Prognostic Value of Tertiary Lymphoid Structures in Epithelial Ovarian Carcinoma

Background/Aim: Tertiary lymphoid structures (TLS) have become the focus of antitumor immunity. However, the prognostic significance of TLS in epithelial ovarian cancer (EOC) treated with primary debulking surgery (PDS) or interval debulking surgery (IDS) remains unclear. Therefore, we aimed to examine TLS in tumor tissues collected during PDS and IDS for patients with EOC to evaluate its prognostic significance.

Patients and Methods: We examined TLS in EOC tumor tissues obtained during PDS or IDS from patients treated between 2017 and 2020 at the National Cancer Center Hospital East, Kashiwa, Japan. The association of tumor-infiltrating lymphocyte frequency, TLS presence, and programmed death-ligand 1 (PD-L1) expression with progression-free (PFS) and overall (OS) survival, and the association between TLS and PD-L1 expression were analyzed.

Results: Overall, 25 specimens (15 from PDS and 10 from IDS) were analyzed. The presence of TLS was associated with a significantly longer OS (median: 32.3 vs. 21.3 months, p=0.0455) in patients who underwent PDS but not in patients who underwent IDS (median: could not be calculated, p=0.9678). No association was identified between TLS and PFS in patients with PDS or with IDS (median: 31.1 vs. 17.3 months, p=0.3970; median: 28.7 vs. 16.3 months for median without TLS, p=0.1653). However, TLS was positively correlated with PD-L1 positivity (p=0.0094).

Conclusion: The prognostic impact of TLS, specifically in pre-chemotherapy specimens, and a positive association between TLS and PD-L1 indicate the potential of TLS as a meaningful biomarker for understanding antitumor immunity and developing immunotherapy for EOC.