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
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 used to reduce recurrence risk in premenopausal women.
Hormonal therapy usually is prescribed for 5 years after surgery. Still, research published in December 2012 suggested that taking tamoxifen for 10 years instead of 5 years after surgery reduced the number of recurrences and improved overall survival. Many doctors wonder if the aromatase inhibitors may offer more benefits if taken for longer than 5 years.
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.
New research shows that women taking generic aromatase inhibitors are more likely to stick to their treatment plans compared to women taking brand-name aromatase inhibitors.
The study, “The change from brand-name to generic aromatase inhibitors and hormone therapy adherence for early stage breast cancer,” was presented on Dec. 12, 2013 at the 2013 San Antonio Breast Cancer Symposium by Dawn Hershman, M.D., M.S., assistant professor of medicine at the Columbia University Medical Center and director of the Clinical Breast Oncology Program at New York-Presbyterian Hospital. Dr. Hershman is a member of the Breastcancer.org Professional Advisory Board.
A generic drug has the same active ingredients as an original, brand-name drug, as well as the same dosage, risks, and benefits. The only thing that’s different is the name. Generic drugs usually cost much less than brand-name drugs. Generic versions of drugs come to the market when the patent has expired on the brand-name drug.
The researchers looked at prescription records from 13,522 women ages 51 and older who were prescribed hormonal therapy after being diagnosed with early-stage breast cancer. The records were from January 2007 to December 2011. The three aromatase inhibitors became available as generics in 2010.
Looking at the records, the researchers found that:
- 7,532 women never switched medicines
- 5,990 women switched medicines at least once
The average cost for a month of medicine was:
- $7.70 for tamoxifen
- $9 for a generic aromatase inhibitor
- $33 for a brand-name aromatase inhibitor
Before generic aromatase inhibitors were available:
- 45% of women started hormonal therapy by taking tamoxifen
- 55% started by taking a brand-name aromatase inhibitor
After generic aromatase inhibitors were available:
- 42.6% of women started hormonal therapy by taking tamoxifen
- 38.3% of women started by taking a generic aromatase inhibitor
- 19.1% started by taking a brand-name aromatase inhibitor
Comparing women who took brand-name aromatase inhibitors to women who took generics, the researchers found that women who were taking generics were much less likely to stop taking the medicines early. In other words, women who were taking generic aromatase inhibitors were more likely to finish the full hormonal therapy regimen prescribed for them.
The researchers also found that women were more likely to stop taking hormonal therapy as the monthly price went from under $10 to higher than $20.
The results of this study are very interesting, but this is only one study looking at 2 years of generic aromatase inhibitor prescription information. While more research is needed, it does seem to make sense that more women would stick to their hormonal therapy regimen if the cost were more affordable. Still, we also know that side effects can have a huge effect on whether a woman sticks to their hormonal therapy treatment plan.
If you’re a postmenopausal woman who’s been diagnosed with hormone-receptor-positive, early-stage breast cancer and will be taking an aromatase inhibitor after surgery and other treatments, it’s very important that you take the medicine for as long as it’s prescribed. Hormone-receptor-positive breast cancer can come back and hormonal therapy after surgery reduces that risk -- you must remember that.
There are many different reasons why people may not follow their treatment plan as they should, including financial issues, side effects, and depression. If the cost of hormonal therapy is a concern for you, there are organizations that can help, including the assistance programs of many pharmaceutical companies and the National Cancer Institute. For more information, visit the Breastcancer.org Staying on Track With Treatment pages.