Tamoxifen Without Chemo May Be Enough
Some Types of Breast Cancer May Not Require Chemotherapy
July 19, 2002 -- Chemotherapy may not be necessary for preventing some types of breast cancer from coming back in postmenopausal women. A new report shows treatment with the drug tamoxifen may be enough to prevent recurrence in these women, without the negative side effects that come with chemotherapy.
But other experts say it's still too soon to consider withholding chemotherapy from women who have already suffered from breast cancer once, despite the potential side effects of chemotherapy.
The study, published in the July 17 issue of the Journal of the National Cancer Institute, involved 1,669 postmenopausal women who had undergone surgery to remove breast cancers that had not spread to the surrounding lymph nodes. Researchers say about half the women who had surgery for breast cancer between 1992 and 1996 in the U.S. fall into this category.
For the other half of U.S. women with breast cancers that have spread to the lymph nodes, the standard therapy includes a short course of chemotherapy followed by treatment with tamoxifen.
Although previous studies have shown that tamoxifen is effective at preventing tumors from coming back in women who have a type of breast cancer that grows when exposed to estrogen (known as estrogen-receptor or ER positive), researchers say there has been little evidence that chemotherapy provides any additional benefit for these women.
To determine the impact of adding chemotherapy to tamoxifen use, the researchers randomly divided the women into two groups. One group received chemotherapy followed by tamoxifen and the other received tamoxifen alone for five years. The women were also divided according to whether or not they had ER-positive or ER-negative cancers.
Researchers found women with ER-negative breast cancer benefited from chemotherapy. Their cancer-free survival rate was 84% rather than 69%, and their overall survival rate was 89% rather than 81% with tamoxifen alone.
But women who had ER-positive breast cancers saw no additional survival benefits from the addition of chemotherapy to tamoxifen.
Study author Monica Castiglione-Gertsch, MD, of the International Breast Cancer Study Group, and colleagues say these findings show that one size does not fit all when it comes to treating women with breast cancer. Instead, they should be treated with a much more individualized post-surgery treatment plan that their estrogen receptor status into account.
In an editorial that accompanies the study, Antonio C. Wolff, MD, and Martin D. Abelofff, MD, of the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, say much more research is still needed on the effects of these types of breast cancer treatments in older women.
They say any treatment plan must take into account the effect on the woman's quality of life. But although this study found a modest decrease in the quality of life of those women who received chemotherapy, those findings do not justify withholding chemotherapy. Instead, the editorialists say researchers should strive to develop more targeted chemotherapy treatments that will produce fewer side effects.