Aromatase inhibitor-associated musculoskeletal symptoms: incidence and associated factors.

Purpose: Arthralgia is the most common side effect in breast cancer patients receiving aromatase inhibitor (AI) therapy. Few studies have evaluated the risk factors, onset, and incidence of musculoskeletal pain in these patients. This study identifies the risk factors of AI-related severe arthralgia and their prevalence.

Methods: All the clinical and pathological records of postmenopausal patients diagnosed with invasive breast cancer using AI at Samsung Medical Center from January 2005 to November 2007 were reviewed. Multivariate logistic regression analyses were performed to evaluate the risk factors of AI-associated musculoskeletal symptoms (AIMSS) and factors associated with AI discontinuance.

Results: Among 299 patients, 69 patients (23%) experienced musculoskeletal symptoms attributed to AI use. In multivariate logistic regression analysis, no statistically significant outcome was found to confirm the risk factors for the development of AIMSS. Among the 69 patients who experienced AI-associated musculoskeletal symptoms, 29 (39.7%) discontinued AI use. Multivariate logistic regression analyses revealed an association of prior tamoxifen use with discontinuance of AI (P < 0.01; odds ratio, 4.27; 95% confidence interval, 1.74 to 10.50).

Conclusion: Prior use of tamoxifen is related to discontinuation of AI due to AI-associated severe arthralgia. Special monitoring and proper pain control for these patients should be considered during the treatment period.