What is the optimal strategy to confirm the diagnosis of epithelial ovarian carcinoma (EOC) prior to neoadjuvant chemotherapy (NAC)?

Abstract

5511 Background: NAC has been increasingly utilized in clinical practice yet no standard diagnostic strategy has been defined for EOC prior to the administration of NAC. We reviewed the diagnostic process for patients receiving NAC at our centre to determine if an optimal diagnostic strategy could be determined. Methods: A retrospective chart review of all patients known to receive NAC followed by cytoreductive surgery for presumed EOC between 1994 and 2007 was performed. Diagnostic strategies were defined as histology, cytology, and clinical. Performance of these strategies in predicting final pathology, based on expert pathology review of surgery specimens, was compared using Fisher's exact test. Results: 152 patients were included. Initial diagnosis was made on the basis of: cytology (paracentesis/thoracentesis)- 89 (59%); percutaneous biopsy- 40 (26%), radiology and CA-125–18 (12%), surgical biopsy -5 (3%). The final diagnosis was consistent with invasive EOC in 145 patients (95%). The remaining 7 were ovarian LMP (4), ovarian carcinosarcoma (1), endometrial serous cancer (1), and GI tumor (1). The diagnostic accuracies of the 3 strategies differed: histology (43/45), cytology (87/89), and clinical (15/18), p = 0.039. 17% of patients had an alternate final diagnosis when clinical parameters were the only basis for the diagnosis of EOC prior to NAC. A specific EOC subtype was identified pre-op in 82 patients (histology-31 cases, cytology-51 cases). Subtype differed between pre- and post-treatment samples in 13% of histology and 8% of cytology cases. Conclusions: Diagnosis of EOC based on cytology or histology-based strategies are superior to clinical factors alone. Even in a centre with trained gynecologic cytopathologists, cytology and biopsy strategies preclude accurate subtype diagnosis in a significant number of patients. These data are important for clinical practice and the design of future clinical trials. No significant financial relationships to disclose.