1018P - Tumour-infiltrating lymphocytes (TILs) in patients with epithelial ovarian cancer undergoing neoadjuvant chemotherapy: A retrospective study

Abstract

BackgroundThe role of the adaptive immune response in tumors has been widely explored.TILs are related with a better survival in several tumors. In ephitelial ovarian cancer (EOC) there are few data focusing on the effects of neoadjuvant chemotherapy (NACT) on T-cell infiltration, with controversial results.TILs may represent a prognostic and predictive biomarker and may have a role in selecting patients for immunotherapy. MethodsWe retrospectively evaluated 131 patients with stage IIIC-IV EOC who received NACT with platinum and taxane, interval debulking surgery (IDS) and chemotherapy post IDS.14 patients were excluded due to complete response. Stromal and Intratumoral TILs (sTILs-iTILs) were evaluated in tumor biopsies (pre NACT samples) and on residual disease post surgery (post NACT samples), using the criteria defined by the International TILs Working Group. The objective of the study was evaluating whether NACT could determine an increase T-cell infiltration with a consequent positive effect on outcome. ResultsMedian follow up was 70.25 months.OS at 2 and 5 years were 68.6% (95%CI: 61.0%-77.1%) and 26.8% (95%CI:19.5%-36.8%) respectively.In the final analysis 50 patients were excluded due to the lack of suitable pre NACT samples.There was no association between sTILS or iTILs values assessed on pre and/or post NACT samples with OS (HR=0.99; HR=1.01 respectively) and PFS (HR=0.99; HR=1.002 respectively). However, investigating the difference of sTILs between post (median 12; IQR 6-20) and pre NACT samples (median 7; IQR 3.25-17), we found that an increase in sTILs in post NACT compared to pre NACT samples was associated with reduced mortality risk (HR=0.71; 95% CI: 0.50-1.00 p=0.05).Furthermore a no-linear association between the difference between post and preNACT iTILs and OS was detected (p=0.11). ConclusionsThese findings, although limited by the small sample size and the retrospective nature of this analysis, suggest a possible role of TILs detected in residual tumor after NACT as prognostic biomarker in EOC. Further data are needed in order to confirm the role of TILs after NACT and their possible relevance to predict efficacy of immunotherapeutic strategies in this setting. Legal entity responsible for the studyNicoletta Colombo, Sara Giovannoni. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.