Breast Cancer Prevention Update?>

Breast Cancer Prevention Update

by Health After 50  

If you’re at increased risk for breast cancer, you should be aware of two recommendations recently updated by the U.S. Preventive Services Task Force (USPSTF), a federal panel of medical experts in preventive care, that may apply to you:

  1. You should consider being screened for the BRCA gene mutation, which increases the odds of developing breast and ovarian cancer if you have certain other risk factors.
  2. You should discuss with your doctor the option of taking risk-reducing drugs.

BRCA genes

Inheriting a BRCA1 or BRCA2 gene mutation increases your risk of breast, ovarian, fallopian tube, pancreatic, and peritoneal (the tissue lining the abdomen) cancer. Parents can pass BRCA gene mutations to their children. In August 2019, the USPSTF expanded its 2013 recommendation to encourage more women to consider being screened for the mutations. The new guideline was published in the August 20 issue of JAMA: The Journal of the American Medical Association.

The guideline advises doctors to assess BRCA mutation risk in women who have no symptoms and:

  • Have a personal or family history of breast, ovarian, fallopian tube, pancreatic, or peritoneal cancer
  • Have an ethnicity or ancestry associated with BRCA1 or 2 gene mutations, such as those of Ashkenazi Jewish descent

If either of these factors applies to you, your doctor will use a risk-assessment tool to further evaluate your likelihood of having a harmful BRCA mutation.

Other risk factors include:

  • A breast cancer diagnosis before age 50
  • Both a breast cancer diagnosis and an ovarian cancer diagnosis
  • A male relative with breast cancer
  • Multiple relatives with breast cancer
  • A relative who developed a BRCA-associated cancer in two sites, such as both breasts, or one breast and the ovaries

If you’re at high risk, your doctor will refer you to genetic counseling to help you decide whether to be tested for the mutation. If tests reveal a BRCA mutation, you and your doctor will discuss the best ways to lower your risk. Options include more frequent screenings, medication, or preventive surgical removal of the breasts or ovaries and fallopian tubes.

Harms of genetic testing include the chance of false-positive results (which erroneously suggest a mutation when none exists), worry or psychological stress before or after the outcome, and unnecessaryfollow-up testing or procedures. However, the USPSTF suggests that the benefits of risk assessment and referral to genetic counseling outweigh the harms.

Related: FDA Clears Home Test for Breast Cancer Gene

Risk-reducing medications

The second USPSTF recommendation, published in JAMA in September 2019, is an update of a 2013 guideline that advised women at increased breast cancer risk to discuss with their doctors the benefits and harms of a risk-reducing class of drugs called selective estrogen receptor modulators (SERMs), specifically tamoxifen and raloxifene. The revised guideline adds another class of drugs that women can choose from, called aromatase inhibitors, which include anastrozole and exemestane.

The recommendation is aimed at women ages 35 and older who have no symptoms but who have certain risk factors that increase their chances of breast cancer, including a family history of breast cancer and noncancerous abnormalities found on a prior breast biopsy.

About 80 percent of all cancerous breast tumors are stimulated by the hormone estrogen, which causes cancer to grow and spread. SERMs block the effects of estrogen by preventing it from binding to cell receptors in breast tissue. Aromatase inhibitors work differently: They stop other hormones from converting into estrogen.

While both classes of drugs reduce breast cancer risk, they can also increase the risk of serious adverse effects—which might partly explain why only about 16 percent of eligible women take the drugs, according to a review published in 2016 in the Annals of Oncology. Tamoxifen, and to a lesser extent raloxifene, increases the risk of dangerous blood clots that form in the legs and travel to the lungs, especially in older women. Tamoxifen also slightly to moderately increases the risk of endometrial cancer, and users have a greater risk of developing cataracts. Raloxifene confers neither of those risks, but tamoxifen is more effective in lowering breast cancer risk. Tamoxifen reduces risk by about 50 percent, and raloxifene by about 38 percent. Because of less serious side effects, raloxifene may be a better choice for some women.

Tamoxifen and raloxifene can also cause other side effects, such as hot flashes, vaginal dryness, and leg cramps. On the plus side, both drugs modestly reduce the risk of bone fractures in postmenopausal women. Aromatase inhibitors, however, are associated with a decrease in bone density.

Other side effects of aromatase inhibitors include hot flashes and other menopausal symptoms, diarrhea, muscle and joint pain, and elevated cholesterol. Aromatase inhibitors may be preferable over SERMs for women who have a high risk of developing blood clots. Both SERMs and aromatase inhibitors are taken daily for five to 10 years and have been shown to sustain their protective effect for more than five years after treatment is stopped.

Not all women with a high risk of breast cancer benefit from risk-reducing drugs. To decide whether you may benefit, your doctor will either use a risk-assessment tool or identify certain combinations of multiple risk factors that may increase your odds of developing cancer. The USPSTF says that women who are most likely to benefit from taking tamoxifen, raloxifene, or an aromatase inhibitor are those who have a 3 percent or higher likelihood of developing breast cancer in the next five years.

This article first appeared in UC Berkeley Health After 50.