Chemoprevention Helps Some Women Reduce Breast Cancer Risk

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Some women are at higher risk than others to develop title=breast cancer. For these women, there are types of preventive medications that can help reduce that risk. 

Chemoprevention is a term used for drugs that can potentially reduce the risk of breast cancer in women who are known to have a higher than average risk, according to the American Cancer SocietyOff Site Icon (ACS).

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, according to the ACS:

  • 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 Tamoxifen and Raloxifene. These studies define “higher-than-average” risk of developing breast cancer to mean 1.7 percent risk of developing breast cancer 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, according to the ACS. Other organizations recommend using chemoprevention for women who are at least 35 with 3 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, according to the ACS. 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, according to the ACS. 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, according to the ACS, 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 also include the increased risk of developing blood clots in your leg or your lungs. The clots can cause serious problems and even death, according to the ACS. However, the overall risk of these clots was less than 1 percent. 

Tamoxifen also carries a risk of causing uterine cancer. The drug acts like estrogen and can increase the risk of both endometrial cancer and uterine sarcoma, according to the ACS. It is also linked to increasing the risk of endometrial pre-cancers.

However, the overall risk of uterine cancer caused by Tamoxifen is low, according to the ACS. One large study of women taking the drug for up to five years found that less than 1 percent of those women were diagnosed with uterine cancer.

The risk of uterine cancer reduces back to normal after a few years of when women stop using Tamoxifen and Raloxifene, according to the ACS. However, the benefit of these drugs often outweighs the possible risks for most patients. 

Premier Physician Network’ (PPN) breast care services include care for benign (non-cancerous) and malignant (cancerous) breast conditions with procedures that include:

For more information about chemoprevention, talk with your doctor or visit Breast Care and Breast Surgery.

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