Reported outcomes following cytoreductive surgery for colorectal peritoneal metastases: A systematic review to inform evidence-based practice and international consensus

Aim: Cytoreductive surgery provides a chance for long-term survival and cure in selected patients with colorectal peritoneal metastases. As clinical and academic interest in this field increases, heterogeneity in outcome reporting hinders the valid and meaningful synthesis of data into high-quality meta-analyses. The aim of this systemic review was to investigate variability in outcome reporting following cytoreductive surgery with or without intraperitoneal chemotherapy for colorectal peritoneal metastases.

Method: Five electronic databases [MEDLINE, Embase, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL) and Cumulative Index to Nursing and Allied Health Literature (CINAHL)] were interrogated from 2000 to October 2023 to identify all reported outcomes in the current literature. Extracted outcomes were catalogued and reviewed by a multidisciplinary working group into standardized terms and domains.

Results: A total of 294 studies, from 5112 screened, were included for analysis. We extracted 2903 outcomes verbatim from included studies and catalogued them into 85 standardized outcomes across seven outcome domains. The most frequently reported domains were survival, in 274 (93%) studies, and pathological outcomes, in 232 (79%) studies. Outcomes pertaining to function and life impact were only reported in seven (2%) studies. Reported outcomes were only defined in 35% of cases, and significant variability existed between definitions.

Conclusion: This systematic review highlights the heterogeneity of outcome measurement and reporting following cytoreductive surgery for colorectal peritoneal metastases. Patient-reported outcomes are relatively underrepresented in the current literature. The results of this review will inform an international collaborative effort to create a core outcome set to address these issues.