Surgical management of peritoneal metastases from appendix and colon cancer in patients with inflammatory bowel disease

<h2>Abstract</h2><h3>Background</h3> Inflammatory bowel disease (IBD) may compromise outcomes of cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) for peritoneal metastases (PM) from appendix/colon cancer. We evaluated CRS/HIPEC outcomes in patients with concurrent IBD. <h3>Methods</h3> A matched cohort study using a prospective institutional CRS/HIPEC database (1998–2023) included appendix/colon cancer patients with PM. We matched IBD patients to IBD-free controls in a 1:5 ratio with nearest-neighbor propensity score for sex, age, and peritoneal cancer index (PCI), and exact matching for prior CRS/HIPEC and primary tumor. Perioperative variables, including Clavien-Dindo 90-day complications, were compared. Kaplan-Meier overall (OS) and progression-free survival (PFS) were compared using stratified Cox regression. <h3>Results</h3> Of 605 CRS/HIPECs for appendix/colon cancer, 14 (2.3%) had concurrent Crohn's disease (n = 6) or ulcerative colitis (n = 8). Seventy IBD-free controls were matched. Nine (64.7%) IBD patients had an appendix primary. Complete cytoreduction (CC-0/1) was achieved in 10 (71.4%) IBD and 57 (81.4%) IBD-free patients (p = 0.468). IBD vs IBD-free patients tended to have more grade-III/IV complications (35.7% [n = 5] vs 15.7% [n = 11], p = 0.082) and had a higher rate of severe nausea/vomiting (35.7% vs 4.3 %, p < 0.001) and diarrhea (28.6% vs 8.6%, p = 0.035). Rates of anastomotic leak (7.1% [n = 1] vs 1.4% [n = 1], p = 0.200) and intraabdominal infections (7.1% [n = 1] vs 2.9% [n = 2], p = 0.430) were similar for IBD vs IBD-free, respectively. IBD did not affect OS (HR [95% CI]: 1.1 [0.4, 2.9]) or PFS (HR [95% CI]: 1.2 [0.4, 3.9]). <h3>Conclusion</h3> IBD is associated with a higher rate of gastrointestinal complications after CRS/HIPEC for appendix/colon cancer; however, it does not affect OS or PFS.