Aromatase inhibitors such as Arimidex (anastrozole), Femara (letrozole), and Aromasin (exemestane) are used to treat estrogen receptor positive (ER+) breast cancer in postmenopausal women. These drugs are designed to inhibit the action of the enzyme aromatase, which converts androgens into estrogens. Women who complete their anti-estrogen treatments (including aromatase inhibitors and/or tamoxifen) tend to have better recurrence and survival outcomes than women who do not. However, these treatments can result in vasomotor (hot flashes, night sweats), genitourinary (vaginal dryness, frequent urinary tract infections, urinary incontinence, sexual dysfunction), and musculoskeletal (joint pain, fractures) side effects. Some women do not finish their treatments because of the severity of these secondary effects. Now a new trial has reported that a six-week home-based walking program improved aromatase inhibitor-associated joint pain.

Arthralgia (joint pain) is a common side effect of aromatase inhibitors. It is caused by estrogen deprivation, but can be exacerbated by local and systemic inflammation. There are few safe and effective long-term treatments for aromatase inhibitor-induced joint pain. Sometimes a switch in aromatase inhibitors can improve arthralgia and other side effects. Ginger, sour cherries, olive oil, pomegranate juice and fish oil all appear to improve arthralgia symptoms in some women without inducing estrogenic effects. However, the beneficial effects of individual dietary components tends to be subtle. In some women, nightshade vegetables such as tomatoes, potatoes and eggplant can exacerbate arthralgia.

Exercise appears to be the most effective remedy and has the added benefit of reducing risk of breast cancer recurrence. There appears to be a role for all three main types of exercise (aerobic, weight-bearing and stretching) in reducing the side effects of aromatase inhibitors. Exercise can also help maintain heart and brain health, reduce fatigue, and improve sleep quality.

Trial reports walking improves arthralgia symptoms

The study referenced above reported the results of a phase II trial designed to evaluate the impact of a six-week, home-based walking program on aromatase inhibitor-associated arthralgia. The trial included 62 breast cancer patients with stage 0-III disease, on aromatase inhibitor treatment for at least four weeks, exercising at most 150 minutes per week, and reporting at least level 3 joint pain intensity at its worst on a 5-point scale. Half of the study participants were randomly assigned to a self-directed Walking Intervention group; the remainder served as controls (designated the Wait List Control group). Participants had average age of 64, 74% were white, and 63% had a body mass index (BMI) of at least 30 (i.e., they were obese or morbidly obese). The Exercise and Control groups were compared at the six-week endpoint of the exercise intervention and six month later.

At the end of the six-week trial, participants in the Exercise group reported significantly increased number of walking minutes per week, reduced joint stiffness, reduced difficulty with daily living activities, and less perceived powerlessness in managing joint symptoms compared to the Control group. After six months, the number of walking minutes per week had declined significantly in the Exercise group. However, improvements in stiffness and difficulty with daily living activities were sustained. The authors conclude that the trial results indicate that exercise is a safe alternative or adjunct to medications for the management of aromatase inhibitor-associated arthralgia.