update of the National Surgical
Adjuvant Breast and Bowel Project Study of Tamoxifen and Raloxifene (STAR) P-2
Trial: Preventing breast cancer. Cancer
Prev Res (Phila). Jun 2010;3(6):696-706.
6. Colditz
G. Cancer culture: epidemics, human behavior, and the dubious search for new
risk factors. Am J Public Health. 2001;91:357-359.
7. Colditz
GA, Wolin KY, Gehlert S. Applying what we know to accelerate cancer prevention.
Sci Transl Med. Mar 28
2012;4(127):127rv124.
