Histopathological Subtype and Cancer Stem Cell Marker Expression in Advanced Epithelial Ovarian Cancer: A Two-Year Progression-Free Survival Study

Background: Late detection and significant recurrence rates make epithelial ovarian cancer (EOC) one of the deadliest gynecologic cancers. Cancer stem cells (CSCs) have been associated with chemoresistance and relapse. However, their prognostic significance remains uncertain. This study examined CSC marker expression in advanced EOC with 2-year progression-free survival (PFS) and the predictive significance of type I/type II classification in histological subtypes. Methods: We performed an ambispective cohort study of 114 women with advanced EOC who had undergone optimal cytoreductive surgery and standard platinum-based chemotherapy. Expression of CD24, CD44, CD117, CD133, and aldehyde dehydrogenase (ALDH) was studied by immunohistochemistry. PFS was evaluated using Kaplan–Meier methods and correlations were assessed using chi-square or Fisher’s exact test. The predictive value was assessed using receiver operating characteristic (ROC) analysis. Independent predictors of PFS were identified by multivariate Cox regression analysis. Results: Most patients had stage III disease (60.5%) and were 40–59 years old (65.8%) significantly associated with poor survival (P < 0.001). Type II cancers had significantly worse 2-year PFS compared to type I tumors (21.3% vs. 44.8%, P = 0.008). None of the single CSC markers were significantly associated with PFS in univariate analysis (all P > 0.05) and had poor discrimination in ROC analysis. The combined assessment of CSC markers and histological classification further improved the prognostic stratification and was significantly associated with PFS (P < 0.05). In multivariate analysis, age, tumor stage, and histology type were independent predictors of PFS. Conclusion: Expression of CSC markers alone is not an independent predictor of 2-year PFS in advanced EOC. Its prognostic relevance is modulated by tumor histology as type I/type II provides a stronger and more consistent prognostic stratification.