Preoperative systemic chemotherapy does not benefit for appendiceal pseudomyxoma peritonei.

Background: Pseudomyxoma peritonei (PMP) is a clinically malignant tumour syndrome mainly derived from mucin-producing appendiceal tumours. This study aimed to explore the effect of preoperative systemic chemotherapy (PSC) before cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC) on the safety and postoperative survival in patients with appendiceal PMP.

Methods: We performed a retrospective analysis including consecutive patients with PMP undergoing primary surgery between January, 2008 and December, 2019 in Aerospace Center Hospital. The clinical data and postoperative survival were compared between PSC group and non-PSC group.

Results: Seven hundred and fifty patients were included in the study. Significant differences were found between PSC group and non-PSC group on clinicopathological data and perioperative outcomes and the independent risk factor of serious complications was blood loss >1000 mL (P = 0.026). Shorter median overall survival (OS) was found (42 months, 95% CI 31.9-52.1) in PSC group than that (67 months 95% CI 44.5-89.5) in non-PSC group. In the stratified study with PCI < 20, CC 0/1 and low-grade pathological subtype, the OS from non-PSC group was significantly better than that in PSC group (log rank P-values are <0.001, 0.006 and <0.001, respectively). Multivariate survival analysis showed that CC 0/1, HIPEC, PCI < 20 and low-grade pathological subtype were the independent prognostic factors for better OS.

Conclusions: PSC does not increase the risk of major perioperative complications in patients with appendiceal PMP, but it also does not bring postoperative survival benefits to patients either.