Ovarian carcinoma (OC) is the most lethal female genital cancer. After a primary curative surgical approach followed by chemotherapy, a fraction of the patients recur with chemoresistant disease. Data indicate a favorable therapeutic effect of tumor-infiltrating neutrophils (TIN) in OC. Our aim was to investigate the prognostic role of CD66b expression, corresponding to neutrophilic infiltration for recurrence-free survival (RFS) and overall survival (OS) in patients with OC.

A collective of 47 primary serous ovarian carcinoma and their matching recurrences were processed and stained with CD66b using immunohistochemistry. Tumors from patients with RFS of more than 6 months were defined as chemosensitive. Statistical analysis of CD66b expression was performed to assess the clinical endpoints.

High density of CD66b expressing neutrophils in primary carcinoma was associated with chemosensitivity (p = 0.014) and longer RFS (p = 0.001). Univariate analysis identified high density of CD66b expressing neutrophils as a predictor for favorable RFS (HR 0.41, 95% CI 0.22–0.76, p < 0.005). Residual disease > 2 cm (HR 3.67, 95% CI 1.62–8.31, p < 0.002) and higher number of chemotherapy cycles (HR 1.28, 95% CI 1.05–1.55, p < 0.013) were associated with worse RFS. Multivariate analysis showed that high density of CD66b expressing neutrophils (HR 0.22, 95% CI 0.10–0.48, p < 0.001) and residual disease > 2 cm (HR 3.69, 95% CI 1.43–9.53, p < 0.007) were independent predictors of RFS but had no impact on OS.

High CD66b neutrophil density in primary high-grade OC predicts good response to initial chemotherapy and longer recurrence-free survival independent of known risk factors.