Patterns of adjuvant chemotherapy use in a population-based cohort of patients with resected stage II or III colon cancer.

PURPOSE: Previous studies have examined predictors for initiation of adjuvant chemotherapy in stages II and III colon cancer. However, little is known regarding the use of specific chemotherapy regimens or treatment duration. PATIENTS AND METHODS: We studied treatment records for 2,560 patients with stage II or III colon cancer who received adjuvant chemotherapy between January 2004 and April 2010 at US cancer care facilities participating in a nationwide, commercially available chemotherapy order entry system that captures patient demographics, stage, and details of chemotherapy treatment. Multivariate analyses of prospectively recorded patient and provider characteristics identified predictors of specific therapeutic approaches.
RESULTS: The addition of oxaliplatin to fluoropyrimidine-based adjuvant therapy increased during the study period (P trend < .001), and this combination represented 78% and 90% of adjuvant chemotherapy in stage II or III disease, respectively, by 2007. Older patients, those with diminished performance status, and those treated in a private practice setting were significantly less likely to receive oxaliplatin. Thirty percent of patients discontinued adjuvant therapy after less than 3 months. Older age, treatment without oxaliplatin, and receipt of treatment from a physician with a low volume of patients were each independently associated with premature discontinuation [corrected]. Six percent of patients received bevacizumab as part of their adjuvant regimen.
CONCLUSION: After 2004, oxaliplatin and fluoropyrimidine-based therapy rapidly became the predominant adjuvant treatment for both stage II and stage III colon cancer in this large US cohort. Both increasing patient age and lower volume of an oncologist's practice were associated with early termination of adjuvant therapy.