SAN ANTONIO – Adopting a standard exercise program resulted in a clinically meaningful 30% reduction in aromatase inhibitor-associated joint pain in breast cancer patients who participated in a year-long randomized trial.
The exercise prescription utilized in the HOPE (Hormones and Physical Exercise) trial was what’s recommended in national guidelines both for cancer survivors and healthy adults: 150 minutes per week of at least moderate-intensity aerobic activity, such as brisk walking, along with two strength-training sessions per week, Melinda L. Irwin, Ph.D., explained at the San Antonio Breast Cancer Symposium.
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The HOPE studies enrolled 121 postmenopausal women who had stage 1-3, hormone receptor–positive breast cancers and were physically inactive and overweight yet physically able to exercise. At enrollment, they were experiencing moderate aromatase inhibitor (AI)–associated joint pain, defined as a score of 5-7 on the 0-10 Brief Pain Inventory (BPI), after about 18 months on the medication. Roughly two-thirds of participants had no history of joint pain prior to starting AI therapy; the rest reported the AI exacerbated their preexisting joint pain. Subjects were randomized to the exercise program or to usual care, which included written information about the importance of exercise.
The primary study endpoint was the 12-month change in BPI worst pain score, which dropped by an average of 30% among the exercise group. This translated to an improvement in pain level from moderate at baseline to mild at follow-up. In addition, BPI scores rating pain severity and pain interference improved by about 20%. In contrast, patients in the usual care control group experienced a slight increase in BPI scores in all three domains over time, added Dr. Irwin, co-leader of the cancer prevention and control research program at Yale University Cancer Center, New Haven, Conn.
Dr. Melinda Irwin
This degree of improvement in joint pain is greater than reported in studies of glucosamine, acupuncture, or vitamin D supplementation, she noted.
The improvement in pain scores in the exercise group was greater at 12 months than at 3 or 6, suggesting that a year-long exercise program is probably necessary to see sustained reduction in joint pain.
At 12 months of follow-up, women in the exercise group averaged 159 minutes of physical activity per week, 110 minutes more than controls. Compliance with the supervised exercise program was notably good, with women attending an average of 70% of the twice-weekly small-group strength-training sessions.
In addition to the improvement in AI-related arthralgias, the exercise group experienced ancillary benefits: a mean 6.5% improvement in peak oxygen consumption, or VO2 max, compared with baseline, along with a 3% reduction in body weight.
HOPE was the first randomized trial to examine the effects of exercise on AI side effects in breast cancer patients. The impetus for the study was the recognition that arthralgias are the most common reason for poor adherence to and discontinuation of AI therapy. Up to 20% of breast cancer patients discontinue their AI within the first year. And both early discontinuation and poor adherence have been shown to be predictive of increased mortality risk.
The HOPE results received an enthusiastic audience reception. Physicians were particularly impressed with the 70% exercise adherence rate over the course of a year. They asked how they can keep their previously sedentary patients’ commitment to regular exercise from waning after an initial burst of enthusiasm, as so often happens.
Dr. Irwin replied that adherence to lifestyle change is always a challenge. Social support is quite helpful. The exercise group in HOPE received a paid gym membership and met in small groups with a personal trainer twice weekly.
"The women really bonded with each other. And there are now a growing number of free programs throughout the country, which give cancer survivors a start on an exercise program with a free gym membership for several months. For example, the Livestrong Foundation has partnered with the YMCA to offer free exercise programs for cancer survivors at local Ys," she said.
The HOPE trial was funded by the National Cancer Institute. Dr. Irwin reported having no financial conflicts of interest.