Association of Modifiable Risk Factors With Early Discontinuation of Adjuvant Endocrine Therapy: A Post Hoc Analysis of a Randomized Clinical Trial

Abstract

Importance: Early discontinuation of adjuvant endocrine therapy (ET) is problematic among breast cancer survivors, with previous studies suggesting that up to 50% of women do not adhere to the recommended full 5 years of ET treatment.

Objective: To identify the association between early discontinuation of ET in the Trial Assigning Individualized Options for Treatment (TAILORx) and modifiable risk factors, polypharmacy, and types of additional medications such as antidepressants and opioids.

Design, setting, and participants: This post hoc analysis includes a subgroup of 954 patients with breast cancer in TAILORx, a randomized clinical trial conducted from April 7, 2006, to October 6, 2010. All participants received a diagnosis of hormone receptor-positive, ERBB2-negative, axillary node-negative breast cancer and started ET within a year of study entry. Analyses were conducted in the intent-to-treat population. Statistical analysis took place from January 15, 2020, to April 6, 2021.

Main outcomes and measures: Participants completed measures on cancer-related health-related quality of life including physical well-being and social well-being prior to initiating ET. Early discontinuation of ET was defined as discontinuation less than 4 years from initiation for reasons other than death or recurrence. Kaplan-Meier estimates were used to calculate discontinuation, and Cox proportional hazards regression joint prediction models were used to analyze the association between rates of adherence to ET with patient-level factors.

Results: A total of 954 women (mean [SD] age, 56.6 [8.9] years) were included in this analysis. In a joint model, receipt of chemoendocrine therapy (vs receipt of ET only; hazard ratio [HR], 0.57; 95% CI, 0.35-0.92; P = .02) and age older than 40 years (vs ≤40 years; HR for 41-50 years, 0.39; 95% CI, 0.18-0.85; P = .02; HR for 51-60 years, 0.28; 95% CI, 0.13-0.60; P = .001; HR for 61-70 years, 0.40; 95% CI, 0.18-0.86; P = .02; and HR for >70 years, 0.23; 95% CI, 0.07-0.77; P = .02) were associated with a lower probability of early discontinuation of ET. Adjusted for these factors, a history of depression compared with no history of depression (HR, 1.82; 95% CI, 1.19-2.77; P = .005), worse physical well-being compared with better physical well-being (HR, 2.12; 95% CI, 1.30-3.45; P = .002), and worse social well-being compared with better social well-being (HR, 1.94; 95% CI, 1.20-3.13; P = .006) were individually and significantly associated with a higher probability of early discontinuation of ET. Only antidepressant use at study baseline was associated with early discontinuation (HR, 1.87; 95% CI, 1.23-2.84; P = .003).

Conclusions and relevance: In this post hoc analysis of a randomized clinical trial, baseline patient-reported health-related quality of life components, such as poor social well-being, poor physical well-being, and comorbid depression, were significant risk factors for early discontinuation of endocrine therapies. These results support systematic screening for patient-reported outcomes and depressive symptoms to identify women at risk for discontinuation of ET.

Trial registration: ClinicalTrials.gov Identifier: NCT00310180.

Conflict of interest statement

Conflict of Interest Disclosures: Dr Yanez reported receiving grants from Northwestern University during the conduct of the study and consulting income from Blue Note Therapeutics outside the submitted work. Drs Gray, Sparano, and Gareen reported receiving grants from the National Cancer Institute during the conduct of the study. Dr Carlos reported receiving salary support as editor in chief of the Journal of the American College of Radiology; and travel support from the GE Radiology Research Academic Fellowship as board of review chair outside the submitted work. Dr Whelan reported receiving nonfinancial support from Genomic Health Inc outside the submitted work. Dr Sledge reported receiving grants from Eli Lilly during the conduct of the study; grants from Pfizer and Genentech; and personal fees from Verseau, Tessa Therapeutics, and Pionyr Inc outside the submitted work. Dr Cella reported receiving grants from the National Institutes of Health during the conduct of the study; and being president of FACIT.org. Dr Wagner reported receiving personal fees from Celgene Inc and Athenex Inc outside the submitted work. No other disclosures were reported.