OBJECTIVES: Colorectal cancer (CRC) is the fourth most common cancer and second most common cause of cancer death in the United States (US), with an estimated 147,950 new cases of CRC and 53,200 CRC-related deaths in 2020. At initial diagnosis, approximately 22% of patients present with metastatic disease (mCRC), which has a 5-year survival of 14.3%. This real-world study describes the demographic and clinical characteristics and systemic treatment patterns in US patients with mCRC.

METHODS: This retrospective observational cohort study included adults in the IBM® MarketScan® Research database with: ≥1 inpatient or ≥2 outpatient claims with a diagnosis of mCRC from 1/1/2015–12/31/2019; National Comprehensive Cancer Network guideline-recommended systemic treatment for mCRC on/after metastatic diagnosis date (first treatment date=index date); and ≥12 months continuous plan enrollment before and after the index date. Patient characteristics and the most frequently used treatment regimens by line of therapy (LOT) were summarized. Agents initiated within 60 days of a new LOT were included in that line; a treatment gap of 120 days between agents was considered a new LOT.

RESULTS: 2,426 patients were included; 57% were male and mean age at diagnosis was 56 years. Left-sided tumors were more common than right-sided. FOLFOX-based regimens were most common in the first line (1L) setting (64%) and FOLFIRI-based regimens were more common in 2L (24%). After 1L, 43% of patients received 2L treatment, of which 39% subsequently received 3L treatment. Regimens used in 3L and 4L contained a wider variety of chemotherapy backbones. Use of targeted therapy was uncommon; anti-EGFR regimen use was ~26% and PD-1 inhibitor use was ~3% in later lines. Less than 1% of patients received HER2-targeted therapy.

CONCLUSIONS: After 2L, there is increasing variability in treatment regimens and reuse of prior chemotherapies. Findings suggest there is currently limited use of biomarker-driven treatments among US patients with mCRC.