Clinicopathological Parameters in Patient Selection for Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Colorectal Cancer Metastases A Meta-analysis

Objective: To improve patient selection for cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) by evaluating various preoperatively assessable clinicopathological parameters as markers for survival after CRS and HIPEC. Summary Background Data: Peritoneal metastases (PMs) originating from colorectal cancer are treated with CRS and HIPEC. Despite increasing survival, high morbidity and mortality warrant selection of patients with optimal benefit from this treatment. Many studies report a number of variables to be associated with survival after CRS and HIPEC, but no definitive analysis has been made to validate various markers. Methods: In concordance with PRISMA guidelines, we performed a literature search encompassing 4110 articles to select 50 articles that reported the influence of 1 or more clinicopathological variables on overall survival after CRS and HIPEC. In absence of RCTs, 25 cohort studies could be used to perform a meta-analysis on 10 prognostic variables. Results: We determined that concurrent liver metastasis, lymph node metastasis, Eastern Cooperative Oncology Group score, tumor differentiation, and signet ring cell histology are all negative prognostic variables on overall survival after CRS and HIPEC. Conversely, sex and location of primary could not be validated as prognostic markers. More research is required to make definitive conclusions about neoadjuvant chemotherapy, onset of PMs, and mucinous histology. Conclusions: Current clinical practice, which selects patients based on extraperitoneal metastasis, lymph node stage, performance status, and tumor histology, is validated by our pooled analysis. Our data merit further research into neoadjuvant chemotherapy in the setting of CRS and HIPEC for PMs.