Research on a current hormone treatment for breast cancer has shed light on what is referred to as menopausal arthritis, a condition caused by lack of the female hormone that inflames the joints and causes muscle pain. Researchers at Boston University Clinical Epidemiology Unit and the University of California, San Francisco, have examined the evidence linking aromatase inhibitors, a breast cancer treatment, and estrogen-deprivation joint pain. The findings were published in the September 2005 issue of Arthritis & Rheumatism.
Aromatase inhibitors work by blocking the conversion of androgen precursors into estrogens, thus lowering estradiol levels in the blood and estrogen levels in peripheral tissues. As effective as this treatment is in reducing the rates of recurrence in patients with postmenopausal breast cancers, the joint and musculoskeletal pain it causes is enough to make some women stop treatment altogether.
In 3 separate trials that studied the hormonal effects of cancer treatments, women who experienced estrogen deprivation reported a higher incidence of joint and muscle pain than those who did not. In a National Cancer Institute of Canada study, 5187 postmenopausal women, who had completed a 5-year course of tamoxifen therapy for breast cancer, were followed for 5 years as they took either the aromatase inhibitor or a placebo. Joint pain was reported in 25% of the women taking the inhibitor, compared with 16% of those taking the placebo.