Abstract
BackgroundIn 2009, treatment guidelines were updated to recommend KRAS testing at diagnosis for patients with metastatic colorectal cancer (mCRC). We investigated KRAS testing rates over time and compared characteristics of KRAS-tested and not-tested patients in a community-based oncology setting.MethodsAdult patients with a diagnosis of mCRC from 2008–2011 were selected from the ACORN Data Warehouse (ACORN Research LLC, Memphis, TN). Text mining of physician progress notes and full chart reviews identified KRAS-tested patients, test dates, and test results (KRAS status). The overall proportion of eligible patients KRAS-tested in each calendar year was calculated. Among KRAS-tested patients, the proportion tested at diagnosis (within 60 days) was calculated by year. Univariate and multivariate analyses were used to compare patient characteristics at diagnosis between tested and not-tested cohorts, and to identify factors associated with KRAS testing.ResultsAmong 1,363 mCRC patients seen from 2008–2011, 648 (47.5%) were KRAS-tested. Among newly diagnosed mCRC patients, the rate of KRAS testing increased from 5.9% prior to 2008, to 13.9% in 2008, and then jumped dramatically to 32.3% in 2009, after which a modest yearly increase continued. The proportions of KRAS-tested patients who had been diagnosed in previous years but not tested previously increased from 17.7% in 2008 to 27.0% in 2009, then decreased to 19.0% in 2010 and 17.6% in 2011. Among patients who were KRAS-tested, the proportions tested at the time of diagnosis increased annually (to 78.4% in 2011). Patients more likely to have been tested included those with lung metastases, poor performance status, more comorbidities, and mCRC diagnosis in 2009 or later.ConclusionsThe frequency of KRAS testing increased over time, corresponding to changes in treatment guidelines and epidermal growth factor receptor inhibitor product labels; however, approximately 50% of eligible patients were untested during the study period.
Highlights
In 2009, treatment guidelines were updated to recommend KRAS testing at diagnosis for patients with metastatic colorectal cancer
One limitation is that the results of KRAS testing are not captured in standard Electronic medical record (EMR) data fields; this information is often found in physician progress notes, which ACORN stores electronically in the data warehouse to complement the EMR data
Patients tested for KRAS were less likely to be self-pay (3.9% vs. 8.1% for not-tested patients, p = 0.040), were more likely to be enrolled in a clinical trial (13.7% vs. 8.7%, p = 0.003), had more comorbid conditions, and had poorer performance status (ECOG 2–4: 41.9% vs. 34.0%, p = 0.042) at diagnosis
Summary
In 2009, treatment guidelines were updated to recommend KRAS testing at diagnosis for patients with metastatic colorectal cancer (mCRC). At the time of diagnosis, approximately 39% of patients with CRC present with localized disease (stages I-II), 37% present with regional metastases (stage III), and 19% with distant metastases (stage IV, or metastatic CRC [mCRC]) [2]. In mCRC, common sites for metastases include the liver, Conventional chemotherapies used to treat mCRC include combinations of 5-fluorouracil, leucovorin, capecitabine, oxaliplatin, and irinotecan [4]. Bevacizumab (Avastin) is indicated for treatment of mCRC in combination with conventional chemotherapies [5]. In 2004, the EGFR inhibitor cetuximab (Erbitux) was approved in the US for the second-line treatment of Carter et al Journal of Experimental & Clinical Cancer Research (2015) 34:29
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