# Long-term outcomes of pseudomyxoma peritonei after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy and its relevant risk factors in China: a retrospective study

## TL;DR

This study examines long-term survival and risk factors for pseudomyxoma peritonei patients treated with surgery and chemotherapy in China.

## Contribution

The study identifies key prognostic factors in a large Chinese cohort of PMP patients treated with CRS-HIPEC.

## Key findings

- Median survival was 56 months for overall survival and 45 months for event-free survival.
- Preoperative tumor markers, CC-score, and high-grade PMP were independent predictors of poorer outcomes.
- Intraoperative hypotension and hyperthermia did not affect survival or event-free survival.

## Abstract

Pseudomyxoma peritonei (PMP), generally spread of low grade appendiceal mucinous neoplasm (mucinous appendix neoplasms) into the abdominal cavity, is conventionally treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC). Prognostic factors of small cohort sizes remain incomplete and conflicting. This large-scale study aimed to characterize long-term survival outcomes and identify prognostic factors in PMP patients following CRS-HIPEC.

We conducted a retrospective cohort study of 432 consecutive PMP patients treated with CRS-HIPEC at Aerospace Center Hospital (Beijing, China) from June 2014 to December 2020. Overall survival (OS) served as the primary endpoint, with event-free survival (EFS) as the secondary endpoint. Multivariable Cox proportional hazards models were employed to identify independent prognostic factors.

With median survival durations of 56 months (OS) and 45 months (EFS), cumulative mortality and event incidence reached 21.4% and 32.4%, respectively. Independent predictors for poorer OS included: preoperative raised tumor markers (hazard ratio [HR] = 4.90–10.20; 95% confidence interval [95% CI]: 1.11–46.67; P < 0.05), completeness of cytoreduction (CC) score (HR = 3.37–9.41; 95% CI: 1.05–16.37; P < 0.05), and high-grade PMP (HR = 1.80; 95% CI: 1.10, 2.93; P = 0.019). EFS was significantly associated with preoperative Barthel index (HR = 0.86; 95% CI: 0.74, 0.98; P = 0.019) in addition to the aforementioned factors. Intraoperative hypotension and hyperthermia were not associated with both OS and EFS.

Key factors impacting outcomes of patients with PMP of mucinous appendix neoplasms included preoperative elevated tumor markers, Barthel index, CC-score, and the PMP histology, without intraoperative hypotension and hyperthermia.