Dose-response relationship in cisplatin-treated breast cancer xenografts monitored with dynamic contrast-enhanced ultrasound

BACKGROUND: Exactly assessing tumor response to different dose of chemotherapy would help to tailor therapy for individual patients. This study was to determine the feasibility of dynamic contrast-enhanced ultrasound (CEUS) in the evaluation of tumor vascular response to different dose cisplatin. METHODS: MCF-7 breast cancer bearing mice were treated with different dose of cisplatin in group B (1 mg/kg) and group C (3 mg/kg). A control group A was given with saline. Sequential CEUS was performed on days 0, 3 and 7 of the treatment, in which time-signal intensity curves were obtained from the intratumoral and depth-matched liver parenchyma. Peak enhancement (PE), area under the curve of wash-in (WiAUC), wash-in rate (WiR) and wash-in perfusion index (WiPI) were calculated from perfusion time-intensity curves and normalized with respect to the adjacent liver parenchyma. Histopathological analysis was conducted to evaluate tumor cell density and microvascular density (MVD). RESULTS: Significant decreases in tumor normalized perfusion parameters were observed on day 3 in the high dose group and on day 7 in the low dose group. On day 7, nPE, nWiAUC, and nWiPI significantly decreased in group C and group B as compared with group A (P < 0.05), and further decreased in group C as compared with group B (P < 0.05). Significant decreases of tumor cell density and MVD were seen in treated group (group B and C) compared to control group (P < 0.05) and further decrease in group C compared to group B (P < 0.05). CONCLUSIONS: Dynamic CEUS for quantification of tumor perfusion could be used to evaluate tumor vascular response to different dose of chemotherapy.