Clinical relevance of contrast-enhanced ultrasound in monitoring anti-angiogenic therapy of cancer: Current status and perspectives

Angiogenesis regulation is one of the newest fronts in the fight against cancer. Anti-angiogenic therapy is based on inhibiting factors required to solicit vessel formation thus cutting-off the tumor's supply of nutriments and oxygen. Initial vascular response is followed by formation of necrosis. Volumetric regression occurs more tardively. Effective monitoring of this new therapeutic approach thus requires imaging techniques that can detect early microvascular changes. A number of clinical studies provide evidence that contrast-enhanced ultrasound (CEUS) can provide early indication of tumor response to anti-angiogenic therapy. More sophisticated imaging and analysis techniques for CEUS and contrast agents targeted for adhesion to anti-angiogenic markers have also demonstrated promise in animal model studies. This review underlines the relevance of CEUS for anti-angiogenic therapy monitoring by summarizing the current clinical results, emerging CEUS techniques and preclinical data.