Clinical characteristics of bowel mucosal invasion in epithelial ovarian cancer

Bowel mucosal invasion in epithelial ovarian cancer (EOC) is classified as stage IVB disease. However, the reason for this classification remains unclear, and the clinical outcomes of bowel mucosal invasion in EOC warrant further investigation. Therefore, we aimed to examine patients with EOC presenting with bowel mucosal invasion and evaluate the validity of the current classification.

We retrospectively reviewed data from patients with stage IVB EOC who presented with bowel mucosal invasion at our hospital between January 2015 and September 2023. Patients with bowel mucosal invasion and other factors associated with stage IVB EOC were excluded. The primary and secondary endpoints were progression-free survival (PFS) and overall survival (OS), respectively.

Among 226 patients diagnosed with stage IVB EOC, 22 (9.7%) exhibited bowel mucosal invasion and 13 (5.8%) were diagnosed with stage IVB EOC based solely on the presence of bowel mucosal invasion. The median follow-up period was 40.5 months (range, 14.9-81.6 months). Primary debulking surgery was performed in nine patients (69.2%) and neoadjuvant chemotherapy-interval debulking surgery in four (30.8%). Complete resection was achieved in all 13 patients without other stage IVB-related factors. Among them, the 3-year PFS and OS rates were 54.9% and 82.1%, respectively.

In cases of bowel mucosal invasion, complete resection appears feasible and may be associated with a more favorable prognosis compared with that of the overall stage IVB population. Therefore, bowel mucosal invasion alone may not represent a potential prognostic factor for stage IVB ovarian cancer.