Outcomes of neoadjuvant chemotherapy before CRS-HIPEC for patients with appendiceal cancer

Cytoreductive surgery (CRS) with or without hyperthermic intraperitoneal chemotherapy (HIPEC) is indicated for patients with peritoneal dissemination of appendiceal cancer. The role of neoadjuvant chemotherapy (NAC) before CRS-HIPEC remains controversial.

A retrospective review of adult patients who underwent CRS ± HIPEC for metastatic appendiceal cancer between 2000-2017 was performed. Patients who received NAC followed by surgery were compared with those who underwent surgery first (SF) with and without 1:1 propensity score matching (PSM).

Among 803 patients with appendiceal cancer who underwent CRS ± HIPEC, 225 (28%) received NAC, and 578 (72%) underwent SF. After PSM (n = 186), median overall survival (OS) did not differ (NAC: 40 vs SF: 56 months; P = .210) but recurrence-free survival (RFS) was worse among patients who received NAC (14 vs 22 months; P = .007). NAC was independently associated with worse OS (hazards ratio [HR], 1.81; 95% confidence interval [CI], 1.03-3.18) and RFS (HR, 1.93; 95% CI, 1.25-2.99).

In this multi-institutional retrospective analysis of patients with peritoneal dissemination from appendiceal cancer, the use of NAC before CRS-HIPEC was associated with worse OS and RFS even after PSM and multivariable regression. Immediate surgery should be considered for patients with disease amenable to complete cytoreduction.