Factors Affecting Use and Delay (≥8 Weeks) of Adjuvant Chemotherapy after Colorectal Cancer Surgery and the Impact of Chemotherapy-Use and Delay on Oncologic Outcomes.

To evaluate factors affecting the use and delay ≥8 weeks of adjuvant chemotherapy and the impact of chemotherapy use and delay on survival.Between 2005 and 2012, consecutive patients with stage II and III colorectal cancer who were treated with major curative resection were enrolled.Among 750 patients with stage II (n = 318) and III (n = 432) disease, 153 (20.4%) did not receive chemotherapy. Among 597 patients with adjuvant chemotherapy, 31 (5.2%) began chemotherapy 8 weeks or more after surgery. Factors associated with not receiving chemotherapy were: age ≥80 years (hazard ratio [HR] = 5.2), American Society of Anesthesiologists score ≥3 (HR = 1.9), underlying cerebrovascular disease (HR = 1.7), stage II disease (HR = 2.0), presence of postoperative complications (HR = 2.2), or intensive care unit admission (HR = 2.4). Factors associated with chemotherapy delay ≥8 weeks were: male sex (HR = 4.2), rectal primary cancer (HR = 5.4), or presence of postoperative complications (HR = 2.5). Independent prognostic factors for overall survival included TNM III stage (HR = 2.04) and chemotherapy delay ≥8 weeks (HR = 0.39) or <8 weeks (HR = 0.22). Independent prognostic factors for recurrence-free survival were TNM III stage (HR = 2.26) and chemotherapy delay <8 weeks (HR = 0.35).Postoperative complications were associated with both lack of and delayed chemotherapy. Timely initiation of chemotherapy, defined as