Clinical Implications of Cytology Negative Pleural Effusion in Advanced Stage Epithelial Ovarian Cancer—Insights from a Tertiary Cancer Center in Northeast India

Pleural effusion is a decisive factor in advanced-stage ovarian cancer. The presence of malignant cells in pleural effusions in women with ovarian cancer is accepted as a poor prognostic factor. It is included in the International Federation of Gynecology and Obstetrics (FIGO) stage IVA. Still, the literature does not explain and prognoses the importance of cytology-negative pleural effusion (CNPE) in women with ovarian cancer. It is a retrospective study conducted in a tertiary cancer center. All advanced staged ovarian cancer patients with pleural effusion registered between January 2020 and December 2021 were included, and the control group consisted of all stage IIIC disease with no pleural effusion during the same duration. Survival analysis was done in these three groups-cytology-positive pleural effusion (CPPE), cytology-negative pleural effusion (CNPE), and no pleural effusion (NPE). In total, 117 patients with advanced-stage ovarian cancer, fulfilling the eligibility criteria, completed their treatment during the study period. Retrospective data was collected from hospital records, and survival analysis was done using SPSS 29.0. We included only those patients who had pleural fluid analyzed by a pathologist. During the study period, we found that 13 (11%) were CPPE, 23 (19.3%) were CNPE, and 81 (68%) were NPE. CNPE patients had poor progression-free survival (PFS) and overall survival (OS) compared to NPE patients, although both groups were labeled stage IIIC. These findings underscore the importance of cytology-negative pleural effusion in ovarian cancer prognosis, providing valuable insights for clinical practice. Patients with cytology-positive pleural effusion had the worst prognoses. However, CNPE patients labeled as stage IIIC had poor outcomes compared to NPE stage IIIC patients. So, based on our comprehensive study, we recommend a video thoracoscopic analysis of all patients with CNPE to correctly stage these patients, further modify their treatment accordingly, and improve their outcomes.