Abstract 1534
Background
Adjuvant endocrine therapy (AET) is an important treatment for post-menopausal hormone receptor positive breast cancer. We used health administrative data to explore factors associated with AET adherence and survival.
Methods
We used health administrative databases to investigate adherence of post-menopausal women (aged ≥ 66 years) who started endocrine therapy from 2005-2010. Adherence was measured by medical possession ratio (MPR) and characterized as low (<40% MPR), intermediate (40-79% MPR) or high (≥80% MPR) over a five-year period. We investigated factors influencing AET adherence using a multinomial logistic regression model and the association with all-cause death (5-years after starting AET) using a multivariable cox-proportional hazards model.
Results
We identified 5,692 eligible patients with a median age of 73 years (IQR: 69-78), 67% received lumpectomy, 33% mastectomy, 26% adjuvant radiation, 13% adjuvant chemotherapy and 70% of patient originally started on an aromatase inhibitor versus tamoxifen. AET adherence was low in 13% (n = 749), intermediate in 13% (n = 733) and high in 74% (n = 4,210) of patients. Lower levels of adherence were observed among older patients [low vs. high adherence: odds ratio (OR)=1.03, 95% CI: 1.02-1.05 (per year); intermediate vs. high adherence: OR = 1.02, 95% CI: 1.01-1.04 (per year)]. High adherence was associated with use of adjuvant chemotherapy (low versus high adherence OR = 0.42 95% CI: 0.30-0.59) and short-term follow-up with a medical oncologist within 4 months of starting AET (low vs. high adherence OR = 0.83, 95% CI: 0.69-0.99). Unadjusted analysis showed an increased risk of death among patients with lower AET adherence [low vs. high adherence: hazard ratio (HR)=1.31, 95% CI: 1.12-1.53 and intermediate vs. high adherence: HR = 1.40, 95% CI: 1.21-1.62]. However, a significant association could no longer be detected after multivariable adjustment.
Conclusions
Non-adherence to endocrine therapy appears to be more common among older breast cancer patients. Short-term follow-up visit by a patient’s medical oncologist after starting AET may help to improve adherence. Developing strategies to optimize endocrine therapy adherence are warranted.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Academic Medical Association of South Western Ontario (AMOSO).
Disclosure
T. Vandenberg: Advisory / Consultancy: Novartis; Advisory / Consultancy: Roche. K. Pritchard: Advisory / Consultancy: Pfizer; Advisory / Consultancy: Roche; Advisory / Consultancy: Amgen; Advisory / Consultancy: Novartis; Advisory / Consultancy: Eisai; Advisory / Consultancy: Genomic Health; Advisory / Consultancy: Myriad Genetics. A. Louie: Advisory / Consultancy: AstraZeneca; Honoraria (self): Varian Medical Systems Inc. J. Raphael: Honoraria (self): Hoffmann La Roche. All other authors have declared no conflicts of interest.
Resources from the same session
3425 - Feasibility and impact of prospective DPYD screening in the Irish population
Presenter: Mohammed Zameer
Session: Poster Display session 2
Resources:
Abstract
1972 - Diet-derived metabolites and the risk of colorectal cancer: a nested case-control study in a population-based cohort, the Singapore Chinese Health Study
Presenter: Dawn Chong
Session: Poster Display session 2
Resources:
Abstract
4103 - Loss of subcutaneous adipose tissue during chemotherapy predicts reduced survival in patients with incurable colorectal cancer undergoing palliative therapy
Presenter: Erin Stella Sullivan
Session: Poster Display session 2
Resources:
Abstract
4309 - Obese and overweight is associated with better prognosis in metastatic colorectal cancer patients treated with bevacizumab.
Presenter: Bozena Cybulska-Stopa
Session: Poster Display session 2
Resources:
Abstract
3554 - Patient characteristics associated with poor performance status, ECOG 2-3, and effect on survival in 1086 Finnish metastatic colorectal cancers (mCRC) nationwide (prospective RAXO study)
Presenter: Pia Österlund
Session: Poster Display session 2
Resources:
Abstract
4572 - Discovery and Diagnosis of Metastatic Colorectal Cancer (mCRC) in the Real World: Final Results from a European Survey
Presenter: Iga Rawicka
Session: Poster Display session 2
Resources:
Abstract
4783 - Adherence to recommended intake of calcium and colorectal cancer risk in the HEXA study
Presenter: Jeeyoo Lee
Session: Poster Display session 2
Resources:
Abstract
5106 - Body size, sex and sidedness of incident colorectal cancer in a prospective Swedish cohort study
Presenter: Christina Siesing
Session: Poster Display session 2
Resources:
Abstract
3364 - Middle East & North Africa Registry to characterize RAS mutation status and tumor specifications in recently diagnosed patients with metastatic colorectal cancer (MORE-RAS Study)
Presenter: Mohamed Oukkal
Session: Poster Display session 2
Resources:
Abstract
3668 - Patient Demographics and Management Landscape of Metastatic Colorectal Cancer in the Third Line Setting: real-world data in an Australian Population
Presenter: Sandy Tun Min
Session: Poster Display session 2
Resources:
Abstract