After surgery, women diagnosed with hormone-receptor-positive breast cancer usually take hormonal therapy medicine to reduce the risk of the cancer coming back (recurrence). Hormonal therapy medicines work in two ways:
- by lowering the amount of estrogen in the body
- by blocking the action of estrogen on breast cancer cells
A study suggests that compared to white women, black women are less likely to take hormonal therapy every day, as prescribed, and more likely to stop taking the medicine early.
The research was published online on Sept. 20, 2018, by the Journal of the National Cancer Institute. Read the abstract of “Endocrine Therapy Nonadherence and Discontinuation in Black and White Women.”
Hormonal therapy reduces recurrence risk
There are several types of hormonal therapy medicines. Tamoxifen, a selective estrogen receptor modulator (SERM), is one of the most well-known. Tamoxifen can be used to treat both premenopausal and postmenopausal women. In the early 2000s, the aromatase inhibitors:
- Arimidex (chemical name: anastrozole)
- Aromasin (chemical name: exemestane)
- Femara (chemical name: letrozole)
were shown to be 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. Aromatase inhibitors aren’t commonly used to reduce recurrence risk in premenopausal women.
Most women take hormonal therapy for 5 to 10 years after breast cancer surgery.
Still, like most cancer medicines, 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 are 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 surgery either don’t start taking the medicine or stop taking it early, in many cases because of side effects.
At the same time, 2017 statistics from the American Cancer Society show that black women are 42% more likely to die from breast cancer than white women.
So the suggestion that black women are not taking hormonal therapy as prescribed is especially troubling.
Black women report more side effects and treatment barriers
To do the study, the researchers used information from the Carolina Breast Cancer Study. The analysis included 1,280 women who had been diagnosed with stage I to stage III hormone-receptor-positive breast cancer and had been prescribed hormonal therapy. The women ranged in age from 20 to 74. Overall, 43.2% of the women identified themselves as black.
Two years after diagnosis, the researchers asked the women whether they were taking the hormonal therapy medicine as prescribed. The researchers noted how many women were not adhering to their hormonal therapy regimen, which they defined as:
- not taking hormonal therapy every day
- missing more than two pills in two weeks
- stopping hormonal therapy early, before the full course of medicine was completed
- skipping hormonal therapy completely
The researchers found that about 14% of black women reported not taking hormonal therapy as prescribed compared to about 5% of white women.
Compared to white women, black women also were more likely to report:
- hot flashes
- night sweats
- breast sensitivity
- joint pain
- forgetting to take hormonal therapy
- feeling that sticking to the hormonal therapy treatment plan was hard or very hard
- cost-related barriers to taking hormonal therapy
Compared to white women, black women also were more likely to believe that their risk of recurrence wouldn’t change if they stopped taking hormonal therapy.
Overall, younger women, women insured through Medicaid, and women earning less than $50,000 per year were more likely to not take hormonal therapy as prescribed.
"It's not women's fault that they're having a hard time with therapy. It's a hard medication to take," said Stephanie Wheeler, associate professor of health policy and management at the University of North Carolina, Chapel Hill, and lead author of the paper, in an interview with NPR. "I think we can do a better job supporting women.”
According to Wheeler, the study offers evidence that black women diagnosed with hormone-receptor-positive disease face unique barriers to completing a hormonal therapy treatment plan as prescribed, which may account for some of the differences in survival rates between the two groups of women.
"These data are important because they shed light on the modifiable mechanisms through which multifaceted and culturally competent behavioral interventions can help women with breast cancer achieve the best outcomes," she said.
If you’ve been diagnosed with hormone-receptor-positive breast cancer and will be taking hormonal therapy after surgery and other treatments, it’s very important that you take the medicine for as long as it’s prescribed and at the dose at which it is prescribed. Hormone-receptor-positive breast cancer can come back, and hormonal therapy after surgery reduces that risk -- you must remember that.
Side effects caused by hormonal therapy can be very troublesome for many women. It’s extremely important to talk to your doctor as soon as you start having any side effects, including hot flashes, joint pain, blood clots, trouble sleeping, fatigue, or difficulty concentrating. Don’t wait until the symptoms are intolerable and you have to stop taking the medicine. There are steps you can take to ease these side effects, including switching to a different type of hormonal therapy.
For more information, visit the Breastcancer.org pages on Staying on Track With Treatment. You can read about why it’s so important to stick to your treatment plan, as well as ways to manage side effects after radiation, chemotherapy, and hormonal therapy. If you’re taking hormonal therapy after surgery now, stick with it as prescribed. If you’re thinking of stopping early, talk to your doctor first. Together, you can find a solution that is best for you.
To talk with others about staying on track with hormonal therapy treatment, join the Breastcancer.org Discussion Board forum Hormonal Therapy - Before, During, and After.