Background: A cyclin-dependent kinase inhibitor (CDK 4/6i) plus endocrine therapy (ET) is considered standard of care first-line (1L) treatment for patients with hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2-) MBC without visceral crisis. A recent retrospective claims analysis showed that the combination of ET-CDK 4/6i was underutilized at our institution as 1L therapy; notably that no patients over age 66 received the combination in 2018. We sought to confirm this finding using clinical real-world data (RWD). Methods: Records from patients with HR+ HER2- MBC treated in the 1L setting at our institution between 2017 and 2019 were abstracted by COTA and identified using COTA Real-world Analytics (RWA), an analytics platform enabling rapid investigation of longitudinal RWD. A subsequent confirmatory IRB-approved retrospective chart review was conducted. We excluded patients who initiated treatment at an outside facility, were seen only in the inpatient setting, or where treatment was not initiated by a medical oncologist at our institution. The treatment groups were divided into four cohorts: ET-CDK 4/6i, ET alone, chemotherapy, and no therapy. Descriptive statistics were used to describe 1L treatments and associated variables. Results: 135 patients with HR+ HER2- MBC were included. Median age was 62.2 y (30-99 y). The most common treatments were ET-CDK 4/6i (55%), chemotherapy (21%), and ET (17%). Seven percent of patients did not receive any treatment (patient refusal, hospice, or death). Rationale for chemotherapy included visceral crisis (34%), oligometastatic disease with chemotherapy administered as curative intent (24%), and low estrogen receptor expression (14%). Of the patients that received chemotherapy, 76% had visceral metastasis. There was an increase in the number of patients that received ET-CDK 4/6i from 45% in 2017 to 62% in 2019 (Figure 1). In patients age over 66 years, approximately 62% of patients received ET-CDK4/6i. Conclusions: Our study showed an increase in the utilization of CDK 4/6i at our institution from 2017-2019 at rates similar to national trends. This finding is significantly different from what was observed in a previous claims analysis. Our findings demonstrate the value of clinical RWD in understanding real-world treatment patterns. Future research will further leverage RWD to investigate deep clinical questions including treatment response, sequencing and patient outcomes.
First-Line Treatment by Category
Citation: Journal of the National Comprehensive Cancer Network 21, 3.5; 10.6004/jnccn.2022.7212
