[Can the weekday of surgery influence the prognosis of colorectal cancer patients? A retrospective study based on a single-center of large sample].

To investigate the impact of the weekday of surgery on the prognosis of patients with colorectal cancer.A retrospective analysis was conducted in patients with colorectal cancer who underwent radical resection in Fudan University Shanghai Cancer Center(FUSCC) between January 2007 and December 2013, and 4 971 patients were identified eligible. Statistical analyses were carried out between patients who received surgery on Monday to Thursday and those who received surgery on Friday. Chi-square test was used to analyze the relationship between clinicopathological parameters and day of surgery. T test was used to compare continuous variables between groups. The 5-year overall survival (OS) and disease-free survival (DFS) were calculated by the Kaplan-Meier method, and compared by log-rank test.There were no statistically significant differences between two groups in age, gender and pathological grade et al (all P>0.05). However, the number of dissected lymph node was higher in patients who received surgery on Monday to Thursday (median 16) compared with patients who received surgery on Friday (median 14), with statistically significant difference (P=0.038). The 5-year OS and DFS in all eligible patients were 78.0% and 55.0%, respectively. 5-year OS of patients in Monday to Thursday surgery group and Friday surgery group was 79.6% and 77.2%, while 5-year DFS in two groups was 57.8% and 50.4%. There were no significant differences in OS and DFS between two group, with P=0.882 and P=0.210, respectively. Subgroup analyses were conducted according to different pathological stages. 5-year OS of patients at stage I( in Monday to Thursday surgery group and Friday surgery group was 94.7% and 90.6% (P=0.742) and 5-year DFS was 85.1% and 78.2% (P=0.765). 5-year OS of patients at stage II( in two groups was 85.5% and 83.7% (P=0.496) and 5-year DFS was 72.7% and 62.8% (P=0.121). 5-year OS of patients at stage III( in two groups was 69.7% and 69.4%(P=0.354) and 5-year DFS was 41.8% and 37.4% (P=0.976). No statistically significant differences manifested in subgroup analyses.Patients with colorectal cancer undergoing surgery on Monday to Thursday have similar long-term prognosis with those on Friday.