OBJECTIVE: We retrospectively evaluated the impact of postoperative complications on long-term outcomes after curative resection for colorectal cancer (CRC), using propensity-score analysis (PSA). PATIENTS AND METHODS: We reviewed data from 673 consecutive patients with stage I to III CRC, who underwent curative resections between 2005 and 2017. Patients were divided into the complication group (Clavien-Dindo [CD] grade ≥ 3) and the control group (others). We performed PSA to obtain unbiased estimates of the effects of the oncological background on each outcome. RESULTS: We matched for sex, age, American Society of Anesthesiologists grade, location (right colon/left colon/rectum), histology (tub1/tub2/por), pathological tumor depth, and lymph node metastases. Eighty-five patients (12.6%) developed postoperative complications with CD grade ≥ 3. After PSA, 81 patients were included in each group. The complication group showed significantly worse relapse-free survival (RFS) than the control group (5-year RFS rate: 62% vs 77%; P = .047). In multivariate analysis with inverse probability of treatment weights, the complication group had a higher risk of relapse or death than the control group (hazard ratio: 2.08, 95% confidence interval:1.3-3.3; P = .018). CONCLUSIONS: Postoperative complications (CD grade ≥ 3) could cause poor long-term outcomes in patients with stage I to III CRC; their presence requires appropriate adjuvant chemotherapy and follow-up.
OBJECTIVE: We retrospectively evaluated the impact of postoperative complications on long-term outcomes after curative resection for colorectal cancer (CRC), using propensity-score analysis (PSA). PATIENTS AND METHODS: We reviewed data from 673 consecutive patients with stage I to III CRC, who underwent curative resections between 2005 and 2017. Patients were divided into the complication group (Clavien-Dindo [CD] grade ≥ 3) and the control group (others). We performed PSA to obtain unbiased estimates of the effects of the oncological background on each outcome. RESULTS: We matched for sex, age, American Society of Anesthesiologists grade, location (right colon/left colon/rectum), histology (tub1/tub2/por), pathological tumor depth, and lymph node metastases. Eighty-five patients (12.6%) developed postoperative complications with CD grade ≥ 3. After PSA, 81 patients were included in each group. The complication group showed significantly worse relapse-free survival (RFS) than the control group (5-year RFS rate: 62% vs 77%; P = .047). In multivariate analysis with inverse probability of treatment weights, the complication group had a higher risk of relapse or death than the control group (hazard ratio: 2.08, 95% confidence interval:1.3-3.3; P = .018). CONCLUSIONS: Postoperative complications (CD grade ≥ 3) could cause poor long-term outcomes in patients with stage I to III CRC; their presence requires appropriate adjuvant chemotherapy and follow-up.