High density of CD66b in primary high-grade ovarian cancer independently predicts response to chemotherapy.

Purpose: 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.
Methods: 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.
Results: 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.
Conclusion: 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.