A new study was put forward where joint complaints recognized to aromatase inhibitors (AI), prevailing breast cancer drugs, are not connected to autoimmune or inflammatory disease. Researchers believe that women who were primarily concerned about the threat of arthritis should be encouraged to continue taking the medication. The findings of the study will be presented on Tuesday, November 9, at the 74th Annual Scientific Meeting of the American College of Rheumatology in Atlanta, Georgia.

For many post-menopausal women with breast cancer promoted by the hormone estrogen, AIs can dramatically reduce the risk of their cancer coming back. Doctors suggest that the AIs must be taken for five years to gain the full benefit; however the development of joint complaints in up to 35 percent of women forces many to stop early."It's not clear why these joint symptoms occur, but we wondered if they could be related to inflammation or an autoimmune disease," says Victoria K Shanmugam, MBBS, MRCP, assistant professor in the Division of Rheumatology, Immunology and Allergy at Georgetown University Medical Center, who led the study. "Our research ruled out both."

The case-controlled study included 25 postmenopausal breast cancer patients with hand pain and no known autoimmune disease that were treated for their cancer at Georgetown Lombardi Comprehensive Cancer Center. Another 23 participants who were not receiving the drugs enrolled as a control group.

"We did find 4 of 48 women with autoimmune disease – 2 in each group, that had previously been undiagnosed, but the frequency was similar both in women receiving AIs and those who were not receiving AIs," Shanmugam says. "We found that several patients in the control arm had a similar constellation of symptoms to those receiving AIs." However, Shanmugam and her team did not find any conclusive evidence from their tests of inflammatory arthritis in the women with breast cancer.

"Although our study helps to rule out inflammatory arthritis or autoimmune disease, we do not know why women using AIs have these musculoskeletal symptoms. Still, knowing that the drugs are not promoting inflammatory arthritis may be beneficial to a number of women," she concludes

"It would be prudent to refer those experiencing joint pain to a rheumatologist to rule out a previously undiagnosed autoimmune disease, and so that we can help address the symptoms," Shanmugam says. "Since the syndrome doesn't appear to be related to inflammatory arthritis, women should be encouraged to stay on their medication so they can gain the full benefit from it."