PCN91 ARTHRALGIA AND PATIENT-REPORTED OUTCOMES IN POSTMENOPAUSAL WOMEN WITH EARLY BREAST CANCER TAKING AROMATASE INHIBITORS: LONGITUDINAL ANALYSES

560 Background: High body mass index (BMI) protects against postmenopausal osteoporotic fracture, mediated in part by higher endogenous levels of oestradiol. Third-generation aromatase inhibitors (AIs) show superior efficacy and tolerability than tamoxifen in the adjuvant treatment of postmenopausal women with hormone receptor-positive early breast cancer. We examined the interactions between BMI and bone turnover during treatment with 3 aromatase inhibitors in the LEAP trial, an open, randomized, pharmacodynamic study in postmenopausal women. Methods: Healthy volunteers from the UK and Hungary with normal bone density and BMI between 18 and 34 kg/m2 were randomized to receive A (1 mg/day), L (2.5 mg/day), or E (25 mg/day) orally, once daily for 24 weeks. Effects on bone resorption (log transformed serum C-telopeptide crosslinks, CTX) and bone formation (bone alkaline phosphatase and propeptide of type I procollagen, PINP) were compared. Changes in biochemical markers of bone resorption and formation during treatment were all statistically inter- correlated (p<0.01) with no notable differences between the 3 agents studied, so that the groups were pooled for analysis. Spearman correlation coefficients and the p-values were computed. Results: A total of 90 participants were evaluable at baseline and at 24 weeks (29 A, 29 L, 32 E). As expected, baseline BMI correlated with pre-treatment circulating endogenous oestradiol (r=0.28, p=0.007) and both BMI and oestradiol negatively correlated with baseline serum CTX (r=-0.32, p=0.0025 and r=-0.35, p=0.0007 respectively) and PINP (r=-0.30, p=0.004 and r=-0.26, p=0.016 respectively). Baseline BMI and oestradiol were significantly correlated with the increase in serum CTX (r=0.26, p=0.015 and r=0.23, p=0.032 respectively) and BMI also correlated significantly with the increase in serum PINP (r=0.23, p=0.030). Conclusions: Steroidal and non-steroidal AIs increase bone turnover with the greatest increase in women with high BMI and higher oestradiol levels at baseline. As increased bone turnover is an independent risk factor for fracture, a high BMI may not confer a reduced fracture risk in the setting of AI use in early breast cancer. No significant financial relationships to disclose.

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Changes in adjuvant endocrine therapy over one year among postmenopausal women with early-stage breast cancer initiating aromatase inhibitors.

Journal of Clinical Oncology ◽

10.1200/jco.2012.30.34_suppl.11 ◽

2012 ◽

Vol 30 (34_suppl) ◽

pp. 11-11

Author(s):

Danielle Lindsay LaMorte ◽

Katherine E. Hartmann ◽

Vandana Gupta Abramson ◽

Ingrid A. Mayer ◽

Nancy Walker Peacock ◽

...

Keyword(s):

Breast Cancer ◽

Postmenopausal Women ◽

Endocrine Therapy ◽

Aromatase Inhibitors ◽

Clinical Decision Making ◽

Early Stage ◽

Adjuvant Endocrine Therapy ◽

Early Stage Breast Cancer ◽

Patient Reported ◽

One Year

11 Background: Aromatase inhibitors (AIs) are standard of care for adjuvant endocrine therapy (AET) to prevent recurrence of early stage breast cancer in postmenopausal women. Previous AET adherence research has focused on the 25-96% adherence observed with, but more information is needed about AI adherence, especially regarding the role of arthralgia (joint pain or stiffness) in AET changes. Our objective was to understand AET changes within a year of AI initiation. Methods: We examined AET switching (either to another AI or to tamoxifen), overall changes in AET (including switching and temporary or permanent discontinuation), and physician- and patient-reported arthralgia, using data abstracted from medical records and self-administered surveys among 93 patients initiating AI. We conducted Chi-square and Wilcoxon univariate analyses. Results: Anastrazole was initially prescribed to 64 patients (69%), letrozole to 28 patients (30%), and exemestane to 1 patient. A year after AI initiation, 64 patients (69%) had no change in AET. Among the 29 patients (31%) who had an AET change, 14 switched to at least one other AI, 11 switched to tamoxifen, 9 temporarily discontinued AET, and 7 entirely discontinued AET (categories not mutually exclusive). Average time to first AET switch was 182.7 days. Average number of AET switches was 1.4. Arthralgia was the most common reason for AET changes, noted in the records of 19 patients (66% of those who changed AET). Patients who changed AET reported more severe arthralgia (median pain from 0-10 among 8 joint groups =1.4, interquartile range [IQR]=0.3-2.6) at week 12 than those who did not (median=0.3, IQR=0-1.1), p=0.03. A higher proportion (46%) of the 28 patients who initiated with letrozole changed AET due to arthralgia, compared with 20% of the 64 patients who initiated with anastrazole (p=0.01). Conclusions: A substantial proportion of women initiating AI change AET over one year. Arthralgia appears to play a key role in AET changes, particularly for letrozole as compared with anastrazole. More longitudinal patient-reported arthralgia data are needed to guide clinical decision making about AI initiation and AET changes.

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