Fig. 2.

Adjusted proportion (with 95% confidence intervals) of endocrine therapy use within 12 months of diagnosis over time, Kaiser Permanente Breast Cancer Survivors Cohort, 2001-2016. This figure shows endocrine therapy initiation within 12 months of breast cancer diagnosis by year of diagnosis. Figure 2a includes all ages and Figure 2b includes women aged 55 and older. The lines represent the proportion of women who initiated any endocrine therapy (solid line), tamoxifen first (small dash line), aromatase inhibitors first (big dash line), and no endocrine therapy (medium dash line). Each line is adjusted for age at diagnosis (<45, 45-<55, 55-<65, 65-<75, 75+), stage (I,II,III), grade (well differentiated, moderately differentiated, poorly differentiated/undifferentiated), HR status (ER+/PR+, ER+/PR−, ER−/PR+), and study site (KP CO, NW and WA). Study sites contributed different calendar periods to the analysis: Kaiser Permanente (KP) Colorado (years of diagnosis 2001-2014), KP Northwest (years of diagnosis 2001-2008), and KP Washington (years of diagnosis 2001-2016)