Peer-review started: August 30, 2014
First decision: September 28, 2014
Revised: October 10, 2014
Accepted: November 17, 2014
Article in press: November 19, 2014
Published online: January 27, 2015
Sorafenib is an effective anti-angiogenic treatment for hepatocellular carcinoma (HCC). The assessment of tumor progression in patients treated with sorafenib is crucial to help identify potentially-resistant patients, avoiding unnecessary toxicities. Traditional methods to assess tumor progression are based on variations in tumor size and provide unreliable results in patients treated with sorafenib. New methods to assess tumor progression such as the modified Response Evaluation Criteria in Solid Tumors or European Association for the Study of Liver criteria are based on imaging to measure the vascularization and tumor volume (viable or necrotic). These however fail especially when the tumor response results in irregular development of necrotic tissue. Newer assessment techniques focus on the evaluation of tumor volume, density or perfusion. Perfusion computed tomography and Dynamic Contrast-Enhanced-UltraSound can measure the vascularization of HCC lesions and help predict tumor response to anti-angiogenic therapies. Mean Transit Time is a possible predictive biomarker to measure tumor response. Volumetric techniques are reliable, reproducible and time-efficient and can help measure minimal changes in viable tumor or necrotic tissue, allowing the prompt identification of non-responders. Volume ratio may be a reproducible biomarker for tumor response. Larger trials are needed to confirm the use of these techniques in the prediction of response to sorafenib.
Core tip: The development of new treatment options for hepatocellular carcinoma has changed not only the way in which cancer is treated, but also how it is diagnosed and especially the assessment of tumor response. The traditional radiologic methods, which are mainly based on the evaluation of variations in tumor size, are considered insufficiently sensitive and unreliable in determining tumor progression when targeted therapies like sorafenib are involved. New assessment tools trying to combine morphological and vascular functional data to obtain an accurate measurement of tumor characteristics such as volume, density or vascularization, showed positive results in assessing patient’s response to therapy.