Before deciding if you should take chemoprevention drugs, your health care provider needs to assess your breast cancer risk and may refer to you a high-risk program. The following risk factors put women at a higher-than-average risk for breast cancer:
• Aging
• Being a woman
• Being diagnosed with atypical ductal hyperplasia (ADH) or atypical lobular hyperplasia (ALH)
• Being diagnosed with a lobular carcinoma in situ (LCIS)
• Having relatives with breast cancer
• Having had invasive breast cancer or ductal carcinoma of situ (DCIS) previously
• Having a gene mutation linked to cancer that can run in the family, such as the BRCA gene mutation
The Breast Cancer Prevention Trial and the Study of Tamoxifen and Raloxifene are two major studies of chemoprevention drugs. These studies define “higher-than-average” risk of developing breast cancer to mean 1.7 percent risk during the next five years, according to the ACS.
Some organizations site this risk assessment as a benchmark for when to use the medications for women over age 35. Other organizations recommend using chemoprevention for women who are at least 35 with three percent or higher risk of developing breast cancer in the next five years.
Tamoxifen and Raloxifene are the only drugs approved in the U.S. to help reduce the risk of breast cancer. Both are pills taken once daily and need to be taken for five years.
In addition to being chemoprevention tools, both Tamoxifen and Raloxifene can help prevent osteoporosis, which is a severe weakening of the bones that is more common in women following menopause.
Taking chemoprevention drugs can benefit women by reducing their risk of developing breast cancer by more than a third. But, depending on the level of risk to start with, that might not be enough for some women to feel that the benefits outweigh the side effects.
The most common side effects of these drugs are menopause symptoms including:
• Hot flashes
• Irregular or stopped periods
• Night sweats
• Vaginal discharge
• Vaginal dryness
Some women – especially those who are close to menopause – will have their periods stop while on the drugs. Periods often don’t come back when the women stop taking the medication, according to the ACS. Instead, women go into menopause.
Both medications also carry risks for more serious side effects, though these risks are minimal. Tamoxifen and Raloxifene include the increased risk of developing blood clots in your leg or your lungs. The clots can cause serious problems and even death; however, the overall risk of these clots was less than one percent.
Tamoxifen carries a risk of causing uterine cancer, as well. The drug acts like estrogen and can increase the risk of both endometrial cancer and uterine sarcoma. It also is linked to increasing the risk of endometrial pre-cancers.
However, the overall risk of uterine cancer caused by Tamoxifen is low. One large study of women taking the drug for up to five years found that less than one percent of those women were diagnosed with uterine cancer.
According to the ACS, the risk of uterine cancer reduces back to normal within a few years after the women stop using Tamoxifen and Raloxifene. Generally, the benefit of these drugs often outweighs the possible risks for most patients.
Chemoprevention is not for everyone, but for those women with a higher-than-average risk of breast cancer, it is one tool that can be used in the fight against the disease. To learn more about your risk for breast cancer, talk to your doctor. For more information about high-risk breast cancer services, visit www.PremierHealth.com/highrisk.
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