Sequential postoperative intraperitoneal chemotherapy for colorectal cancer with peritoneal metastases: a narrative review

Sequential postoperative intraperitoneal chemotherapy (SPIC) is a chemotherapy abdominal infusion given as a postoperative adjuvant treatment for 6 months after cytoreductive surgery (CRS) for peritoneal surface malignancies. It has most commonly been used in conjunction with ovarian cancer where the SPIC treatment has been integrated with adjuvant systemic chemotherapy. This review investigates the role of SPIC in the setting of colorectal cancer with peritoneal metastases. The focus is on the CRS+SPIC combination treatment with no systemic chemotherapy component. Several cohort studies, several comparative studies, and one randomized trial have been reported with several important endpoints. The following aspects will be covered in this review: overall survival, disease-free survival, morbidity, quality-of-life, and cost-effectiveness. In comparison to systemic chemotherapy alone for isolated resectable colorectal peritoneal metastases, CRS+SPIC is superior concerning overall survival, has no difference in morbidity, is similar in quality-of-life, and SPIC is cost-effective. In comparison to HIPEC, results are conflicting in multivariate analysis; but in a univariate analysis HIPEC (most often combined with systemic adjuvant therapy) appears superior to SPIC alone (no systemic component). The future of SPIC is uncertain. However, a combination of HIPEC and SPIC ± a systemic chemotherapy component is a possible direction to explore further.