Prognostic significance of Ki67 during neoadjuvant chemotherapy in primary unresectable ovarian cancer

Aim: The purpose of this study was to investigate whether the Ki67 values were associated with survival for predicting prognosis in patients with advanced ovarian cancer receiving neoadjuvant chemotherapy (NACT).

Methods: Among 17 patients treated with NACT, 13 patients were available for tissue samples from matched pre- and post-therapy tissues. Ki67 scores were transformed to a logarithmic scale for the statistical analyses. The optimal cutoff values of the log-phase Ki67 were assessed by receiver operating characteristic (ROC) analysis. Kaplan-Meier analysis, the log-rank test, and Cox regression analysis were carried out to analyze survival.

Results: The Ki67-decrease and post-NACT Ki67 were the independent factors associated with relapse-free survival (RFS) (p < 0.001 and p = 0.003). No association was observed on overall survival. The optimal cutoff values for the Ki67-decrease and the post-NACT Ki67 were 6.67% and 5.46 based on ROC where the area under ROC curves (AUC) were 1.00 (p < 0.001) with the 100% sensitivity and specificity. The median RFS was 537 days in patients showing Ki67-decrease >6.66% or post-NACT Ki67 level <5.46, while it was 224 days in those with Ki67 decrease ≤6.66% or post-NACT Ki67 level ≥5.46 (p = 0.001).

Conclusions: The Ki67-decrease and the lower post-NACT Ki67 are independent factors associated with favorable RFS, indicating that they could be precise biomarker candidates for prognosis in NACT-administered patients with advanced ovarian cancer.