217 The impact of chemotherapy response score and lymphocytic infiltration in patients with ovarian cancer treated with neoadjuvant chemotherapy

Introduction/Background* Neoadjuvant chemotherapy (NACT) followed by interval debulking surgery (IDS) represents an alternative approach to primary debulking for the management of advanced epithelial ovarian cancer (EOC) with comparable survival outcomes. Histopathologic examination of the IDS specimens and the evaluation of Chemotherapy Response Score (CRS) have been proposed as significant markers of response to NACT. The aim of the prsent study was to evaluate the prognostic significance of CRS in OC patients treated with NACT. Methodology A single institution retrospective analysis of patients with OC stage ≥III who were selected to receive NACT from 2011 to 2018 was performed. Omental and ovarian samples were assessed for the evaluation of CRS according to International Collaboration on Cancer Reporting (ICCR) recommendation. Lymphocytic infiltration, presence of necrosis and mitotic index were also assessed. Result(s)* The final analysis included a total of 60 patients with median age of 65 years at diagnosis. Omentum and ovarian samples of the included patients revealed a CRS 3 in 20 and 10 patients, respectively. Patients with CRS3 at omentum had significantly prolonged median progression free survival (PFS) compared to CRS1 and CRS2 (19 vs 10 vs 15 months, respectively, p=0.002), while no difference was observed in the respective OS among the groups (42 vs 28 vs 32.3 months, respectively). Lymphocytic infiltration in pre-treatment biopsies was related to improved PFS and OS (log-rank p =0.01 and p=0.015, respectively). No effect on either PFS or OS was observed in patients who received bevacizumab post-IDS, while in patients with lymphocytic infiltration bevacizumab negatively affected PFS. Conclusion* CRS seems to play a key role in the prediction of the postoperative course of EOC patients who received NACT and IDS. However, further studies are warranted to decipher the exact role of CRS and lymphocytic infiltration so as to personalize the treatment of EOC patients.