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

Abstract

Background Preliminary 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 Methods DCE-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. Results 105 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. Conclusions DCE-CT identified Blood Volume is a new, independent prognostic factor in mRCC, which may improve the prognostic accuracy of IMDC.

Prognostic value of DCE-CT-derived blood volume and flow compared to core biopsy microvessel density in patients with metastatic renal cell carcinoma

“…To control for imbalances in established prognostic factors, we compared baseline patient characteristics in the present cohort ( n = 25) with the previously published cohort ( n = 105) [ 15 ]. We found no difference in IMDC risk groups ( p = 0.188), sex ( p = 0.893), treatment ( p = 0.122), age ( p = 0.371), synchronous versus .…”

“…We have previously established that the DCE-CT parameter BV was an independent prognostic factor that added to the prognostic accuracy of IMDC [ 15 – 18 ]. Analogous to our previous findings, we were able to identify the same positive association between overall survival and baseline BV deconv , BV Patlak , or BF deconv in only 25 patients in the present study.…”

“…The clinical results from DaRenCa-1 [ 8 ], the prognostic impact on survival outcome of baseline DCE-CT identified BV [ 15 ], and the association between DCE-CT parameters and early treatment response [ 16 – 18 ] in this patient group have previously been published.…”

“…The median follow-up time in alive patients was assessed using the reverse Kaplan-Meier survival method. The association between baseline clinical factors in this present study ( n = 25) was compared to baseline clinical factors in the previously published study ( n = 105) [ 15 ] using χ 2 or Fischer exact test, when applicable.…”

“…This enables an assessment of vascular support over the scanned tissue by performing a calculation of functional perfusion parameters such as blood flow (BF) and blood volume (BV), parameters which are closely correlated with angiogenesis [ 12 – 14 ]. In patients with mRCC, high baseline BV has been associated with favourable baseline clinical factors, while low BV has been associated with unfavourable baseline clinical factors, and high baseline BV has been demonstrated as an independent favorable prognostic factor for survival outcome [ 15 ]. Furthermore, a decline in DCE-CT-identified parameters BV or BF during early treatment has shown correlation to favourable survival outcomes [ 16 – 18 ].…”