A total of 3599 patients with stage I-III colorectal adenocarcinoma who underwent radical surgery in Yunnan Cancer Hospital from 2008 to 2019 were selected. In strict adherence with the inclusion and exclusion criteria, 406 patients with recurrence after radical resection were enrolled. According to recurrence within 2 years, 252 cases of early recurrence and 154 cases of late recurrence were identified. According to the recurrence pattern, 31 cases of local recurrence, 315 cases of distant metastasis, and 60 cases of simultaneous recurrence were identified. Based on the recurrence site, 98 cases (24.14%) of pure liver metastasis, 127 cases (31.28%) of pure lung metastasis, 32 cases (7.88%) of peritoneal metastasis, 69 cases (17.00%) of metastasis to other individual organs, and 49 cases (12.07%) of metastasis to two or more organ or sites were identified (Fig. 1). The median patient age was 60 years (range 21–87 years). Two hundred and twenty (54.19%) patients were males. The median RFS was 11.90 months (range 0.27–66.67 months). After at least 3 years of follow-up, 235 (57.88%) patients died (Table 1).

The 3-year PRS rate of 252 patients with early relapse was 44.59% (95% CI, 38.85%-51.19%), whereas the 3-year PRS rate of 154 patients with late recurrence was 53.28% (95% CI, 46.20%-61.45%) (HR, 0.78; 95% CI, 0.59–1.02; P = 0.0717) (Table 2 and Fig. 2A). The 3-year PRS of patients with local recurrence was 66.83% (95% CI, 53.04%-84.22%), and the 3-year PRS of patients with distant metastasis was 49.41% (95% CI, 44.16%-55.27%), which were significantly greater than the 3-year PRS in patients with synchronous recurrence and metastasis (30.32%; 95% CI, 21.10%-43.56%) (Table 2 and Fig. 2B). The 3-year PRS of patients with simple liver metastases was 54.04% (95% CI, 45.46%-64.24%), and the 3-year PRS of patients with simple pulmonary metastases was 50.05% (95% CI, 42.50%-58.95%). No significant difference was observed in patients with relapse. The 3-year PRS of patients with peritoneal metastases was 25.43% (95% CI, 14.76%-43.82%), and the 3-year PRS of patients with metastases to two or more organs was 34.84% (95% CI, 24.16%-50.24%) (Table 2 and Fig. 2C).

There was no significant difference in the PRS between patients with early recurrence and late recurrence (A). The PRS of synchronous recurrence was significantly lower than that of distant metastasis. Patients with local recurrence had the longest survival (B). The PRS of patients with metastasis to the peritoneum or two or more organs or sites was significantly lower than that of patients with recurrence in other sites (C). PRS: Post-recurrence survival rate

Univariate and multivariate analyses of the factors associated with PRS are shown in Table 2. Univariate analysis showed that peritoneal metastasis, metastasis to two or more organs or sites, distant metastasis, right colon and rectal cancer, later pathological N stage, vascular invasion, tumor deposition, preoperative CEA, CA199 elevation, and postoperative CEA elevation were associated with a shorter PRS. Metastasis to the peritoneum (hazard ratio [HR], 1.75; 95% CI, 1.10–2.79; P = 0.0189) and two or more organs or sites (HR, 1.59; 95% CI, 1.05–2.43; P = 0.0189) in multivariate analysis (0.0304) along with a later pathological N stage was an independent poor prognostic factor for PRS (Table 2).

The 3-year PRS rate was 25.43% (95% CI, 14.76%-43.82%) in patients with peritoneal recurrence, in contrast to 49.89% (95% CI, 44.96%-55.36%) in patients without peritoneal recurrence (HR, 1.97; 95% CI, 1.30–2.98; P = 0.0015) (Table 2 and Fig. 3C). The 3-year PRS rate was 34.84% (95% CI, 24.16%-50.24%) in patients with recurrence in two or more organ sites, whereas in patients with recurrence in other individual organs (including liver alone, lung alone, peritoneum, local metastasis, or metastasis in other sites), the 3-year PRS rate was 49.68% (95% CI, 44.67%-55.26%) (HR, 1.51; 95% CI, 1.04–2.18; P = 0.0296) (Table 2 and Fig. 3E). The 3-year PRS rate was 66.99% (95% CI, 53.23%-84.32%) in patients with local recurrence, compared with 46.47% (95% CI, 41.59%-51.93%) in patients without local recurrence (HR, 0.51; 95% CI, 0.29–0.94; P = 0.0310) (Table 2 and Fig. 3F). No significant difference was observed in the 3-year PRS between patients with and without liver metastases alone, lung metastases alone, and metastases to other individual organs (P > 0.05) (Fig. 3A, B, D).

Patients with metastasis to the peritoneum or two or more organs or sites and local recurrence had worse PRS than patients without metastasis to the peritoneum or two or more organs or sites and local recurrence (C, E, and F). No significant differences were observed in the PRS of patients with or without recurrence at other sites (A, B, and D). PRS: Post-recurrence survival