The clinical impacts of postoperative complications after colon cancer surgery for the clinical course of adjuvant treatment and survival

Aim We investigated whether or not postoperative complications (POCs) themselves have a negative survival impact or indirectly worsen the survival due to insufficient adjuvant chemotherapy in a pooled analysis of two large phase III studies performed in Japan Patients and methods The study examined the patients who enrolled in 1304, phase III study comparing the efficacy of 6 and 12 months of capecitabine as adjuvant chemotherapy for stage III colon cancer patients and in 882, a phase III study to confirm the tolerability of oxaliplatin, fluorouracil, and l-leucovorin in Japanese stage II/III colon cancer patients. In our study, POCs were defined as the following major surgical complications: anastomotic leakage, pneumonia, bowel obstruction/ileus, surgical site infection, postoperative bleeding, urinary tract infection, and fistula. Patients were classified as those with POCs (C group) and those without POCs (NC group). Results A total of 2095 patients were examined in the present study. POCs were observed in 169 patients (8.1%). The overall survival (OS) rates at 5 years after surgery were 75.3% in the C group and 86.5% in the NC group ( p = 0.0017). The hazard ratio of POCs for the OS in multivariate analysis was 1.70 (95% confidence interval, 1.19 to 2.45; p = 0.0040). The time to adjuvant treatment failure (TTF) of adjuvant chemotherapy was similar between the groups, being 68.6% in the C group and 67.1% in the NC group for the 6-month continuation rate of adjuvant chemotherapy. The dose reduction rate of adjuvant chemotherapy and adjuvant treatment suspension rate were also similar between the groups (C vs. NC groups: 45.0% vs. 48.7%, p = 0.3520; and 52.7% vs. 55.0%, p = 0.5522, respectively). Conclusion POCs were associated with a poor prognosis but did not affect the intensity of adjuvant chemotherapy. These results suggested that POCs themselves negatively influence the survival.