Abstract
Background: The 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 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 two groups of the IR subtype and the other subtypes were investigated. Based on pathological findings, HGSOCs were divided into two 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 two 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.