Long-term outcomes following cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for pseudomyxoma peritonei: a 15-year national referral centre experience
Rok Petric, Gasper PilkoAbstract
Background
Pseudomyxoma peritonei (PMP) is a rare peritoneal malignancy most commonly originating from appendiceal mucinous neoplasms. Cytoreductive surgery (CRS) combined with has become the standard treatment for selected patients; however, evidence is largely based on retrospective single-centre series. We report the 15-year experience of the Slovenian National Referral Centre and evaluate long-term survival and prognostic factors following CRS and hyperthermic intraperitoneal chemotherapy (HIPEC).
Patients and methods
This retrospective study included all consecutive patients who underwent CRS and HIPEC for PMP between 2009 and 2024. Clinical, pathological, operative and follow-up data were prospectively collected and retrospectively analysed. Overall survival (OS) was the primary endpoint, while disease-free survival (DFS), postoperative morbidity and prognostic factors were secondary endpoints. Survival was analysed using the Kaplan-Meier method. Prognostic factors were evaluated using univariate and multivariate Cox regression analyses.
Results
Thirty-seven patients underwent CRS and HIPEC during the study period. The mean Peritoneal Cancer Index (PCI) was 17.2, and complete cytoreduction (CC-0/1) was achieved in 34 patients (91.9%). Major postoperative complications (Clavien-Dindo grade III–IV) occurred in seven patients (18.9%), while no 30-day postoperative mortality was observed. After a median follow-up of 68 months, the estimated 5-year and 10-year overall survival rates were 91.9% and 83.7%, respectively. Patients with a PCI ≤12 demonstrated significantly better overall survival than those with a PCI > 12 (log-rank p = 0.028). Multivariable analysis identified achievement of complete cytoreduction (CC-0/1) and elevated preoperative Carbohydrate Antigen 19-9 (CA19-9) as independent prognostic factors for overall survival.
Conclusions
CRS combined with HIPEC provides excellent long-term oncological outcomes with acceptable morbidity for patients with PMP when performed in a specialized national referral centre. Complete cytoreduction remains the principal determinant of survival, while preoperative CA19-9 provides additional prognostic information. These findings support continued centralization of PMP treatment for this rare disease.