Ovarian cancer: Age, prognosis, and biologic underpinnings.

e17555 Background: The prognosis of ovarian cancer worsens markedly with age. Yet few data are available to explain this phenomenon. Two hypotheses can be made. Changes in pharmacokinetics (PK) and treatment tolerance limit the dosing of chemotherapy, and/or changes in tumor and host-tumor biology limit treatment efficacy. Objective:To identify PK, body composition, and biologic changes with age that may impact prognosis. We reported PK findings in a previous abstract (Extermann et al., ASCO 2021) In this abstract we focus on the biologic findings. Methods: We conducted a prospective cohort study of women with stage III/IV high-grade serous ovarian cancers treated with neoadjuvant intravenous carboplatin (C) AUC 5 every 3 weeks and paclitaxel (P) dosed either weekly at 80 mg/m2 or every 3 weeks at 175 mg/m2. Body composition was assessed using baseline CT scans at the L3 level. Pre- and post-chemotherapy plasma samples were assayed by ELISA for CRP, IL-6, TNF alpha, TNF-receptor 1 and 2, d-dimers, vitamins B12 and D, methylmalonic acid, and cortisol levels. Tissue samples pre- and post-chemotherapy were analyzed for gene expression, gene methylation, and immunohistochemistry for inflammatory markers and senescence. Toxicity was assessed as first cycle nadir ANC and G4 hematologic (H) or grade 3-4 non-hematologic (NH) toxicity by CTCAE 4.0 criteria over a 3 cycles follow-up. The correlation between continuous measures was assessed by Spearman correlation coefficient, and the association with toxicity was evaluated by Wilcoxon rank sum test. The association with relapse-free survival (RFS) and overall survival (OS) was calculated by Log-rank and Cox regression analyzes. Results: Seventeen patients, ages 38 to 86 (median 61) were eligible, 14 underwent surgery. Treatment delivery was high with a median relative dose intensity of 100%. The mean percentage of senescent cells (CAV-1 +) was 49.5% in the stroma, vs 12.8% in the tumor (p < 0.001) prechemotherapy, and 15.7% in the stroma vs 21.4% in the tumor post-chemotherapy (pre-post stroma p < 0.01). The percentage of PD-L1 positive cells and CTLA-4 positive cells was very low: mean < 1% both pre-and post-chemotherapy. The results from gene expression and methylation showed an increase in the inflammatory pathways and a decrease in the apoptosis pathways over time. Vitamin D levels decreased with age. Prechemotherapy CD8 percentage in the stroma and post chemotherapy d-dimers were associated with RFS. Conclusions: Neoadjuvant treatment delivery was high in an academic setting. Our results provide insights in the underexplored area of biologic response to chemotherapy in patients with ovarian cancer. Although our results did not provide clear candidates to explain the worsening of prognosis with age, they offer clues to develop future research on this issue.