Clinical evaluation of vascular normalization induced by recombinant human endostatin in nasopharyngeal carcinoma via dynamic contrast-enhanced ultrasonography

BACKGROUND: The present study confirmed the presence and exact range of “vascular normalization window” induced by recombinant human endostatin (RHES) in patients with nasopharyngeal carcinoma (NPC) by analyzing the variation of dynamic contrast-enhanced ultrasonography (DCE-US) quantitative parameters. Also, the clinical application of DCE-US in the evaluation of vascular normalization was assessed. MATERIALS AND METHODS: A total of 30 previously untreated patients with stage III–IVA NPC were enrolled in the present study and were randomly but equally divided into RHES (endostar [ES]) and normal saline (NS) groups. The patients in the ES group were administered RHES intravenously, while the patients in the NS group were administered normal saline daily for 5 days prior to intensity modulated radiotherapy coupled with concurrent chemotherapy. All patients underwent DCE-US on the day before the administration and on days 3 and 5 subsequently. The Audio Video Interleave of each DCE-US examination was analyzed quantitatively using the CHI-Q software. Several parameters were investigated, such as peak intensity (PI), time to peak (TTP), and mean transit time (MTT). RESULTS: The PI, TTP, and MTT differed significantly at the three time points in the ES group (all P<0.001) but not in the NS group (all P>0.05). In the ES group, PI increased and subsequently decreased, whereas TTP, as well as MTT, lessened initially and then increased within the 5 days after administration of RHES. The maximum value of PI and the minimum value of TTP, as well as MTT, occurred on day 3 (all P<0.05). Furthermore, the values of PI, TTP, and MTT were similar prior to the administration of RHES in both groups (all P>0.05). However, the PI of the ES group was significantly higher (P<0.05), whereas the TTP and the MTT were significantly lower following administration of RHES (all P<0.05) compared with the corresponding parameters of the NS group. CONCLUSION: DCE-US is a suitable method for the clinical evaluation of vascular normalization induced by antiangiogenic agents. The “vascular normalization window” induced by RHES occurs in patients with NPC, and the exact range is within about 5 days post-administration, which contributes towards optimizing the modality of RHES combined with radiotherapy and chemotherapy for NPC patients.