Characteristics and Outcomes of External Referral Patients Undergoing Cytoreductive Surgery at an International...

Peritoneal surface malignancy (PSM) patients often seek care outside their local health systems. Understanding the implications of care for these externally referred patients is critical for optimizing resource allocation and value-based care delivery.

Patients who underwent cytoreductive surgery ± heated intraperitoneal chemotherapy (CRS ± HIPEC) at an international PSM program between 2022 and 2024 were categorized as in-system (IS; referrals within our integrated network) or out-of-system (OOS; referrals from external institutions). Demographic, oncologic, surgical, and financial data were compared.

Among 171 patients (mean age: 56 ± 12 years; 57% female; 92% white), 59% (n = 101) were OOS. These patients had higher Peritoneal Carcinomatosis index (PCI) (18.5 [12.0-29.0] versus 13.0 [6.0-18.0]), longer operative time (518 [381-630] min versus 321 [214-490] min), and hospitalizations (14.0 [9.0-21.0] days versus 9.0 [6.0-15.0] days), all p < 0.050. There was no difference in completeness of cytoreduction (CC 0/1: 85.0% OOS versus 87.7% IS, p = 0.626), readmissions (20.8% OOS versus 15.7% IS, p = 0.403), or mortality (4.0% OOS versus 0.0% IS, p = 0.092). OOS patients incurred higher institutional costs (direct: $76,620 [$56,527-$99,072] versus $58,375 [$35,363-$82,635], p < 0.001; indirect: ($30,788 [$20,581-$40,037] versus $20,743 [$12,690-$35,887], p < 0.001). Notably, of 72 (71%) OOS patients previously deemed unresectable at outside institutions, 85% (n = 61) achieved complete and 10% (n = 7) received palliative cytoreduction.

OOS patients with PSM present with higher disease burden, require more extensive surgery, and incur higher costs. Yet, most OOS patients previously deemed unresectable were able to achieve complete cytoreduction at a high-volume PSM program.