BACKGROUND. Since anti-angiogenic treatment may induce necrosis with no change in tumor volume, new imaging methods are particularly suitable for the assessment of the response, for which the
RECIST size criteria appear inappropriate. Perfusion Computed Tomography (CTp) scan has recently been proposed for evaluating therapeutic response, demonstrating changes in tumor parenchymal
perfusion and emergence of necrosis even with no change in tumor volume. The aim of the study was to use the quantitative functional information and high spatial resolution of CTp to study
neovascolarization of hepatic metastases.
PATIENTS AND METHODS. CTp was used to prospectively evaluate 48 hepatic lesions in 15 patients (male 10, female 5; age range 44-78 years, mean 58.2 years) with metastatic colorectal adenocarcinoma
receiving bevacizumab since January 2008. CTp scan was performed the day before (day -1) starting antiangiogenic therapy and at days 90 and 180. The tumor perfusion parameters evaluated were blood
flow (BF), blood volume (BV) and capillary permeability surface area (PS).
RESULTS. Tumor blood flow at baseline was inversely associated with patient progression-free survival. Compared with baseline, bevacizumab induced a significant decrease in the estimated parameters
BF, BV and PS on days 90 and 180. Mean change in BF was 54%, in BV 35% and PS 59%. Patients with progressive disease had a lower percent decrease in all parameters than those with stable disease or
CONCLUSION. CTp allow evaluation of tumour angiogenesis in vivo. Patients with highly vascularized liver metastases as shown by high baseline tumor BF appear to have a worse prognosis than those
who do not. Baseline and percent change in BF, BV and PS by CTp scan following bevacizumab administration correlated with clinical outcome.