Hospital Variability in Use of Adjuvant Chemotherapy for Patients with Stage 2 and 3 Colon Cancer

Abstract

Following oncologic resection, adjuvant chemotherapy is associated with decreased recurrence and improved survival in stage 3 colon cancer. However, there is controversy regarding its use in stage 2 colon cancer with high-risk features (tumor depth T4, poorly differentiated, positive margin, and/or inadequate lymph node retrieval). Consensus guidelines recommend no adjuvant chemotherapy in the absence of these high-risk features (low-risk stage 2). This study aimed to examine hospital characteristics associated with poor risk-adjusted, stage-specific guideline compliance for the use of adjuvant chemotherapy in stage 3 and low-risk stage 2 colon cancer. This was a retrospective study. Stepwise logistic regression was used to identify patient and hospital factors associated with administration of adjuvant chemotherapy. Hierarchical regression models were used to calculate risk- and reliability-adjusted rates of chemotherapy use and observed-to-expected ratios in each hospital's stage 2 low-risk and stage 3 patients. Data were retrieved from the National Cancer Database. Patients selected were adults treated with oncologic resection for stage 2 to 3 colon cancer between 2004 and 2010. The primary outcome measured was receipt of adjuvant chemotherapy. A total of 167,345 patients were identified at 1395 hospitals. The mean overall risk-adjusted adjuvant chemotherapy rate was 65.3% for stage 3 and 15.2% for low-risk stage 2. Analysis of low outlier hospitals for stage 3 colon cancer, where adjuvant chemotherapy was underutilized, demonstrated that 62.8% were low-volume centers and 51.4% were community centers. Of high outlier hospitals for stage 2 low-risk disease, where adjuvant chemotherapy was overutilized, 87.2% were low-volume hospitals and 67.2% were community centers. Selection bias and the inability to compare specific chemotherapy regimens were limitations of this study. Following oncologic resection, administration of adjuvant chemotherapy for low-risk stage 2 and stage 3 disease varies substantially among hospitals in the United States. Outlier hospitals were most likely to be low-volume community centers.