Taking the drug Study Finds That Tamoxifen Does Not Affect Cardiovascular Health (dateline January 3, 2001) | Breast Health News | Imaginis - The Women's Health & Wellness Resource Network

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Study Finds That Tamoxifen Does Not Affect Cardiovascular Health (dateline January 3, 2001)


Taking the drug tamoxifen (brand name, Nolvadex) to help prevent breast cancer does not increase the risk of cardiovascular problems such as heart attack in healthy women or in women with coronary heart disease, according to researchers. The study, which is the largest clinical trial to investigate the relationship between tamoxifen and cardiovascular risk, involved over 13,000 women at high risk of breast cancer.  According to the researchers, the findings should help comfort women who are taking tamoxifen to help prevent breast cancer.

The study was part of the National Surgical Adjuvant Breast and Bowel Project’s (NSABP) Breast Cancer Prevention Trial, which ran from 1992 to 1998. The NSABP found that post-menopausal women at high risk of breast cancer who took tamoxifen decreased their risk of developing invasive breast cancer by 49% compared to high risk women who took a placebo (inactive pill). The women were determined to be at high risk of breast cancer based on several factors, including family history and results of previous breast biopsies.

Now researchers have found that taking tamoxifen does not increase the risk for cardiovascular events, such as myocardial infarction (heart attack) or angina (chest pain caused by coronary heart disease). To reach this conclusion, researchers from the University of Pittsburgh School of Medicine were able to follow 13,194 women for four years after they finished taking tamoxifen. Of those women, 1,048 had a history of coronary heart disease (such as heart attack or angina) while the remaining 12,146 reported no cardiovascular problems.

The researchers found that the number of cardiovascular events were similar among the women who took tamoxifen and the women who took a placebo, regardless of their cardiovascular history. While there were more heart problems among the women with a history of coronary heart disease than among the healthy women, taking tamoxifen did not increase the risk of cardiovascular events.

"These findings should provide a degree of comfort to those women who are taking tamoxifen for breast cancer prevention," said Steven Reis, MD, associate professor of medicine at the University of Pittsburgh School of Medicine and lead investigator of the study, in a University of Pittsburgh Medical Center news release.

Results of the NSABP Breast Cancer Prevention Trial found the most common side effect of tamoxifen to be a higher occurrence of hot flashes. Other menopausal symptoms, such as vaginal dryness, were also reported. Tamoxifen also posed a slight increase in the risk of endometrial cancer (cancer of the uterine lining); approximately 2 out of 1000 women on tamoxifen develop endometrial cancer. Other potentially serious side effects of tamoxifen include blood clots in the veins of the legs (deep vein thrombosis), pulmonary embolism (blood clots in the lungs), and an increased risk of cataracts and stroke.

Tamoxifen is approved by the U.S. Food and Drug Administration (FDA) to help prevent breast cancer in post-menopausal women at high risk of breast cancer, and most women find that the benefit of reducing their breast cancer risk outweighs the risk of potential side effects of tamoxifen. However, all women who are considering tamoxifen should carefully discuss the advantages and disadvantages of the drug with their physicians. Tamoxifen is usually prescribed for a period up to five years to help prevent breast cancer. Tamoxifen is also used to help treat early and late stage breast cancer.

Women at high risk of breast cancer include:

  • Those with a strong family history breast cancer, especially among several first-degree relatives (mother or sisters)
  • Those whose previous breast biopsies show lobular carcinoma in situ (LCIS; also called lobular neoplasia) or atypical hyperplasia
  • Those who test positive for the BRCA1 (breast cancer gene 1) or BRCA2 (breast cancer gene 2) gene mutations

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