Validation of a proxy for estrogen receptor status in breast cancer patients using dispensing data

Srasuebkul, Preeyaporn, Dobbins, Timothy A., Pearson, Sallie-Anne, Elements of Cancer Care (EoCC) Investigators and Ward, Robyn L. (2014) Validation of a proxy for estrogen receptor status in breast cancer patients using dispensing data. Asia-Pacific Journal of Clinical Oncology, 10 2: E63-E68. doi:10.1111/ajco.12015


Author Srasuebkul, Preeyaporn
Dobbins, Timothy A.
Pearson, Sallie-Anne
Elements of Cancer Care (EoCC) Investigators
Ward, Robyn L.
Title Validation of a proxy for estrogen receptor status in breast cancer patients using dispensing data
Journal name Asia-Pacific Journal of Clinical Oncology   Check publisher's open access policy
ISSN 1743-7563
1743-7555
Publication date 2014-06
Year available 2012
Sub-type Article (original research)
DOI 10.1111/ajco.12015
Open Access Status
Volume 10
Issue 2
Start page E63
End page E68
Total pages 6
Place of publication West Sussex, United Kingdom
Publisher Wiley-Blackwell Publishing
Collection year 2015
Language eng
Formatted abstract
Aim: To assess the performance of a proxy for estrogen receptor (ER) status in breast cancer patients using dispensing data.

Methods: We derived our proxy using 167 patients. ER+ patients had evidence of at least one dispensing record for hormone therapy during the lookback period, irrespective of diagnosis date and ER- had no dispensing records for hormone therapy during the period. We validated the proxy against our gold standard, ER status from pathology reports or medical records. We assessed the proxy's performance using three lookback periods: 4.5 years, 2 years, 1 year.

Results: More than half of our cohort (62%) were >50 years, 54% had stage III/IV breast cancer at recruitment, (46%) were diagnosed with breast cancer in 2009 and 23% were diagnosed before 2006. Sensitivity and specificity were high for the 4.5 year lookback period (93%, 95% CI: 86-96%; and 95%: 83-99%), respectively) and remained high for the 2-year lookback period (91%: 84-95%; and 95%: 83-99%). Sensitivity decreased (83%: 75.2-89%) but specificity remained high (95%: 83-99%) using the 1-year lookback period and the period is long enough to allow sufficient time for hormone therapy to be dispensed.

Conclusion: Our proxy accurately infers ER status in studies of breast cancer treatment based on secondary health data. The proxy is most robust with a minimum lookback period of 2 years.
Keyword Australia
Breast cancer
Data linkage
Estrogen receptor
Validation studies
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Non HERDC
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Created: Mon, 16 Feb 2015, 11:55:15 EST by Ms Kate Rowe on behalf of Office of Deputy Vice-Chancellor (Research)