Treatment patterns and survival outcomes for patients receiving second-line treatment for metastatic colorectal cancer in the USA

Background Colorectal cancer is the third most common cause of cancer death in the USA. It is important to identify patients who may experience poor outcomes from available treatments. Methods In this retrospective observational study, treatment patterns and survival outcomes were described among adult patients from the Flatiron Health electronic medical records database who were treated with at least two lines of therapy for metastatic colorectal cancer in the USA between January 2013 and May 2018. Patients with rapid progression were defined as those whose time from start of first- to second-line therapy was <= 183days. Results A total of 14,315 patients formed the study cohort. The most common first-line treatments were FOLFOX (5-fluorouracil, leucovorin, and oxaliplatin) plus bevacizumab, received by 34.7% (n = 4962) of patients, followed by FOLFOX alone (17.1%, n = 2445). Of all patients, 6991 (48.9%) also received second-line anti-cancer therapy and of those, 3338 (47.7%) had rapid progression and 3653 (52.3%) did not. Median overall survival from the start of first-and second-line therapy was 20.8months (95% CI 20.2-21.3) and 14.5 months (95% CI 13.9-15.0) for the entire study population, respectively. Median overall survival from the start of second-line therapy was 14.1 (95% CI 13.2-14.8) for patients with rapid progression and 14.6months (95% CI 13.8-15.4) for patients without rapid progression. Conclusions Patients diagnosed with metastatic colorectal cancer lived less than 2years in this real-world database. While the time to initiation of second-line therapy was by definition longer among patients without rapidly progressing disease, survival outcomes were comparable from initiation of second-line therapy.