Open Access Research article

Joint pain severity predicts premature discontinuation of aromatase inhibitors in breast cancer survivors

Kannie Chim1, Sharon X Xie2, Carrie T Stricker3, Qing S Li1, Robert Gross2, John T Farrar2, Angela DeMichele234 and Jun J Mao123*

Author Affiliations

1 Department of Family Medicine and Community Health, University of Pennsylvania, 3400 Spruce Street - 2 Gates, Philadelphia, Pennsylvania 19104, USA

2 Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA

3 Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA

4 Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA

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BMC Cancer 2013, 13:401  doi:10.1186/1471-2407-13-401

Published: 3 September 2013

Abstract

Background

Premature discontinuation of aromatase inhibitors (AIs) in breast cancer survivors compromises treatment outcomes. We aimed to evaluate whether patient-reported joint pain predicts premature discontinuation of AIs.

Methods

We conducted a retrospective cohort study of postmenopausal women with breast cancer on AIs who had completed a survey about their symptom experience on AIs with specific measurements of joint pain. The primary outcome was premature discontinuation of AIs, defined as stopping the medication prior to the end of prescribed therapy. Multivariate Cox regression modeling was used to identify predictors of premature discontinuation.

Results

Among 437 patients who met eligibility criteria, 47 (11%) prematurely discontinued AIs an average of 29 months after initiation of therapy. In multivariate analyses, patient-reported worst joint pain score of 4 or greater on the Brief Pain Inventory (BPI) (Hazard Ratio [HR] 2.09, 95% Confidence Interval [CI] 1.14-3.80, P = 0.016) and prior use of tamoxifen (HR 2.01, 95% CI 1.09-3.70, P = 0.026) were significant predictors of premature discontinuation of AIs. The most common reason for premature discontinuation was joint pain (57%) followed by other therapy-related side effects (30%). While providers documented joint pain in charts for 82% of patients with clinically important pain, no quantitative pain assessments were noted, and only 43% provided any plan for pain evaluation or management.

Conclusion

Worst joint pain of 4 or greater on the BPI predicts premature discontinuation of AI therapy. Clinicians should monitor pain severity with quantitative assessments and provide timely management to promote optimal adherence to AIs.

Keywords:
Aromatase inhibitor; Joint pain; Adherence; Adverse effects; Musculoskeletal; Breast cancer; Pain diagnosis; Pain management; Survivorship