Tumor Size and Overall Survival in Patients With Platinum-Resistant Ovarian Cancer Treated With Chemotherapy and Bevacizumab

INTRODUCTION: Ovarian cancer is now recognized as a constellation of distinct subtypes of neoplasia involving the ovary and related structures. As a consequence of this heterogeneity, the analysis of covariates influencing the overall survival is crucial in this disease segment. In this work, an overall survival model incorporating tumor kinetics metrics in patients with platinum-resistant ovarian cancer was developed from the randomized, open label, phase 3 AURELIA trial. METHODS: Tumor size data from 361 patients randomly allocated to the bevacizumab + chemotherapy or chemotherapy study arm were collected at baseline and every 8 to 9 weeks until disease progression. Patients continued to be followed for survival after treatment discontinuation. A landmarked Cox proportional hazard survival model was developed to characterize the overall survival distribution. RESULTS: Two sets of factors were found to be influential on survival time: those describing the type and severity of disease (Eastern Cooperative Oncology Group [ECOG], Féderation Internationale de Gynécologie et d’Obstétrique [FIGO] stages, presence of ascites) and those summarizing the key features of the tumor kinetic model (tumor shrinkage at week 8 and tumor size at treatment onset). The treatment group was not required in the final model as the drug effect was accounted for in the tumor kinetics model. CONCLUSIONS: This work has identified both ascites and tumor kinetics metrics as being the 2 most influential factors to explain variability in overall survival in patients with platinum-resistant ovarian cancer.