Factors affecting chemotherapy use and delay (≥ 8 weeks) after colorectal cancer surgery and the impact of chemotherapy delay on survival.

Abstract

784 Background: To date, reasons for adjuvant chemotherapy (AC) omission and delay have not been extensively studies. This study aimed to evaluate factors affecting chemotherapy use and delay (≥8 weeks) after colorectal cancer surgery and their impact on survival. Methods: Between 2008 and 2013, consecutive 584 patients undergoing major resection for stage II and III colorectal cancer in a single tertiary referral center. Results: Among 584 patients with stage II and III diseases, AC was performed in 460 (78.8%) patients. Regimens included fluorouracil with folinic acid (n=257, 55.9%), FOLFOX (n=134, 29.1%), capecitabline (n=62, 13.5%), and tegafur-uracil (n=7, 1.5%). Factors affecting not receiving AC were older age (>80 years), American Society of Anesthesiologists score (≥3), presence of postoperative complication, and not receiving preoperative chemoradiation. Overall survival was 87.2% (AC +) and 58.5% (no AC, p<0.001) in stage II disease, and 79.5% (AC +) and 24.6% (no AC, p<0.001) in stage III disease, respectively. Recurrence-free survival was 83.7% (AC +) and 61.9% (no AC, p=0.003) in stage II disease, and 60.5%(AC +) and 21.8% (no AC, p<0.001) in stage III disease, respectively. Among 460 patients undergoing AC, AC was initiated within 8 weeks in 438 patients (95.2%) and after 8 weeks in 22 patients (4.8%). Factors affecting AC delay were male gender, rectal primary, intraoperative blood loss (>100ml), and presence of postoperative complications. Overall survival was 90.8% (AC +) and 40.0% (no AC, p=0.111) in stage II disease, and 82% (AC +) and 35.6% (no AC, p=0.275) in stage III disease, respectively. Recurrence-free survival 80.1% (AC +) and 54.5% (no AC, p=0.133) in stage II disease, and 64.4% (AC +) and 0.0% (no AC, p=0.014), respectively. Conclusions: In stage II, III patients, it appears that use of AC is more closely related patient’s survival rather than the time of AC initiation. To improve oncologic outcomes after curative resection, it is important to increase the proporation of AC use.