HALF LIFE OF CA 125 AS A MARKER OF RESPONSE TO NEO ADJUVANT CHEMOTHERAPY AND PREDICTIVE MODEL OF SURGICAL OUTCOME IN ADVANCED EPITHELIAL OVARIAN CANCER- A SINGLE INSTITUITIONAL STUDY.

Abstract

Objective: The objective of this retrospective study is to identify the elimination half life of CA 125 biomarker in women receiving neoadjuvant chemotherapy for newly diagnosed advanced epithelial ovarian cancer at our centre and develop it as a surrogate marker of response to chemotherapy. Methods: Medical records of women who were newly diagnosed with inoperable advanced ovarian cancer stages III and IV at our centre were selected. Only people with completely documented records in the years 2017 & 2018 were selected. Clinical information on age, menopausal status, BMI, radiological PCI, stage, histology, chemotherapy drugs used, CA 125 levels before and after neoadjuvant chemotherapy were noted and information analysed. Only 40 patients were identified meeting all required criteria. The patients were divided into 3 sets based on CA 125 elimination half life group 1(t ½ < 10 days), group 2 (t ½ 10- 20 days) and group 3 (t ½ > 20 days). The base line characters and outcomes of surgery and pathological responses were compared between these groups. Results: Optimal cytoredcution was possible in 19/21(90.4%) patients in group 1, 6/10(60%) in group 2 & 2/9(22.2%) in group 3. Clinical complete response was found in 12/21 (57.1%), 2/10(20%) & 0/9(0%) respectively. Progressive disease was noted in 4/9(44%) of group 3 patients. There was striking differences between the groups with respect to clinical and pathological response. Conclusion: In summary, CA 125 elimination half life measurement is a reproducible tool that can be used to assess chemotherapy sensitivity in patients with newly diagnosed advanced ovarian cancer following neoadjuvant chemotherapy. The CA 125 half life value is a helpful measurement that allows the clinicians to measure the degree of chemosensitivity prior to cytoreductive surgery.