Task force adds aromatase inhibitors to advice on breast cancer chemoprevention in high-risk women

By Reuters Staff

NEW YORK (Reuters Health) - 15/1/2019

In addition to tamoxifen and raloxifene, aromatase inhibitors (AIs) may now be considered for chemoprevention of breast cancer in women at high risk, the U.S. Preventive Services Task Force (USPSTF) said today in draft recommendations on the topic.

The updated recommendations are consistent with the 2013 USPSTF recommendations and just add aromatase inhibitors to the list of potential risk-reducing medications.

Specifically, the task force now recommends that doctors offer tamoxifen, raloxifene or aromatase inhibitors to women who are at increased risk for breast cancer and at low risk for adverse effects. This is a B recommendation.

"The USPSTF concludes with moderate certainty that there is a moderate net benefit from taking tamoxifen, raloxifene, or aromatase inhibitors to reduce risk of invasive breast cancer in women at increased risk," they write.

In a systematic review, they found that over five years, compared with placebo, tamoxifen reduced the incidence of invasive breast cancer by seven events per 1,000 women (95% confidence interval, 4 to 12), raloxifene reduced it by nine events (95% CI, 3 to 15) per 1,000 women, and aromatase inhibitors by 16 events (95% CI, 8 to 24) per 1,000 women.

For all three agents, these absolute benefits are likely higher for women with a predicted breast cancer risk of 3% or greater, the task force says.

The USPSTF says there is "convincing" evidence that tamoxifen and raloxifene are associated with small to moderate harms. Both increase risk for venous thromboembolic events; tamoxifen increases risk more than raloxifene and the potential for harms are greater in older women than in younger women.

There is "adequate" evidence that tamoxifen, but not raloxifene, increases the risk for endometrial cancer in women with a uterus. Tamoxifen also increases risk of cataracts. Vasomotor symptoms are common adverse effect of both medications.

As for aromatase inhibitors, the task force found "adequate" evidence that the harms of these agents are also small to moderate and include vasomotor symptoms, gastrointestinal symptoms, musculoskeletal pain, and possible cardiovascular events, such as stroke. Aromatase inhibitors do not reduce, and may even increase, the risk of fractures.

For women who are not at increased risk for breast cancer, the task force continues to recommend against the routine use of risk-reducing medications. This is a D recommendation.

"The USPSTF concludes with moderate certainty that the potential harms of taking tamoxifen, raloxifene, and aromatase inhibitors to reduce risk of breast cancer outweigh the potential benefits in women not at increased risk for the disease," they said.

These recommendations do not apply to women with a current or previous diagnosis of breast cancer or ductal carcinoma in situ (DCIS).

"Women who are at increased risk for breast cancer should be offered medications that can help reduce that risk," task force member Dr. Michael Barry from Massachusetts General Hospital and Harvard Medical School in Boston said in a news release.

"When deciding whether or not to offer medications, clinicians should carefully consider their patients' risk factors for breast cancer and balance these against the potential harms from the medications. These medications are not for everyone, and for women who are not at increased risk of breast cancer, the harms of these medications are likely to outweigh the benefits," added task force member Dr. Carol Mangione of the David Geffen School of Medicine at the University of California, Los Angeles.

The Task Force's draft recommendation statement and evidence review have been posted for public comment on the task force website http://bit.ly/2SVPoT3. Comments can be submitted until February 11.

SOURCE: http://bit.ly/2SVNPol and http://bit.ly/2SWIywD USPSTF 2019.

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