Tumor Shrinkage as a Prognostic Factor of Metastatic Renal Cell Carcinoma in the Era of Molecular Targeted Therapy

Abstract

We evaluated the impact of tumor shrinkage (TS) induced by molecular targeted therapy as the first-line systemic therapy on the survival of patients with metastatic renal cell carcinoma (mRCC). A total of 67 patients with mRCC who received first-line molecular targeted therapy were included in this study. Sixty patients were evaluable by response evaluation criteria in solid tumors. Patients underwent the first evaluation at 8-12 weeks after the start of the therapy. Twenty patients had TS ≧30%, 32 from 30% to -20%, and 8 ≦-20%. The median overall survival periods of patients who achieved TS ≧30%, from 30% to -20%, and ≦-20% at first evaluation were 41.0, 35.0, and 11.5 months, respectively. Univariate and multivariate analyses showed that TS of≧0%, in addition to negative C-reactive protein and the absence of bone metastasis were good predictors of overall survival. The patients who achieved 0% or more at the initial evaluation had longer survival than those who had no tumor reduction (40.0 months vs 12.0 months, p<0. 001). These findings suggest that early TS affects overall survival in real practice. We should consider alternative therapies for patients who have not achieved tumor reduction at the initial evaluation.