Association between delays in adjuvant chemotherapy for stage III colon cancer and increased mortality.

Abstract

541 Background: Administration of adjuvant chemotherapy is the standard of care for stage III adenocarcinoma of the colon. There are conflicting data regarding the optimum interval for the initiation of adjuvant therapy and whether this affects survival. Methods: Patients were identified from the National Cancer Database (1998-2002) who received adjuvant chemotherapy after resection of stage III colon cancer. Multivariate analyses were performed to examine the associations between time interval from surgery to chemotherapy initiation and overall and relative survival. Relative survival was used as a surrogate for disease-specific survival. Results: 32,327 stage III colon cancer patients who received chemotherapy after surgery were identified. The relationship between timing of adjuvant chemotherapy and survival is reported in Table 1. Delay of chemotherapy beyond 8 weeks postoperatively was associated with an increased likelihood of death in a relative survival model, with a hazard ratio for death of 1.19 (95% CI: 1.11, 1.28) in the 8 to 12 week interval. Longer delays were associated with worse outcomes, with a 7.6% absolute decrease in relative survival. Other independent factors associated with reduced survival included gender, race, type of insurance, margin status, and tumor grade. Conclusions: Delay in the initiation of adjuvant therapy beyond eight weeks is an independent predictor of increased mortality. While other factors contribute to the risk of death from disease, chemotherapy delays may be preventable. Policy interventions should be developed to encourage the administration of chemotherapy within eight weeks of resection when indicated. Further effort should be expended to understand the etiology of and mitigate these delays. [Table: see text]