Influence of residual disease and extreme drug resistance assays on outcome in patients with epithelial ovarian cancer

Abstract

5504 Background: Extreme drug resistance (EDR) assays have been used as tools in identifying those agents that are least likely to be of clinical benefit in the treatment of epithelial ovarian cancer (EOC). We sought to examine the effect of obtaining EDR assays on the outcome of patients with EOC in the primary and recurrent setting. Methods: We conducted a retrospective review of demographic, pathologic, EDR assay and outcome data from 377 patients with EOC who had an assay sent at the time of their diagnosis or at recurrence. Univariate followed by multivariate analyses using Cox proportional hazards method were performed to identify and estimate the impact of independent prognostic factors on time to progression (TTP), overall survival (OS) and survival after recurrence (RS). Results: Increasing age was associated with a worse OS and RS (HR = 1.34; 95% CI, 1.14–1.58 and HR = 1.14; 95% CI, 1.00–1.31, for each decade increase in age respectively). Compared with patients with microscopic residual disease, patients who were left with 0.1 to 1.0 cm and >1.0 cm residual disease had an increased risk of recurrence (HR=1.94; 95% CI, 1.33 to 2.84 and HR=3.61; 95% CI; 2.07 to 6.39, respectively) and death (HR = 1.59; 95% CI, 1.03 to 2.45; and HR = 2.14; 95% CI, 1.09 to 4.20, respectively). For patients who recurred, those who did not undergo secondary cytoreductive surgery and patients who were left with >1.0 cm residual had an increased risk of death compared to patients with microscopic residual (HR = 2.13; 95% CI, 1.28 to 3.54; and HR = 2.84; 95% CI, 1.71 to 4.71, respectively). EDR assay results for single agents or combinations did not independently predict patient outcomes. Conclusions: The amount of residual disease continues to be an important prognostic factor, especially when all macroscopic disease is removed both in the primary and recurrent setting. Increasing age is also an independent predictor of OS and RS. EDR assay results do not independently predict or alter the outcomes of patients with EOC who are treated with the current standard of care including optimal cytoreductive surgery followed by platinum and taxane combination chemotherapy in either the primary or recurrent setting. No significant financial relationships to disclose.