Predictors of long‑term survival in patients with stage IV colorectal cancer with primary tumor resection: a multi-center retrospective analysis.

Background: Primary tumor resection is an option for patients with stage IV colorectal cancer (CRC). However, there is still no reliable strategy for predicting the survival of individual patients undergoing primary tumor resection (PTR). The aim of this study was to identify predictors of good prognosis in patients with stage IV CRC with PTR.

Methods: This is a retrospective analysis of patients with stage IV CRC who had undergone PTR in the Keio Surveillance Epidemiology and End Results (K-SEER) database. Clinical data and short- and long-term outcomes were analyzed. Univariate and multivariate analyses were performed using Cox proportional hazards model including all survival-related variables.

Results: Among 252 patients enrolled in this study, 176 had single-organ and 76 had multi-organ metastases. Seventy-seven patients did not receive chemotherapy after primary tumor resection. Three patients consequently underwent curative metastasectomy after PTR. Multivariate Cox analysis revealed age, number of organs with metastasis, and chemotherapy after PTR were independently associated with both Overall Survival (OS) and Cancer-Specific Survival (CSS). In the subgroup analysis, the survival rate was significantly lower in patients with multi-organ metastases than in those with single-organ metastases, both in 3-year OS (47.69% vs 23.20%; log-rank P < 0.001) and 3-year CSS (54.45% vs 30.48%; log-rank P < 0.001).

Conclusions: This study demonstrated that multi-organ metastasis was a prognostic factor for poor prognosis in patients with stage IV CRC patients who underwent PTR. These findings could support surgeons to make better clinical decisions for patients with stage IV CRC.