Peritoneal cytology as an indicator of disease in patients with residual ovarian carcinoma.

Cytologic assessment of peritoneal washings or ascites in ovarian cancer patients has been suggested as a method of evaluating response to therapy or disease status, although the accuracy of this technique has not been clearly established. Ascitic fluid or peritoneal washings were obtained during 96 reassessment laparotomies that were biopsy-positive for residual intraperitoneal ovarian cancer. Cytologic studies done on these samples failed to detect malignant cells in 66% of the cases with gross residual disease and 78% of the cases with only microscopic residual disease on biopsy. The accuracy of peritoneal cytology in detecting residual ovarian cancer was unrelated to residual tumor size, original clinical stage, histologic tumor grade, and tumor cell type. Examination of ascitic fluid found at the time of surgery was somewhat more reliable than assessment of peritoneal washings, although this difference was of borderline statistical significance. Peritoneal cytology cannot reliably detect residual ovarian cancer after initial treatment with surgery and chemotherapy. Negative peritoneal cytology is frequently seen in the presence of gross residual tumor.