Photo Courtesy © SABCS/Todd Buchanan 2013Melinda L. Irwin, PhD, MPH
A new study reported at the 2013 San Antonio Breast Cancer Symposium shows that a prescribed exercise program reduces joint pain in breast cancer survivors taking aromatase inhibitors (AIs), with pain reductions observed at all levels of exercise. These findings have the potential to improve adherence to AIs, which would in turn reduce the number of breast cancer recurrences. Abstract S3-03
“AIs play an important role in the effective treatment of HR-postive breast cancer. Unfortunately, many women discontinue the drug because of unpleasant side effects. In this study, we discover that exercise improves joint pain, the most common side effect of AI use. These results are a promising first step in developing clinical interventions that can improve AI-associated joint pain, and in turn, improve AI adherence, breast cancer survival, and quality of life,” stated lead author Melinda L. Irwin, PhD, MPH, associate professor of chronic disease epidemiology at the Yale School of Public Health and co-leader of the Cancer Prevention and Control Research Program at the Yale Cancer Center in New Haven, Connecticut.
Current NCCN recommendations call for 5 years of treatment with an AI after surgery or other primary treatment for postmenopausal women with stage I–III HR-positive breast cancer, accounting for nearly 70% of all newly diagnosed cases of breast cancer. Up to 50% of patients who take AIs, however, report arthralgias or joint pain and stiffness.
Irwin and colleagues conducted the 12-month Hormones and Physical Exercise (HOPE) study to compare the impact of an exercise program versus usual care on 121 breast cancer survivors who were taking AIs for at least 1.5 years and reported at least moderate joint pain. The women had stage I and II breast cancer and were sedentary but able to exercise, she said.
Study participants were randomized in a 1:1 ratio to a yearlong exercise program (twice-weekly supervised resistance and strength training sessions plus 150 minutes per week of at least moderate-intensity aerobic exercise such as brisk walking) or usual care (including education about the benefits of exercise).
This exercise program is recommended for healthy adults as well as cancer survivors by the American Cancer Society and other organizations. Participants in the experimental arm were provided free gym memberships.
At the end of 1 year, arthralgias (worst pain, pain severity, and pain interference) were reduced down to mild pain levels by 30% as a result of participation in the yearlong exercise program, compared with modest increases or no change in joint pain among participants assigned to usual care.
Improvements with exercise were seen across the board regardless of age, disease stage, cancer treatment (chemotherapy, radiation, or both), and duration of AI treatment.
A dose-response effect was also seen, with participants who attended at least 80% of the supervised exercise sessions having a 25% decrease in worst pain scores, whereas women who attended fewer than 80% of the supervised sessions having a 14% decrease.
Cardiorespiratory fitness also correlated with pain reduction, Irwin noted. Women who experienced a 5% increase in cardiorespiratory fitness had a 29% decrease in worst pain scores compared with a 7% decrease in worst pain scores among women who did not reach that benchmark.
The next group of studies will assess mechanisms that may be influencing the effect of exercise on AI-associated joint pain, such as body weight, inflammation, and muscular strength, as well as the time of onset of pain improvement with exercise.
It is not surprising that once again we find evidence of the benefits and importance of regular exercise. The HOPE study, which evaluated 121 women with hormone-receptor positive breast cancer who were taking aromatase inhibitors, found that exercise can help reduce and relieve up to 50% of joint pain among women who take the medically recommended medication.
The primary reason that women stop taking the treatment is due to the joint stiffness and pain. I have had many women over the past years tell me that they felt their quality of life was reduced due to the joint pain they suffered while taking the aromatase inhibitors. For women who already had a diagnosis of arthritis or joint issues prior to the use of an AI, the pain would often be debilitating.
One patient I worked with who already had arthritis issues and had tried aromatase inhibitor medication changes, ended up stopping the treatment due to the increased pain, which also led to a decrease in her activity level. Then she became depressed because of guilt. Her family told her that she should have continued taking this medication, despite her discomfort, because if her cancer returned it would be her fault for not taking the medication.
Being able to identify women who may have trouble tolerating these medications and providing additional information on side effect treatment will help decrease some of the nonadherence issues. Although the prior attempts of relieving or reducing joint pain with acupuncture, glucosamine, and vitamin D have been somewhat helpful, they obviously have not been effective enough if we still have as many as 20% of patients stopping treatment after the first year. This study provided helpful information, but we need to continue research into promoting adherence among women who need to take this treatment for the best outcome.