Recurrent epithelial ovarian cancer: validation and improvement of an established prognostic index

To validate and improve an established prognostic index in patients with recurrent ovarian cancer.

A Canadian three-covariate prognostic index (tumour grade at diagnosis, initial performance status, and time to relapse/primary progression (TRP)) was validated in a well-defined cohort of comparable Danish patients. Potential parameters to be included in an improved prognostic index were revealed by univariate and multivariate analyses in the Danish validation group.

The Canadian index validated in the Danish patient population (n=189) found a statistical significant difference in survival between the prognostic groups good and intermediate (P<0.0001), whereas there was no significant difference in survival between the prognostic groups intermediate and poor (P=0.51). In order to improve the accuracy of the index, the candidate parameters, treatment free interval (TFI), CA125 level and performance status, at time of relapse/primary progression, were added, whereas the parameters, tumour grade, and initial performance status, from the Canadian index were excluded. As the correlation coefficient between TRP and TFI was very high (r=0.91), TRP was substituted with TFI in the improved prognostic model. The final model was: 0.8 (performance status)+0.33 log (CA125)-1.31 log (TFI). The improved model was a good predictor of one-year survival (AUC 0.85; logistic regression; P<0.0001). The median survival (with 95% CI) of the four prognostic groups (A-D) was 50.6 (34.0-not available), 25.0 (22.1-33.6), 11.3 (8.5-12.9), and 5.2 (3.5-6.3) months, respectively.

A novel prognostic model (the Copenhagen index) for patients with recurrent ovarian cancer is presented.