Clinical characteristics of bowel mucosal invasion in epithelial ovarian cancer

Background Bowel mucosal invasion epithelial ovarian cancer (EOC) is classified as stage IVB disease. The reason for this classification remains unclear, and clinical data on bowel mucosal invasion in EOC should be investigated. Methods We retrospectively reviewed data from patients with stage IVB EOC who presented at our hospital with bowel mucosal invasion between January 2011 and September 2023. Patients with bowel mucosal invasion and other factors associated with IVB EOC were excluded from the study. The primary and secondary considerations were progression-free survival (PFS) and overall survival (OS), respectively. Results Two-hundred fifty-four patients were diagnosed with stage IVB EOC. Among these, 23 (9.1%) patients had bowel mucosal invasion, and 13 (5.1%) were diagnosed with stage IVB EOC based on bowel mucosal invasion alone. The median follow-up period was 40.5 months (range, 14.9–81.6 months). PDS was performed in nine patients (69.2%), NAC-IDS in four (30.8%), and R0 resection was achieved in all of the 13 patients without other stage IVB-related factors. Among those patients, the 3-year PFS and OS rates were 54.9% and 82.1%, respectively. Conclusion We have shown that in cases of bowel mucosal invasion, complete resection may be possible and the prognosis of these patients may be better than in the general population at stage IVB. Based on these observations, we believe that bowel mucosal invasion by itself is not a potential prognostic factor for stage IVB ovarian cancer.