Ileocecal and Small Bowel Involvement Are Independently Associated with Inferior Survival Despite Complete Cytoreduction in FIGO IIIC–IV Tubo-Ovarian and Primary Peritoneal Carcinoma

BACKGROUND: Complete macroscopic tumor resection is the strongest prognostic factor in advanced epithelial tubo-ovarian and primary peritoneal cancer, yet benefit from maximum-effort cytoreductive surgery may vary with tumor distribution and site-specific resections. We aimed to identify predictors of long-term survival, considering postoperative morbidity, to inform preoperative stratification. PATIENTS AND METHODS: This study had a retrospective single-center cohort of 302 all-comers patients with International Federation of Gynecology and Obstetrics/American Joint Committee on Cancer (FIGO/AJCC) IIIC-IV epithelial tubo-ovarian or primary peritoneal cancer undergoing maximum-effort cytoreductive surgery in a European Society of Gynecological Oncology (ESGO)-certified high-volume tertiary referral center (2006-2021). Major complications (Clavien-Dindo ≥ IIIb) were analyzed using multivariable logistic regression; progression-free and overall survival (PFS/OS) using Cox regression. Subgroup analyses explored site-specific bowel resections. RESULTS: Complete resection was achieved in 259 (85.8%) patients, requiring high surgical complexity in 221 (73.2%, Surgical Complexity Score ≥ 8). Intestinal segment resections were performed in 71.5% of patients, including ileocecal resection in 24.5%. Large bowel resection (OR 2.708, p = 0.002) significantly increased major postoperative morbidity. Anastomotic leakage occurred in 6.0%, independent of transitory stoma formation (p = 0.759). Small bowel resection independently predicted impaired long-term survival (3-year OS 31.8% versus 57.0%, p < 0.001). Ileocecal resections were associated with poorest outcome (3-year OS 24.2%, p < 0.001). Complete macroscopic resection remained prognostically beneficial. Neoadjuvant chemotherapy (13.9%) and high surgical complexity did not negatively affect long-term survival. CONCLUSIONS: Ileocecal and small bowel involvement are independently associated with inferior survival despite complete cytoreduction in FIGO IIIC-IV disease. These findings support preoperative triage and counseling by the multidisciplinary tumor board, with selective consideration of primary systemic therapy with planned interval cytoreduction for extensive small bowel/ileocecal disease, particularly in frail or complex patients.