Baseline blood volume identified by dynamic contrast-enhanced computed tomography as a new independent prognostic factor in metastatic renal cell carcinoma

BackgroundPreliminary data showed prognostic impact of contrast-enhanced computed tomography (DCE-CT) identified Blood Volume (BV) in patients with metastatic renal cell carcinoma (mRCC). BV as an independent prognostic factor remains to be assessed.Materials and MethodsDCE-CT identified BV was prospectively quantified in patients with mRCC receiving first line therapies, adjusted for International mRCC Database Consortium (IMDC) individual features and treatments, and associated with overall survival (OS), progression-free survival (PFS) and objective response (ORR), using Cox and logistic regression, respectively.Results105 patients with mRCC were included. Median baseline BV was 32.87 mL × 100 g⁻¹ (range 9.52 to 92.87 mL × 100 g⁻¹). BV above median was associated with IMDC favorable risk category (P = 0.004), metastasis free interval ≥ 1 year (P = 0.007), male gender (P = 0.032), normal hemoglobin (P = 0.040) and normal neutrophils (P = 0.007), whereas low BV was associated with poor risk IMDC features (P < 0.05). Patients with high vs. low baseline BV had longer PFS (12.5 vs. 5.6 months, P = 0.015) and longer OS (42.2 vs. 22.4 months, P = 0.001), respectively. In multivariate analysis high baseline BV remained independent favorable for OS (HR 0.49, 95% CI 0.30–0.78, P = 0.003) and PFS (HR 0.64; 95% CI 0.42–0.97, P = 0.036). BV as a continuous variable was also associated with OS in the multivariate analysis (HR 0.98, 95% CI 0.96–1.00, P = 0.017). The estimated concordance index (c-index) was 0.688 using IMDC score and 0.701 when BV was added.ConclusionsDCE-CT identified Blood Volume is a new, independent prognostic factor in mRCC, which may improve the prognostic accuracy of IMDC.