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Fertility Concerns May Make Young Women Skip or Delay Hormonal Therapy After Breast Cancer Surgery

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Younger women diagnosed with hormone-receptor-positive breast cancer may skip or delay taking hormonal therapy medicine after surgery because they’re concerned about having children, according to a study done by researchers at the Dana-Farber Cancer Institute.

The research was published on April 22, 2021, by the journal Cancer. Read the abstract of “Impact of fertility concerns on endocrine therapy decisions in young breast cancer survivors.”

About hormonal therapy
About the study
What this means for you

About hormonal therapy

After surgery, people diagnosed with hormone-receptor-positive breast cancer usually take hormonal therapy medicine to reduce the risk of recurrence (the cancer coming back). Hormonal therapy given after surgery is called adjuvant hormonal therapy.

Hormonal therapy medicines treat hormone-receptor-positive breast cancers in two ways:

  • by lowering the amount of estrogen in the body
  • by blocking the action of estrogen on breast cancer cells

Estrogen makes hormone-receptor-positive breast cancers grow. Reducing the amount of estrogen or blocking its action can decrease the risk of early-stage hormone-receptor-positive breast cancers recurring after surgery. Hormonal therapy medicines also can be used to help shrink or slow the growth of advanced-stage or metastatic hormone-receptor-positive breast cancers.

Hormonal therapy medicines are not effective against hormone-receptor-negative breast cancers.

There are several types of hormonal therapy medicines used to treat hormone-receptor-positive breast cancer:

  • aromatase inhibitors: Arimidex (chemical name: anastrozole), Aromasin (chemical name: exemestane), and Femara (chemical name: letrozole)
  • SERMs (selective estrogen receptor modulators): tamoxifen, Evista (chemical name: raloxifene), and Fareston (chemical name: toremifene)
  • ERD (estrogen receptor downregulator): Faslodex (chemical name: fulvestrant)

In most cases, you take hormonal therapy for 5 to 10 years after breast cancer surgery — usually tamoxifen or an aromatase inhibitor — depending on whether you’re premenopausal or postmenopausal.

Tamoxifen is effective at reducing recurrence risk in both premenopausal and postmenopausal women. Aromatase inhibitors are more effective at reducing recurrence risk in postmenopausal women and are now used more often than tamoxifen to treat women who’ve gone through menopause. Research also has shown that premenopausal women can take the aromatase inhibitor Aromasin as hormonal therapy as long as their ovarian function has been suppressed.

Both tamoxifen and aromatase inhibitors can damage developing embryos, so women taking hormonal therapy should not get pregnant and should use an effective non-hormonal type of birth control — such as condoms, a diaphragm along with spermicide, or a non-hormonal IUD — while they are taking hormonal therapy and for several months afterward.

Earlier studies suggest that women who are age 40 or younger when diagnosed with hormone-receptor-positive breast cancer are much less likely than older women to take hormonal therapy after surgery. One study found that younger women were 50% more likely to stop taking hormonal therapy and 40% more likely to skip doses — which doctors call being nonadherent to therapy — compared with women age 50 and older.

Both tamoxifen and aromatase inhibitors can cause side effects. Tamoxifen may cause hot flashes and increase the risk of blood clots and stroke. Aromatase inhibitors may cause muscle and joint aches and pains. Less common but more severe side effects of aromatase inhibitors include heart problems, osteoporosis, and broken bones. Research has shown that about 25% of women who are prescribed hormonal therapy to reduce the risk of recurrence after breast cancer surgery either don’t start taking the medicine or stop taking it early, often because of side effects.

The researchers who did this study wanted to know how concerns about fertility affected young women’s decisions about hormonal therapy after breast cancer surgery.

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About the study

The researchers used information from the Young Women’s Breast Cancer Study, which includes 1,302 women age 40 or younger diagnosed with any stage breast cancer between 2006 and 2016. The women completed a survey:

  • when they first joined the study
  • every 6 months for the first 3 years
  • every year after that

The surveys ask about:

  • sociodemographic information
  • medical history
  • current medicines
  • fertility concerns
  • hormonal therapy decision-making

This analysis included information from 643 women diagnosed with stage I to stage III hormone-receptor-positive breast cancer.

The characteristics of the women in the analysis were as follows:

  • half were older than 36 and half were younger
  • 86.2% were white and 13.8% were of other races/ethnicities
  • 40.9% were diagnosed with stage I disease
  • 43.9% were diagnosed with stage II disease
  • 15.2% were diagnosed with stage III disease
  • 78.9% were married or living with a partner
  • 36.1% had no children, 17.1% had one child, and 46.8% had two or more children before being diagnosed with breast cancer
  • 79.2% discussed fertility with their doctors before starting hormonal therapy

Researchers followed the women for 11.7 to 68.1 months.

The analysis found that within 2 years of being diagnosed with breast cancer, about 33% of the women said that fertility concerns affected their decisions about hormonal therapy. Of those women, 40% chose either not to start or to stop hormonal therapy.

Of the women who didn’t start or who stopped hormonal therapy, 66% reported at least one pregnancy or an attempt to get pregnant within 2 years of diagnosis.

Women who had children before being diagnosed with breast cancer were less likely to say that fertility concerns affected their hormonal therapy decisions compared with women who had no children before diagnosis.

“Our findings shed new light on the dilemma facing many young women with hormone receptor-positive breast cancer: whether to optimize adjuvant treatment or fulfill their desire for children in the near term,” Shoshana Rosenberg, ScD, MPH, assistant professor of medicine at Dana-Farber and the study’s senior author, said in a statement. “Physicians can best help their patients by understanding their goals and developing treatment strategies that incorporate their needs.”

The researchers also noted that the POSITIVE trial — which stands for Pregnancy Outcome and Safety of Interrupting Therapy for Women With Endocrine Responsive Breast Cancer — will help women and their doctors make the best decisions about both treatment and childbearing. This study is looking at whether premenopausal women who stop tamoxifen for a period of time to become pregnant and then resume tamoxifen after pregnancy get the same benefits as women who take tamoxifen continuously for 5 years.

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What this means for you

If you’re a younger woman who wants to have children after treatment for hormone-receptor-positive breast cancer, it’s very important to talk to your doctor about fertility preservation as you’re planning your treatment. You also can ask for a referral to a fertility specialist for counseling before treatment begins.

It’s also important to remember that hormone-receptor-positive breast cancer can come back. Hormonal therapy after surgery reduces that risk by almost 50%.

For more information on fertility preservation options, visit the Breastcancer.org pages on Fertility and Pregnancy Issues During and After Breast Cancer.

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Written by: Jamie DePolo, senior editor

Reviewed by: Brian Wojciechowski, M.D., medical adviser


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