Neoadjuvant chemotherapy alters the balance of effector to suppressor immune cells in advanced ovarian cancer.

BACKGROUND: At diagnosis, tumor-infiltrating lymphocytes (TILs) are prognostic in epithelial ovarian cancer (EOC). We recently demonstrated that neoadjuvant chemotherapy (NACT) significantly increased stromal TILs. Here, we investigated the impact of NACT on immune subpopulations with a particular focus on the balance of immune-reactive to tolerant subpopulations. MATERIALS AND METHODS: Tissue microarrays of EOC (145 pre-NACT, 139 post-NACT) were analyzed for CD3+, CD8+, FOXP3+, CD68+, and CD163+ by immunohistochemistry and CD4+ cells from deduction. Stromal TILs scored as percentage of stromal area, while intra-epithelial TILs scored as number of TILs in contact with tumor cells/HPF. Differences were evaluated by Wilcoxon or Chi square tests, Wilcoxon signed-rank for paired analyses, and cox model for PFS and OS. RESULTS: NACT significantly increased stromal CD3+ (p = 0.003) and CD8+ (p = 0.001) and intra-epithelial CD8+ (p = 0.022) and CD68+ (p = 0.0003) infiltration in unmatched samples and among paired samples for stromal CD3+ and CD8+. Neither CD3+, CD8+, CD4+, and CD68+ nor CD163+ expression correlated with outcome at diagnosis or post NACT. Using median value as a cut-off, high stromal CD8+/FOXP3+ ratio (HR = 0.59; p = 0.017) and high stromal CD3+/FOXP3+ ratio post NACT were associated with prolonged PFS (p = 0.0226). The more the balance shifted in favor of effector versus regulatory TILs, the better the survival. Similarly, high CD68+/CD163+ ratio post NACT improved PFS (p = 0.0445). CONCLUSION: NACT has a significant impact on the balance of immune-reactive to immune-tolerant subpopulations and a high ratio of CD8+/FOXP3+, CD3+/FOXP3+, and CD68+/CD163+ post NACT was significantly associated with improved outcomes. Whether this could select patients for immunotherapy in the post-operative setting should be investigated.

Impact of neoadjuvant chemotherapy on the immune microenvironment in advanced epithelial ovarian cancer: Prognostic and therapeutic implications.

Over the last decade, increasing evidence highlights the role of the host immune system in the control of tumor growth and the prognostic implications of tumor infiltrating lymphocytes (TILs) in ovarian cancer. Most data support a better prognosis with accumulation of CD3+ and CD8 + TILs and a poor outcome associated with increased regulatory T cells. However, only a small number of studies have focused on the effect of neoadjuvant chemotherapy (NACT) on the tumor immune microenvironment. This review will provide an update on the prognostic value of TIL subpopulations at diagnosis and a comprehensive overview of the recent studies evaluating the impact of neoadjuvant chemotherapy on TILs and their relationship to clinical outcome in advanced ovarian cancer. This information could help in future investigations of immunotherapy as maintenance following primary treatment.