November 8, 2010

Popular Breast Cancer Drug Linked To Joint Pain

(Ivanhoe Newswire) -- A recent study suggests joint complaints attributed to aromatase inhibitors (AI) "“ standard breast cancer drugs "“ are not associated with inflammatory arthritis or autoimmune disease.  Researchers say because of that, women who were predominantly concerned about the risk of arthritis should be encouraged to continue taking the medication.

AI's can significantly reduce the risk of recurrence in post-menopausal women with breast cancer promoted by the hormone estrogen.  Doctors report that AI's must be taken for five years to gain the full benefit, conversely, the growth of joint complaints in up to 35 percent of women forces them to discontinue their treatment early on.

"It's not clear why these joint symptoms occur, but we wondered if they could be related to inflammation or an autoimmune disease," which Victoria K. Shanmugam, MBBS, MRCP, assistant professor in the Division of Rheumatology, Immunology and Allergy at Georgetown University Medical Center, who led the study was quoted as saying.  "Our research ruled out both."

The case-controlled study included 25 postmenopausal breast cancer patients with hand pain along with no known autoimmune disease whose cancer was treated at Georgetown Lombardi Comprehensive Cancer Center.  An additional 23 participants "“ not receiving the drugs "“ enrolled as a control group.

Subjects were evaluated after abstaining from non-steroidal anti-inflammatory drugs for 48 hours.  Signs of inflammation from arthritis would resurface in that time frame, the researchers reasoned.  They completed a health evaluation questionnaire.  The rheumatologist completed a history and physical, and disease activity score.  A variety of blood tests were conducted with x-rays and ultrasounds of all participants' hands being performed.

The rheumatologist and radiologist did not know which participants were taking AI's and which were not.

"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 AI's 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 AI's."

But 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 AI's have these musculoskeletal symptoms.  Still, knowing that the drugs are not promoting inflammatory arthritis may be beneficial to a number of women," she adds.

"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 concludes.  "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."

SOURCE: 74th Annual Scientific Meeting of the American College of Rheumatology