Pre-operative predictors of completeness of cytoreduction for colorectal peritoneal metastases: a systematic review of radiological, clinicopathological and biomarker-based predictors.

BACKGROUND

Complete cytoreduction is a critical prognostic indicator for patients with colorectal cancer peritoneal metastases. This study aimed to identify pre-operative predictors of completeness of cytoreduction in patients with colorectal peritoneal metastases.

METHODS

A systematic review was conducted following PRISMA guidelines and registered with PROSPERO. A comprehensive literature search was performed using OVID Medline, EMBASE and EMBASE Classic to identify English-language studies involving human subjects published between 2000 and 2025. This review included studies involving patients with colorectal peritoneal metastases who underwent cytoreductive surgery with curative intent. Eligible studies specifically assessed pre-operative predictors of achieving complete cytoreduction. Case reports, systematic reviews, and animal studies were excluded, as were studies that assessed intra-operative or post-operative predictors.

RESULTS

Of 394 non-duplicate records screened, 21 studies met inclusion criteria. Radiological, clinicopathological, and biomarker-based predictors have been extensively evaluated for their association with cytoreduction completeness in colorectal peritoneal metastases. Statistically significant predictors of incomplete cytoreduction included: CT-detected ascites, elevated tumour markers, high C-reactive protein, hypoalbuminemia, signet ring cell carcinoma, mucinous adenocarcinoma, male gender, bowel obstruction, prolonged lead time to surgery, and incomplete diagnostic laparoscopy. In contrast, tumour location, tumour and nodal staging, liver metastases, and synchronicity of peritoneal metastases were not significant.

CONCLUSIONS

Pre-operative predictors of cytoreduction completeness in colorectal peritoneal metastases have been identified in the radiological, pathological, and biomarker-based domains. However, there is substantial heterogeneity in how completeness of cytoreduction is defined across studies. Multicentre and prospective studies are needed to integrate these predictors to improve patient selection for cytoreductive surgery.