Not many observational studies on the prognostic role of hyperthermic intraperitoneal chemotherapy (HIPEC) in pseudomyxoma peritonei (PMP) have been conducted. This study aims to investigate the outcomes after cytoreductive surgery (CRS) and HIPEC and compare them with CRS alone in patients with PMP.

This cohort study included a total of 1,924 patients with histologically confirmed PMP as a result of appendiceal mucinous neoplasm. The patients eligible for the study were treated with CRS with or without HIPEC. Researchers applied inverse probability treatment weights based on the propensity score for HIPEC treatment to balance the comparisons. The outcomes of the study were overall survival, severe morbidity, and 30-day and 90-day mortality.

The findings suggested that patients with CRS alone were older, had less lymph node involvement, had higher proportions of high-grade disease, had received more preoperative systematic chemotherapy. It was found that HIPEC was not associated with an increased risk of worse surgical outcomes apart from mitomycin, which had higher odds of morbidity. Furthermore, the findings revealed that HIPEC was associated with better overall survival in all subsets.

The research concluded that HIPEC was associated with better overall survival when given in combination with CRS for PMP and also showed a positive safety profile.