Novel predictive models of early death less than one year in patients with metastatic RCC treated with first-line tyrosine kinase inhibitors.

Abstract

552 Background: Although the IMDC model can provide useful information on overall survival outcomes in patients with metastatic renal cell carcinoma (mRCC), this model maybe invaluable in patients who experience early death less than one year after initial systemic therapy. Here, we aimed to develop a new prognostic model which can predict early death in patients with mRCC receiving first line tyrosine kinase inhibitors (TKI). Methods: We retrospectively evaluated a total of 498 patients treated with first line line TKI among 537 patients with mRCC at our institution. The primary endpoint was the rate of early death within 1 year after first line TKI administration. We selected statistically significant factors predicting early death by performing multiple logistic regression. Modified IMDC model 1 based on existing IMDC model and model 2 composed of new variables were generated. The prediction accuracy was evaluated by calculating the concordance index (C-index). Area under curve (AUC) and net reclassification index (NRI) using ROC curve analysis were used to compare the predictive power between the models. Results: Overall mortality was 59.0% (n = 294) in 498 patients, and early mortality was 19.7% (n = 98) within 1 year after first line TKI administration. The C-index of the IMDC model for early death was 0.655. Five variables were selected: previous nephrectomy, BMI, multiple metastases, previous metastasectomy and serum albumin level. The C-index of the model 1, which includes five new variables plus variables in the IDMC model, is 0.823, showing a significant improvement over the IDMC model. In model 2, hemoglobin and neutrophil levels were added in new five variables, and the C-index was 0.822. For the IMDC model, there was a significant NRI difference in both models 1 and 2, but no significant difference in NRI between models 1 and 2. (-0.0368 [95% CI = -0.1416 - 0.0681]; p = 0.491). Conclusions: In this study, we suggest modified IMDC models for predicting ‘early death less than one year in patients with mRCC treated with first line TKI. These novel models can provide better treatment strategies and counseling in patients with mRCC who were treated by first line TKI.