Abstract and Introduction
Abstract
Background. Since the introduction of biologic therapies for the treatment of metastatic colorectal cancer (mCRC), few studies have examined patterns of care or predictors of specific treatment approaches.
Methods. We assessed 4877 mCRC patients who received chemotherapy between January 2004 and March 2011 at academic, private, and community-based oncology practices subscribing to a US-wide chemotherapy order entry (system capturing disease, patient, provider, and treatment data. Multivariable analyses of these prospectively recorded characteristics were used to identify independent predictors of specific therapeutic choices. All statistical tests were two-sided.
Results. Throughout the study period, fluoropyrimidine/oxaliplatin combination was the most commonly used first-line chemotherapy regimen, representing 71% of first-line therapy by 2007. First-line bevacizumab use averaged 51%, peaking at 55% in 2006. Of those who received first-line bevacizumab, 34% continued to receive bevacizumab in the second-line. Only 26% of patients in our cohort ever received an anti-EGFR monoclonal antibody (cetuximab = 22%; panitumumab = 6%) at some point in their treatment course. Patients treated at academic centers, with longer duration of first-line therapy, and at sites in the western United States were statistically more likely to receive an anti-EGFR antibody. Anti-EGFR antibody use fell by 18% after the US Food and Drug Administration limited its use to patients with KRAS wild-type tumors in June 2009.
Conclusions. Analysis of this US-wide mCRC cohort demonstrates that bevacizumab has been more consistently integrated into treatment regimens than anti-EGFR antibody therapies, particularly in first-line therapy. However, treatment choices vary substantially according to specific patient, practice, and provider characteristics.
Introduction
Between 2004 and 2007, bevacizumab, cetuximab, and panitumumab were approved for the treatment of metastatic colorectal cancer (mCRC) based on randomized clinical trials that demonstrated important improvements in patient outcome. However, the optimal use and sequence of these agents remains uncertain. Moreover, data on how these agents are used in routine clinical practice are limited.
Few studies have examined administration frequencies of specific chemotherapeutic regimens and the predictors of their usage. Existing studies were conducted in limited practice settings or relied on retrospective medical record extraction, physician surveys, market research, or insurance claims data to ascertain use. To better delineate factors influencing treatment choices, we analyzed data from a nationwide, commercially available chemotherapy order entry (COE) system that provided tumor stage, disease status, and treatment indication. Within this database, we identified temporal trends in prescribing patterns across the continuum of mCRC therapy and identified patient and provider characteristics that influenced treatment selection across multiple lines of therapy.