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CHARACTERISTICS AND OUTCOMES OF EXTERNAL REFERRAL PATIENTS UNDERGOING CYTOREDUCTIVE SURGERY AT AN INTERNATIONAL PERITONEAL SURFACE MALIGNANCY PROGRAM
Edward A. Joseph
*, Muhammad Muntazir Mehdi Khan, Gordon Hua, catherine lewis, Patrick Wagner, David Bartlett, Casey Allen
Surgical Oncology, Allegheny Health Network, Pittsburgh, PA
Introduction: Given the limited number of high-volume centers offering cytoreductive surgery (CRS) and heated intraperitoneal chemotherapy (HIPEC), patients often seek care outside their health systems. To understand the implications of care for external referral patients, we conducted a comprehensive assessment of an international peritoneal surface malignancy (PSM) referral program.
Methods: We analyzed patients with PSM treated at a high-volume PSM referral program from January 2022 to March 2024. Patients were categorized into two groups: in-system (IS), consisting of those referred from within our integrated network, and out-of-system (OOS), representing patients referred from outside our health system. Patient and disease characteristics, surgical outcomes, and institutional costs were compared between the two groups.
Results: We identified 171 patients who underwent CRS±HIPEC at our institution. The mean age was 56 ± 12 years, 57% were female, and 92% were White. The most common histological diagnoses included non-invasive appendiceal neoplasms (21%), adenocarcinoma of the appendix (32%), adenocarcinoma of the colon (21%), and ovarian carcinoma (8%). Overall, 59% (n=101) of patients were OOS. Compared to IS patients, OOS patients had a higher proportion of poorly differentiated adenocarcinoma of the appendix/colon (33% vs 17%, p=0.005), higher peritoneal cancer index scores, required longer operative times, and hospital stays (all p<0.050). There was no difference in completeness of cytoreduction (CC) scores, readmission rates, Clavien-Dindo complications, or 90-day mortality rates between IS and OOS patients (all p>0.050). OOS patients incurred higher direct institutional costs (p<0.001). Of all OOS patients, 72 (71%) were originally unable to achieve a complete cytoreduction at an outside institution (54 not offered surgery, 12 were aborted intraoperatively, 6 underwent incomplete cytoreduction). Of these, the majority subsequently achieved complete cytoreduction (85%, n=61) or surgical palliation (10%, n=7).
Conclusion: Compared to IS patients, OOS patients present with a higher disease burden, higher rate of high-grade tumor histology, require more extensive surgery, and incur longer hospital stays with higher costs of care. The majority of OOS patients previously deemed unresectable at outside institutions were able to achieve complete cytoreduction at a high-volume PSM referral program.
Table: Demographic and clinical characteristics of patients undergoing cytoreductive surgery at an international peritoneal surface malignancy program.
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