Adherence to stage-specific treatment guidelines for patients with colon cancer.

Objective: Adherence to evidence-based treatment guidelines has been proposed as a measure of cancer care quality. We sought to determine rates of and factors associated with adherence to the National Comprehensive Cancer Network (NCCN) treatment guidelines for colon cancer.

Methods: Patients within the National Cancer Data Base treated for colon adenocarcinoma (2003 to 2007) were identified. Adherence to stage-specific NCCN guidelines was determined based on disease stage. Hierarchical regression analyses were performed to identify factors predictive of adherence, overtreatment, and undertreatment.

Results: A total of 173,243 patients were included in the final cohort, 123,953 (71%) of whom were treated according to NCCN guidelines. Patients with stage I disease were more likely to receive guideline-based treatment (96%) than patients with stage II (low risk, 66%; high risk, 36%), III (71%), or IV (73%) disease (P < .001). Adherence to consensus-based guidelines increased over time. Factors associated with adherence across all stages included age, Charlson-Deyo comorbidity index score, later year of diagnosis, and insurance status. Among patients with high-risk stage II or stage III disease, older patients with pre-existing comorbidities and patients with lower socioeconomic status were less likely to be offered adjuvant chemotherapy. Among patients with stage I and II disease, young, healthy patients were more likely to be recommended chemotherapy, in discordance with NCCN guidelines.

Conclusions: Significant variation exists in the treatment of colon cancer, particularly in treatment of high-risk stage II and stage III disease. The impact of nonadherence to guidelines on patient outcomes needs to be further elucidated.