An article published in The Lancet Oncology reports that postmenopausal women with breast cancer who are on endocrine treatment are likely to experience arthralgia and arthritis (joint symptoms) if they previously have used hormone replacement therapy (HRT), received a hormone-receptor positive tumor diagnosis, undergone chemotherapy, received treatment with anastrozole versus tamoxifen, or been obese. Dr Ivana Sestak and Dr Jack Cuzick (Cancer Research UK, London, UK) and colleagues discuss their results in a retrospective exploratory analysis of patients enrolled in the Arimidex [anastrozole] Tamoxifen Alone or in Combination trial (ATAC).

In the ATAC trial, postmenopausal women with breast cancer were randomly assigned to anastrozole (an aromatase inhibitor) or tamoxifen. Sestak and colleagues set out to determine the importance of a range of risk factors for joint symptoms and whether the importance of these risk factors changed according to how these women were treated. The study sample consisted of 5,433 women who reported no joint symptoms at the beginning of the ATAC trial.

The researchers found that joint symptoms were reported by 777 of 1937 women (41.1%) who previously had used HRT and 1001 of 3496 women (28.6%) who had not used HRT. In addition:

  • Joint symptoms were reported by 1556 of 4596 (33.9%) with hormone-receptor-positive tumors and in 124 of 448 (27.7%) with hormone-receptor-negative tumors.
  • Joint symptoms were reported by 461 of 1176 (39.2%) who received previous chemotherapy and in 1317 of 4257 (30.9%) who have not.

Obesity as measured by body-mass index (BMI) also correlated positively with the onset of joint symptoms. About 37.2% with BMI greater than 30 kg/m², 31.3% with BMI between 25 and 30 kg/m², and 31.0% with BMI <25 kg/m² reported symptoms. The researchers also noticed a difference depending on which treatment a woman received. The percentage reporting joint symptoms in the anastrozole was 35.2% compared to 30.3% in the tamoxifen group.

Endocrine treatment reduces the concentration of estrogen in the body, and estrogen deficiency has been linked to joint symptoms in several different settings. Since the effects of the risk factors can accumulate, they need to be taken into account when aromatase inhibitors are being considered for women. “Awareness of risk factors for joint symptoms will help both clinicians and patients to anticipate and manage these symptoms and ensure optimum adherence to endocrine treatment,” conclude the authors.

Risk factors for joint symptoms in patients enrolled in the ATAC trial: a retrospective, exploratory analysis
Ivana Sestak, Jack Cuzick, Francisco Sapunar, Richard Eastell, John F Forbes, Angelo R Bianco, Aman U Buzdar, on behalf of the ATAC Trialists’ Group
The Lancet Oncology (2008).
DOI:10.1016/S1470-2045(08)70182-7
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Written by: Peter M Crosta