Explaining variation in quality of breast cancer care and its impact: a nationwide population-based study from...

To assess and explain variation in quality of care in breast cancer patients and estimate its impact on disease outcome.

The Slovenian National Cancer Registry database and clinical records of 1053 women with unilateral primarily non-metastatic invasive breast cancer diagnosed in 2013 were reviewed in this retrospective analysis. Quality care was defined as care fully compliant with quality indicators (QI) defined by European Society of Breast Cancer Specialists (EUSOMA). Multivariate logistic regression was used to determine the predictors of receiving quality care. Differences in overall survival (OS) and event-free survival (EFS, relapse, or progression of disease or death considered an event) based on adherence to QI were analyzed using Kaplan-Meier method and Cox models.

Younger age, no comorbidities, and HER2-negative tumor were associated with increased odds ratios for receiving quality care, whereas tumor stage and type of hospital had no significant association. Median follow-up was 54.5 months. Not receiving quality care resulted in an increased risk of dying [hazard ratio (HR) 1.68; 95% confidence interval (CI) 1.06-2.66; p = 0.026]. Difference in EFS between two groups was significant after adjusting for case mix and type of hospital (HR 1.80; 95% CI 1.29-2.52; p = 0.001) but disappeared when type of treatment was added into the model (HR 1.30; 95% CI 0.89-1.90; p = 0.178).

Observed comorbidity and age bias in delivering quality breast cancer care could be medically justifiable, whereas observed deviations dependent on HER2 status are puzzling. Complete adherence of treatment to quality indicators resulted in better OS.