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 commonly used to reduce recurrence risk in premenopausal women.
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 breast cancer surgery either don’t start taking the medicine or stop taking it early. In many cases, this is because of side effects.
If doctors can find a way to ease these side effects, more women might stick to their treatment plans.
A study has found that the antidepressant duloxetine (brand name: Cymbalta) can ease joint pain in women diagnosed with early-stage, hormone-receptor-positive breast cancer who are taking an aromatase inhibitor after surgery.
The research, “Randomized, placebo-controlled trial of duloxetine for aromatase inhibitor (AI)-associated musculoskeletal symptoms (AIMSS) in early stage breast cancer (SWOG S1202),” was presented on Dec. 9, 2016 at the 2016 San Antonio Breast Cancer Symposium.
The study included 255 women diagnosed with early-stage, hormone-receptor-positive breast cancer who had had surgery to remove the cancer. The women all had been taking an aromatase inhibitor for between 3 weeks and 3 months. All the women reported having moderate to severe joint pain since starting to take the aromatase inhibitor. The study took place between June 2013 and October 2015.
The women were randomly assigned to receive one of two treatments for joint pain:
- duloxetine: 30 mg daily for 7 days, then 60 mg daily for 11 weeks, then 30 mg daily for 7 days (127 women)
- placebo, a dummy pill that looked just like duloxetine and was taken on the same schedule (128 women)
The researchers assessed the women’s joint pain, depression, and quality of life 2 weeks, 6 weeks, and 12 weeks after starting duloxetine or placebo, and then again 24 weeks after the study started (11 weeks after completing duloxetine or placebo treatment).
The researchers found that at the 2-week, 6-week, and 12-week assessments, women in the duloxetine group had greater decreases in joint pain than women in the placebo group. By the 24-week assessment, joint pain reduction was the about the same for the two groups.
Women taking duloxetine also had improved quality of life compared to women taking the placebo.
While the side effects of hormonal therapy can be troubling, they’re overshadowed by the reality that hormone-receptor-positive breast cancer can come back. Hormonal therapy after surgery reduces that risk. If you’ve been prescribed hormonal therapy after surgery, you must remember this.
There are steps you can take to get rid of any obstacles stopping you from doing all you can to lower your recurrence risk. If side effects are a major problem for you, talk to your doctor about ways to manage them. You also may be able to switch to a different hormonal therapy.
If you’re currently taking an aromatase inhibitor and having joint pain, you may want to talk to your doctor about this study and ask if taking duloxetine is right for you and your unique situation.
Other studies have found that taking a fish oil supplement, acupuncture, massage, chiropractic therapy, and other complementary medicine techniques can help ease joint pain caused by aromatase inhibitors.
Before you start taking any supplement or try a complementary medicine technique, it’s a good idea to talk to your doctor and discuss all the risks and benefits of each supplement or technique. Together, you can develop a strategy to ease side effects and help you stick to your treatment plan.
For more information, visit the Breastcancer.org Bone and Joint Pain page in the Treatment Side Effects section.