Value of Contrast-Enhanced Ultrasound Quantification Criteria for Identifying Patients not Responding to Bevacizumab-Based Therapy for Colorectal Liver Metastases

PURPOSE: To evaluate changes in tumor vascularization parameters based on contrast-enhanced ultrasound (CEUS) quantification criteria of at least one visible liver metastasis as an early predictor of non-response to chemotherapy, including bevacizumab for colorectal cancer (CRC) liver metastases. MATERIALS AND METHODS: This multicenter prospective study included patients who received first-line bevacizumab-based chemotherapy. Tumor enhancement measured using CEUS within one liver metastasis and in relation to the surrounding healthy liver was quantified within 8 days before the first infusion of bevacizumab (E0), 24 hours after the end of the first infusion of bevacizumab (E1), in the 24 hours before the 2nd and 3 rd infusion of bevacizumab on day 15 (E2) and day 30 (E3), respectively, and after 2 months of treatment (E4). Endpoints were tumor response using RECIST criteria at 2 months, progression-free survival (PFS) and overall survival (OS). RESULTS: Among the 137 patients included in this study, 109 were analyzed. Only CEUS parameters calculated in relation to healthy liver were significant. High wash-in and wash-out rates at baseline were significantly associated with a better tumor response. Increases over time E2-E0 and E3-E0 for peak enhancement were significantly associated with shorter progression-free survival. Increases over time E2-E0 and E3-E0 for peak enhancement and wash-in area under the curve were significantly associated with a shorter overall survival. CONCLUSION: This large study demonstrated that early dynamic changes in the vascularity of liver metastases evaluated by quantified CEUS are associated with outcome in patients receiving first-line bevacizumab-based treatment for metastatic CRC