Intra-Tumoral Lymphocytic Infiltration Is Associated with Favorable Prognosis in Suboptimal Surgery in High-Grade Serous Ovarian Carcinoma

Background: Immunoreactive (IR) subtype is one of the subtypes of high-grade serous ovarian carcinoma (HGSOC) with intra-tumoral lymphocytic infiltration. A positive prognostic correlation between IR subtype and R0 + optimal surgery has been reported. This study investigates the prognostic significance of the tumor-infiltrating lymphocytes (TILs) in the suboptimal surgery group of HGSOCs. Methods: After reviewing 318 malignant ovarian tumors detected in our database between 2000 and 2017, 74 HGSOCs with supplemental p53 immunostaining were selected. Differences in progression-free survival (PFS) and overall survival (OS) between the 2 groups of the IR subtype and the other subtypes were investigated. Based on pathological findings, HGSOCs were divided into 2 groups: those with or without abundant TILs. Results: Abundant TILs were detected in 17 cases of HGSOC (22.9%). Clinicopathological characteristics including age, CA125, FIGO stage, and residual disease did not show significant differences between the 2 groups. Lymph node metastasis was more common in the IR subtype group (p=0.04). In the suboptimal surgery group, the 5-year PFS and OS (Kaplan-Meier estimates) in cases with (n=10) or without (n=21) abundant TILs were 10% and 0% (P=0.097) and 70% and 28.5% (P=0.012), respectively. The median time (range) to OS in cases with or without abundant TILs were 58 (34-81) months and 39 (22-55) months, respectively. Multivariate analysis in OS showed significant differences in TILs. Conclusions: Abundant intra-tumoral lymphocytic infiltration is an independent and favorable prognostic indicator for the suboptimal surgery group in HGSOCs, and is associated with treatment response via cancer immunity.