A meta-analysis of prognostic factors in advanced ovarian cancer with median survival and overall survival (measured with the log (relative risk)) as main objectives

Abstract

We performed a meta-analysis of 38 articles containing 66 treatment groups and 3443 patients in order to evaluate prognostic factors in advanced epithelial ovarian cancer. To evaluate overall survival we designed a method to summarize the overall survival curve into one single figure: the log (relative risk) (LRR). This is the first meta-analysis using overall survival (measured with the LRR) as an objective. We found that the main prognostic factors predicting an improved survival (measured with the LRR) are: chemotherapy including cisplatin as initial treatment, a residual tumour mass of less than 2 cm prior to therapy, FIGO stage II/III and a good performance status. In a multivariate model, the use of cisplatin and the residual tumour were found to be the only factors of prognostic relevance. No relation between median survival and the overall clinical response rate of all patients entered in the denominator, could be demonstrated. Undifferentiated tumours and patients treated with cisplatin regimens had higher response rates to treatment but younger patients and those with endometrioid histology were less likely to respond. A surgical complete remission was encountered more frequently among studies that included a high number of patients with small tumour masses prior to treatment. Trials using cisplatin included more patients with small tumour nodules in their patient material compared to studies not using this drug. The data illustrate the danger of comparing studies with each other. In the trials with a high percentage of patients with small tumour residuals in the study population more toxic deaths were seen. This probably reflects the fact that they had received more intensive treatment. The LRR correlated strongly with the median survival, response and the percentage of surgical complete remissions. We concluded that the introduction of the LRR can be a meaningful addition to the evaluation of the influence of prognostic factors on overall survival.