Abstract
OBJECTIVES: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.