Vaginal Tumor Cell Exfoliation in Cervical and Endometrial Cancer: A Comparative Washing Cytology Study with Implications for Minimally Invasive Surgery.

Background/Objectives: Minimally invasive surgery (MIS) is widely used for gynecologic malignancies, but the LACC trial reported significantly worse survival in early-stage cervical cancer compared with open surgery, raising concerns about its oncologic safety. Tumor cell spillage during intracorporeal colpotomy in the Trendelenburg position has been proposed as a potential mechanism underlying these findings. This study aimed to assess the presence of tumor cells exfoliated into the vaginal cavity in cervical and endometrial cancers using vaginal washing cytology. Methods: We retrospectively analyzed patients newly diagnosed with cervical or endometrial cancer between June 2021 and February 2025. Vaginal washing cytology was performed before treatment and interpreted. Chi-square or Fisher's exact tests and multivariate logistic regression were used to identify factors associated with positive cytology. Results: Positive cytology detected more often in cervical than in endometrial cancer (all stages: 33.3% [12/36] vs. 6.5% [3/46], p = 0.002; early stage: 24.0% [6/25] vs. 0% [0/38], p = 0.003). Multivariate analysis confirmed cervical cancer (OR 14.24, 95% CI 1.83-110.89, p = 0.011) and FIGO stage III-IV (OR 9.53, 95% CI 2.08-43.61, p = 0.004) as independent predictors. Conclusions: Tumor cells exfoliated into the vagina were significantly more frequent in cervical cancer, supporting a mechanism by which intracorporeal colpotomy may allow peritoneal entry. Further studies should reassess MIS for early-stage cervical cancer, considering transvaginal colpotomy in the horizontal position.