Fewer Side Effects Found with Tamoxifen
A new study by a team of British researchers has concluded that the long-term use of tamoxifen does not affect a woman's emotional or sexual health. This runs contrary to some previous studies that have indicated the anti-breast cancer drug may indeed have such quality of life impacts.
Tamoxifen is a drug taken in pill form that interferes with the activity of estrogen, effectively countering that hormone's cancer-promoting effects. Tamoxifen has been used to treat both early and advanced stage breast cancers for more than 20 years.
Dr. Lesley Fallowfield of the University of Sussex and colleagues, writing in the Journal of Clinical Oncology, studied 488 healthy women over a five-year period. All were considered to be at high risk for developing breast cancer. Half of the women were given tamoxifen, while the others were given a sugar pill.
Over the study period, the researchers found no decrease in the frequency of sexual activity or sexual pleasure between the two groups. On the contrary, nearly 87% of the tamoxifen users reported that they were as sexually active as before, compared with 75% of the placebo group.
Interestingly, mood swings were found to be slightly more frequent in the placebo group. Also, energy levels were lower in the placebo group-41% reported lower energy levels, compared to 28% of the tamoxifen users.
The authors cautioned that their study did not distinguish between premenopausal and postmenopausal women, or between women who were using hormone replacement therapy-which has been shown to affect mood and sexual function.
Nonetheless, they wrote, "our results are encouraging in that general psychological and sexual functioning did not seem to be affected adversely by tamoxifen."
The above study was not the only good news being reported about tamoxifen in the past few weeks. A pair of independent studies found that tamoxifen might actually provide important cardiovascular benefits in addition to fighting cancer.
Dr. Mary Cushman of the University of Vermont and colleagues, writing in the journal Arteriosclerosis, Thrombosis, and Vascular Biology, reported that tamoxifen appears to reduce levels of specific inflammatory markers that are associated with cardiovascular disease.
Cushman's team gave 46 healthy women a daily dosage of tamoxifen for a six-month period and compared them with 54 women who were given a placebo. In the tamoxifen group, they found significant reductions in three known markers for heart disease: cholesterol (9% reduction), C-reactive protein (22% reduction) and fibrinogen (26% reduction).
They said their findings are extremely important for women who may be at increased risk for heart disease. "Differences in the effects of tamoxifen, raloxifene and estrogen on inflammation markers may prove to have clinical implications for the use of these agents in women at increased cardiovascular risk," they wrote.
In another study, published in the Journal of the National Cancer Institute, Dr. Steven Reis of the University of Pittsburgh Medical Center and colleagues reported that long-term treatment with tamoxifen does not appear to have any cardiovascular side-effects on the women taking the drug.
Using data from the National Surgical Adjuvant Breast and Bowel Project Breast Cancer Prevention Trial, the researchers followed 13,194 women for an average of 4 years and found no statistically significant difference in "cardiovascular events"-heart attacks, angina, etc.-between women taking tamoxifen and those taking a placebo.
The researchers concluded that tamoxifen was not associated with an increased risk of heart problems, even in women at high risk for heart disease.
An accompanying editorial by Dr. V. Craig Jordan of Northwestern University Medical School went further, suggesting that additional studies with larger sample sizes and longer follow-up may show that tamoxifen actually has somewhat of a cardiovascular protective effect over time.
But Reis' team was more cautious, noting that their data showed no significant trend toward either a beneficial or a negative effect. Nonetheless, the fact that no increased risk of heart damage was associated with long-term tamoxifen use was singularly important.
SOURCES:
Journal of Clinical Oncology, April 1, 2001; 19:1885-1892
Arteriosclerosis, Thrombosis, and Vascular Biology, February 2001; (21)
Journal of the National Cancer Institute, January 3, 2001; 93:2-3, 16-21
National Surgical Adjuvant Breast and Bowel Project (http://www.nsabp.pitt.edu)
[Table of Contents] [Archived Issues / Search] [The Breast Center]