Sclerosing Encapsulating Peritonitis Is More Common Following Repeat Hyperthermic Intraperitoneal Chemotherapy

Introduction: Sclerosing encapsulating peritonitis (SEP) is a rare complication of cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC). The purpose of this study is to determine the incidence and risk factors for developing SEP, as well as to characterize the clinical presentation, diagnosis, and management outcomes of SEP. Methods: This study was conducted at the University of Colorado Anschutz in Aurora, Colorado, a tertiary referral center for peritoneal surface malignancies. Patients undergoing CRS with or without HIPEC were identified from our retrospective CRS/HIPEC database. Patients with clinical, operative, and/or radiologic features of SEP were identified, and their clinical parameters were compared with those of patients without these findings. Results: Between January 1, 2017, and June 1, 2025, 500 patients underwent CRS with (n = 388) or without HIPEC (n = 112). Six patients developed the typical clinical and radiologic findings of SEP, including chronic or recurring small bowel obstruction, postprandial abdominal pain, vomiting, weight loss, and persistent small bowel dilation on CT scans. The median time from the most recent CRS/HIPEC to presentation with SEP was 5.5 months (range 2-11). Five of six patients underwent laparotomy, with four receiving surgical resection of the encapsulating fibrous rind. Symptoms resolved in four patients with no recurrence. One patient developed a chronic enterocutaneous fistula and is total parenteral nutrition (TPN) dependent. One patient opted for observation and has ongoing symptoms of SEP. SEP was significantly more common (p < 0.05) in patients following repeat (>2) HIPEC (3/53, 5.7%) than an initial HIPEC (3/335, 0.9%). Conclusions: SEP is a rare complication of HIPEC that presents within a year of HIPEC with chronic or recurrent bowel obstruction secondary to adhesions encasing the small bowel. The risk of SEP increases with repeat CRS/HIPEC.