The painful side effects of some breast cancer drugs lead many women to stop taking them, but results from a new study by Dr. Dawn Hershman, professor at Columbia University Irving Medical Center and Columbia University’s Mailman School of Public Health, and colleagues may help some women find relief and continue their treatment. The findings suggest that in some women, omega-3 supplements can significantly reduce severe joint pain caused by a commonly used class of breast cancer drugs. The results were presented at the American Society of Clinical Oncology annual meeting in Chicago.
[Photo: Dr. Dawn Hershman]
Drugs called aromatase inhibitors are commonly used to treat postmenopausal women with hormone receptor-positive breast cancer. These drugs, which are typically prescribed for 5 to 10 years, increase survival and reduce the chance of a cancer recurrence.
However, 45 to 60 percent of women taking aromatase inhibitors experience moderate to severe joint pain (arthralgia). Within two years, approximately 25 percent of women with arthralgia stop taking aromatase inhibitors due to this debilitating side effect. Another 25 percent cope by taking the medications intermittently, dampening their therapeutic effect. Arthralgia caused by aromatase inhibitors is more common in obese women, as excess weight can increase stress on the joints.
“We know that patients who have side effects from aromatase inhibitors are more likely to discontinue their treatment, which can raise their risk of a breast cancer recurrence,” says Dawn Hershman, MD, MS, a breast cancer specialist at NewYork-Presbyterian/CUIMC, professor of Epidemiology at the Mailman School of Public Health, and senior author of the study.“When we think of ways to control treatment side effects and improve adherence, it’s important to offer interventions that are acceptable to patients and are unlikely to introduce new side effects that could interfere with treatment.”
Studies have shown that taking omega-3 supplements can lead to decreased joint pain in patients with rheumatoid arthritis, an inflammatory disease. However, in breast cancer patients with aromatase inhibitor-related joint pain, previous data on omega-3 supplements has been mixed.
In an earlier multicenter clinical trial led by Hershman, about half of 249 breast cancer patients with moderate to severe joint pain were randomized to take omega-3 supplements for 6 months; the other half took a placebo. Although both groups reported a clinically meaningful decrease in joint pain, the placebo and omega-3s reduced pain by roughly the same amount.
“Since women with obesity tend to have more joint symptoms with aromatase inhibitors, we wanted to find out if this group of patients could also benefit more from omega3 supplements,” says Sherry Shen, MD, an Internal Medicine resident at NewYork-Presbyterian/CUIMC and the study’s lead author. “So we decided to reanalyze the data from the previous study to see if the effect of omega-3 fatty acids varied with body mass index.”
In the reanalysis, the researchers found that in obese women, omega-3 use was associated with an average decrease in pain of nearly 3 points (on a 1-to-10 pain scale), which was statistically different from the 1.5-point decrease associated with the placebo. No difference in pain relief was found between omega-3s and placebo among women with a BMI of less than 30.
The authors note that while these findings are preliminary and need to be confirmed with additional studies, they suggest that taking omega-3s could lead to improved adherence to aromatase inhibitor treatment in obese patients.
Hershman says that side effects of omega-3 supplements are generally mild; some women in the study reported reflux and a “fishy” taste, but overall, these supplements are very safe.
For women who are not obese and who are looking to reduce treatment-related joint pain, Hershman says research suggests that acupuncture and exercise may be helpful.
She and her colleagues are now analyzing the study participants’ blood samples to look for biochemical markers that may help physicians understand why certain patients may have more joint pain and identify the best treatment for each patient.
Dr. Hershman is also a professor of medicine in hematology/oncology at Columbia University Vagelos College of Physicians and Surgeons and an investigator with SWOG, a cancer clinical trials cooperative group supported by the National Cancer Institute.
The study, “Omega-3 fatty acid use for obese breast cancer patients with aromatase inhibitor-related arthralgia,”was funded by the NIH (5UG1CA189974), the Conquer Cancer Foundation, the Breast Cancer Research Foundation, and the Susan Komen Foundation.