Assessment of the tumor microenvironment in cervix cancer using dynamic contrast enhanced CT, interstitial fluid pressure and oxygen measurements

Purpose: Interstitial fluid pressure (IFP) and oxygen (pO 2) measurements are prognostic factors in cervical cancer. The purpose of this study was to determine the relationship between IFP and oxygenation and parameters derived from dynamic contrast-enhanced computed tomography (DCE-CT). Methods and Materials: Dynamic contrast-enhanced computed tomography was performed in 32 patients with cervical cancer before radiation therapy. Images were acquired during intravenous contrast injection at 1 per s for 120 s and 1 per 15 s for 60 s. DCE-CT was analyzed using CT Perfusion 3 software (GE Medical Systems) to derive tumor blood flow (BF), permeability surface area product, blood volume, and mean transit time. Further analysis was performed to obtain relative peak enhancement, residual enhancement at 3 min after contrast injection (RE), time to peak and initial slope. Nodal status and tumor size were assessed with MRI. From in vivo IFP ( n = 31) and pO 2 ( n = 31) tumor measurements median pO 2 (mO 2), percentage measurements less than 5 mm Hg (HP5) and mean IFP values were calculated. Results: There was a positive correlation between BF and mO 2 ( r = 0.47, p = 0.007) and between RE and HP5 ( r = 0.39, p = 0.03). There was no correlation between IFP and DCE-CT parameters. Conclusion: There is a moderately positive, correlation between tumor oxygenation and BF as well as RE and HP5. Further study is required to determine if DCE-CT parameters are useful predictors of tumor behavior in cervical cancer.