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.

Objective: The objective of this retrospective study is to develop a novel marker- ratio of serum CA 125 to peritoneal carcinomatous index(PCI) - to predict the response in women receiving neoadjuvant chemotherapy for newly diagnosed advanced epithelial ovarian cancer at our centre. 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. Only patietns with serous histology were chosen. Pre chemotherapy serum CA125 value was noted. Radiological PCI was calculated by reviewing the CECT films & reports of the patients. Patients were compared with the ratio of CA125 to radiological PCI and clinical & pathological response to neo adjuvant chemotherapy. All patients received standard doses of three weekly Paclitaxel and Carboplatin based chemotherapy. Based on the ratio of CA125 to PCI patients were divided into 2 groups – ratio more than 100 and less than 100. Results: A total of 34 were patients were found to meet the eligible criteria. Response assessment was done after 3 to 4 cycles of neoadjuvant chemotherapy. The overall response rate to neoadjuvant chemotherapy in patients in group 1 ( CA125/PCI ratio > 100) was significantly higher as compared to patients in group 2 (CA125/PCI ratio <100). Conclusion: In summary, CA 125 to PCI ratio is novel method to predict response to chemotherapy in advanced epithelial ovarian cancers. This value is a helpful measurement that allows the clinicians to measure the degree of chemosensitivity prior to cytoreductive surgery. This measures the inherent tumor biology and to aids in surgical decision making regarding the role and extent of cytoreduction as well as alternate systemic/local therapies.