Association of Systemic Chemotherapy Approaches With Outcomes in Appendiceal Peritoneal Metastases

Many patients undergoing cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) for appendiceal adenocarcinoma peritoneal metastases (APM) undergo preoperative systemic chemotherapy. The primary aim of this study is to evaluate differences in oncologic outcomes among two popular chemotherapy approaches in patients with APM undergoing CRS-HIPEC. We performed a multicenter retrospective review of patients who underwent CRS-HIPEC for APM due to high or intermediate grade disease between 2013 and 2019. Patients in the total neoadjuvant therapy group (TNT) received 12 cycles of preoperative chemotherapy. Patients in the “sandwich” chemotherapy group (SAND) received six cycles of preoperative chemotherapy with a maximum of six cycles of postoperative chemotherapy. The primary outcomes were overall survival (OS) and recurrence-free survival (RFS) defined as months from date of first treatment or surgery, respectively. A total of 39 patients were included in this analysis, with 25 (64%) patients in the TNT group and 14 (36%) patients in the SAND group. Patients in the TNT group had a median OS of 62 mo, while median OS in the SAND group was 45 mo (P = 0.01). In addition, patients in the TNT group had significantly longer RFS compared to the SAND group (35 versus 12 mo, P = 0.03). In a multivariable analysis, TNT approach was independently associated with improved OS and RFS. In this multicenter retrospective analysis, a TNT approach was associated with improved overall and recurrence-free survival compared to a sandwiched chemotherapy approach in patients undergoing CRS-HIPEC for high or intermediate grade APM. •A total neoadjuvant chemotherapy method associates with improved oncologic outcomes.•A sandwiched chemotherapy approach associates with worse oncologic outcomes.•One-third of patients did not complete their scheduled adjuvant chemotherapy course.•These findings establish foundational data for future prospective studies.