Influence of the initial recurrence site on prognosis after radical surgery for colorectal cancer: a retrospective cohort study

In this retrospective study, we aimed to elucidate how the initial recurrence site influences the post-recurrence survival (PRS) after the curative resection of colorectal cancer. We collected samples from patients with stage I-III colorectal adenocarcinoma who were admitted to Yunnan Cancer Hospital from January 2008 to December 2019. Four hundred and six patients who developed recurrence after radical resection were included. The cases were classified according to the original site of recurrence as follows: liver metastases (n = 98), lung metastases (n = 127), peritoneum (n = 32), other individual organ (n = 69), two or more organs or sites (n = 49), and local recurrence (n = 31). Kaplan-Meier survival curves were used to compare the PRS of patients with different initial sites of recurrence. The influence of the initial recurrence site on PRS was analyzed using the Cox proportional hazards model. The 3-year PRS of simple liver metastasis was 54.04% (95% CI, 45.46%-64.24%), and the 3-year PRS of simple lung metastasis was 50.05% (95% CI, 42.50%-58.95%). No significant difference was observed between simple liver metastasis or simple lung metastasis and local recurrence with a 3-year PRS of 66.99% (95% CI, 53.23%-84.32%). The 3-year PRS for peritoneal metastases was 25.43% (95% CI, 14.76%-43.82%), and the 3-year PRS for two or more organ sites was 34.84% (95% CI, 24.16%-50.24%). The peritoneal (hazard ratio [HR], 1.75; 95% CI, 1.10-2.79; P = 0.0189) and metastasis to two or more organs or sites (HR, 1.59; 95% CI, 1.05-2.43; P = 0.0304) were PRS-independent adverse prognostic factors. The prognosis of patients with peritoneum and multiple organs or sites recurred was poor. This study suggests early monitoring of peritoneal and multiple organ or site recurrence after surgery. This part of patients should receive comprehensive treatment as early as possible to improve their prognosis.