Potential predictors of chemotherapy response in ovarian cancer--how do we define chemosensitivity?

The aim of this study was to assess whether microvessel density (measured by CD31), vascular endothelial growth factor (VEGF) or multidrug resistance (MDR1) could determine the response to chemotherapy or act as prognostic factors in ovarian cancer.

Seventy-nine ovarian specimens were immunostained. Pearson correlation, 1-way ANOVA and chi-square were used for univariate analysis. Kaplan Meier survival curves were used, log-rank was used for univariate analysis and a Cox proportional hazards regression model was used for multivariate evaluation. Response to chemotherapy was assessed after 6 months and again after 1 year.

Quantifying VEGF proved to be a valuable independent prognostic indicator in progression-free survival (PFS) (p<0.05) and overall survival (OS) (p<0.0001). VEGF correlated with response to chemotherapy at the 6-month interval (r=0.446, p<0.001) but failed to correlate at the 1-year interval. Increased staining with CD31 was associated with decreased PFS (p<0.01) and OS (p<0.01) in univariate but not multivariate analysis. MDR1 failed to act as a prognostic marker or as a predictor of response to chemotherapy.

VEGF correlates with response to chemotherapy at the 6-month but not the 12-month interval. What should our criteria be for determining sensitivity to chemotherapy? CD31, VEGF and MDR1 do play a role in some ovarian malignancies but other factors are likely to be involved and perhaps molecular profiling will determine which factors will be important for determining the response to chemotherapy.