Treating Breast Cancer with Tamoxifen May Also Protect the Heart (dateline February 25, 2005)
Researchers have long known that the drug tamoxifen (brand name, Nolvadex) can help treat or prevent breast cancer in some women. However, according to a new study, tamoxifen may also significantly reduce the risk of heart attack or heart stress symptoms such as angina (severe chest pain). Past studies have shown that tamoxifen may reduce LDL ("bad") cholesterol. According to the new study, published in the journal Cancer, heart benefits typically occur within two years of tamoxifen use and remain for the duration of treatment.
Tamoxifen has been prescribed to women for over two decades to help treat breast cancer. More recently, tamoxifen has been used as to treat early stage breast cancer after breast surgery (lumpectomy or mastectomy). Tamoxifen has been shown to help prevent the original breast cancer from returning after breast surgery while also hindering the development of new cancers in the opposite breast.
In late 1998, tamoxifen became the first drug to be approved by the U.S. Food and Drug Administration (FDA) to prevent breast cancer after research showed it reduced the chances of developing breast cancer by 50% in women at high risk.
Tamoxifen is an "anti-estrogen" and works by competing with estrogen to bind to estrogen receptors in breast cancer cells that are estrogen-sensitive. About 80% of breast cancer patients have estrogen-sensitive breast cancer. By blocking estrogen in the breast, tamoxifen helps slow the growth and reproduction of breast cancer cells.
To study whether tamoxifen can protect the heart in addition to treating or preventing breast cancer, Brian D. Bradbury, D.Sc., M.A. and his colleagues of Boston University's Schools of Medicine and Public Health reviewed over 3,000 medical records of breast cancer patients treated with tamoxifen and over 4,000 medical records of patients with other cancers (bladder, colorectal, or non-melanoma skin cancers) who had not treated with tamoxifen.
The study results showed that the women on tamoxifen were significantly less likely to develop symptomatic heart disease than those who did not receive tamoxifen. The protective effect began within two years of beginning tamoxifen treatment and remained for the duration of treatment (in the study, this duration was five years). Because tamoxifen slightly increases the risk of endometrial cancer and other conditions, most women are prescribed to take tamoxifen for a period of five years to help treat breast cancer.
While the results of this study show that tamoxifen may help protect the heart, tamoxifen is a breast cancer treatment and is not prescribed for cardiovascular disease. Thus, heart protection appears to be an added benefit of the treatment.
Tamoxifen is associated with a number of side effects, most of them temporary. These include hot flashes and other menopausal symptoms. Tamoxifen has also been linked to other potentially serious conditions, including endometrial cancer, serious blood clots, and stroke. While the benefits of treating breast cancer with tamoxifen typically outweigh the risks for most breast cancer patients, the decision to use tamoxifen should be made carefully by the physician and patient together, taking into account the patients individual medical situation.