Association between baseline and changes in hemoglobin levels and treatment response and prognosis in metastatic renal cell carcinoma: A Mexican retrospective study.

518 Background: Clinical markers of response and outcome in metastatic renal cell carcinoma (mRCC) are lacking. Low hemoglobin (Hb) is associated with poor outcomes in the IMDC risk score. Hb levels also appear to be associated with mRCC response to VEGFI monotherapy, although this relationship is nuclear. This study evaluates the role of Hb increases as a predictive biomarker of clinical response and outcomes. Methods: Patients with advanced RCC treated with VEGF receptor tyrosine kinase inhibitors (TKIs) as a first-line therapy were identified. Hemoglobin levels were retrieved at baseline and then at monthly intervals for 6 months. Absolute and percentage increases over baseline were evaluated as predictors of objective response rate, progression free survival. Patients were categorized as responders (CR+PR) or nonresponders (SD+PD) using cross-sectional imaging at week 12. The Kaplan-Meier method was used to estimate PFS for patients who had an increase vs. decrease from baseline Hb, and the log-rank test used to assess survival differences between the groups. The Cox proportional hazards model was used for univariate and multivariate regression analysis to determine the significance of individual variables on PFS. Results: Among the 47 eligible patients, elevations in hemoglobin were observed in 64%. The median age at start of treatment was 59 years. Changes in hemoglobin at time of response were associated with objective response rate. Landmark analysis at 1 month showed that increases in hemoglobin were associated with longer PFS (mPFS 15 vs. 50 months; P = .004) Responders had a significantly higher Hb level than nonresponders at 1rs month P= 0.004. An increase in Hb was a significant independent predictor of progression-free survival (HR 0.47, P= .039). Conclusions: In this retrospective clinical study, we demonstrate that Hb levels are a valuable clinical marker of outcomes in patients receiving first-line therapy for mRCC in our population. These findings are readily applicable to routine clinical practice and may help clinicians deliver more personalized care.