The effect of time interval from chemoradiation to surgery on postoperative complications in patients with rectal cancer

BACKGROUND: A prolonged time interval between chemoradiation and total mesorectal excision (TME) may render more rectal cancer patients eligible for organ-sparing approaches but may also cause more pelvic fibrosis and surgical morbidity. We estimated the effect of time interval on postoperative complications and other surgical outcomes in rectal cancer patients. METHODS: This is a population-based cohort study using data of the Dutch Colorectal Audit. Rectal cancer patients treated with chemoradiation followed by TME after an interval of 3-20 weeks were selected (n = 6,268). Time interval from completion of chemoradiation to TME was categorized into 3-6, 7-8, 9-10, 11-12 and 13-20 weeks. Outcomes included postoperative complication (any, and stratified by medical and surgical complications), reintervention, intraoperative complication, incomplete resection, positive circumferential margin (CRM) and pathological complete response (pCR). The interval of 7-8 weeks was the reference group. RESULTS: Prolonged time intervals were not associated with a higher risk of a postoperative complication (any, surgical or medical), reintervention, and incomplete resection. Intraoperative complications were however more common after 11-12 weeks than after 7-8 weeks (odds ratio (OR) = 1.79, 95% confidence interval (CI) = 1.20-2.69). The interval of 9-10 weeks was associated with less CRM positive resections, and 9-10 and 13-20 weeks with more pCR (relative to 7-8 weeks, OR = 0.74, 95%CI = 0.56-0.98; OR = 1.28, 95%CI = 1.04-1.58; and OR = 1.33, 95%CI = 1.04-1.71, respectively). CONCLUSIONS: Compared with 7-8 weeks, longer time intervals up to 13-20 weeks between chemoradiation and TME are not associated with more postoperative complications or more positive resection margins. Accordingly, prolonging the interval aiming for organ-sparing treatment is safe