Patterns of chemotherapy (CT) use in a U.S.-wide population-based cohort of patients (pts) with metastatic colorectal cancer (mCRC).

Abstract

3537 Background: Few population studies have examined treatment regimens and duration in mCRC since the introduction of biologic therapies in 2004. Methods: We assessed 4,877 consecutive mCRC pts who received CT between Jan 2004 and Mar 2011 at academic, private, and community hospital-based practices participating in a US-wide CT order entry (COE) system that captures patient demographics, stage and treatment data. Multivariate analyses of prospectively recorded patient and provider characteristics identified significant predictors of specific therapeutic approaches. Results: Among all pts, median age was 64; 55% male; (ECOG PS 0/1/2+) (56%/33%/11%). In first-line CT, 17% of pts received fluoropyrimidine (FU) only, while 16% received FU and irinotecan and 65% received FU and oxaliplatin. Older pts, those with poorer ECOG PS, and those treated in private practices were significantly more likely to receive FU only (all p ≤0.05). 53% of all pts received treatment in line 2, 28% in line 3, and 13% in line 4. Mean duration of treatment was 170 days (line 1), 139 (line 2), 135 (line 3) and 126 (line 4). Bevacizumab (bev) was administered to 65% of pts at some point in their treatment. Among the 51% who received bev in line 1, 33% continued bev beyond progression (BBP) in line 2. Pts treated at academic centers, pts who received longer duration of line 1 therapy, and pts whose providers had greater CRC pt volume were significantly more likely to continue BBP. Overall, 23% of pts received cetuximab (cet) (4% of all line 1 pts, 17% of line 2, 31% of line 3, and 29% of line 4). Mean duration of cet use was 168 days (line 1), 125 (line 2), 133 (line 3) and 129 (line 4). Pts treated at academic centers, pts who received longer duration of line 1 therapy, and pts treated in the West US were significantly more likely to ever receive cet. Cet use decreased by 18% following FDA label change restricting use to KRAS wt pts in Jun 2009 (p <0.001). Of all pts, 6% received panitumumab at some point. Of those, 39% had previously received cet. Conclusions: This population-based study provides insight into treatment patterns of mCRC in the US. Usage of biologic agents varies significantly according to patient, practice, and provider characteristics.