Abstract 6520: Clinical verification oftherelationship betweenserum lipid metabolism andtumor immune microenvironment inpostmenopausal hormone receptor-positive/HER2-negative breast cancer patients

Abstract

Abstract Background: Recently, some basic research has reported that the tumor immune microenvironment (TIME) is related to the therapeutic efficacy and prognosis of breast cancer patients, and that the regulation of metabolism can affect TIME and enhance antitumor immunity. Suppression of aromatase expression from adipose tissue is the standard adjuvant endocrine therapy for postmenopausal hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative breast cancer, but few studies have examined the impact of controlling lipid metabolism on TIME and cancer prognosis. Materials and Methods: Except for patients with ductal carcinoma in situ, 531 postmenopausal HR-positive/HER2-negative breast cancer patients treated with curative surgery between 2011 and 2017 were examined. Serum lipid levels and systemic immune-related markers were evaluated by blood samples, and tumor-infiltrating lymphocytes (TILs) in cancer tissue samples were investigated by immunohistochemistry. We also examined the relationship between lipid metabolism, TIME, and prognosis, respectively. Results: Good serum lipid control group was significantly correlated with low neutrophil- to-lymphocyte ratio (NLR) (p = 0.024) and high TILs (p = 0.039). The median follow-up time for the assessment of prognosis was 5.5 years, and 67 patients had recurrence. Only patients treated with aromatase inhibitor as adjuvant endocrine therapy showed significantly better recurrence-free survival (RFS) in the good lipid control group (p = 0.025, log-rank). Also, multivariate analyses showed that good serum lipid control was an independent prognostic factor for recurrence (HRs = 4.722, 95%CI: 1.006-22.161, p = 0.049). Patients with high CD8/FOXP3 ratio (CFR) had significantly better RFS (p=0.027, log-rank) and tended to have good lipid control. Conclusions: Good control of serum lipid metabolism may inhibit the acquisition of resistance to endocrine therapy by improving TIME and induce favorable outcome in postmenopausal HR-positive/HER2-negative breast cancer patients. Citation Format: Wataru Goto, Hanae Matsuda, Saeko Henmi, Mariko Nishikawa, Asuka Kouchi, Rika Kouhashi, Akimichi Yabumoto, Koji Takada, Yukie Tauchi, Kana Ogisawa, Tamami Morisaki, Shinichiro Kashiwagi. Clinical verification oftherelationship betweenserum lipid metabolism andtumor immune microenvironment inpostmenopausal hormone receptor-positive/HER2-negative breast cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6520.