Background: Near-infrared diffuse optical imaging (DOSI) has been recently accepted as a method to assess tumor vascularity and oxygenation by measuring tissue hemoglobin (Hb) concentration. It is expected that DOSI could be used to monitor changes in vascularity after antiangiogenic therapy.
Methods: A patient with advanced breast cancer was treated with single-agent bevacizumab followed by addition of weekly paclitaxel to it. DOSI was performed in the tumor-bearing breast and contralateral normal breast at baseline, 3, 6, 12, 24 h, and then daily for 1 week. Images of a tumor-to-normal ratio of tHb (rtHb) were constructed for identifying a tumor lesion.
Results: Serial images of rtHb showed a tumor lesion which corresponded to a hot spot. The level of rtHb rapidly decreased within several hours after administration of single-agent bevacizumab and then persisted at low levels during treatment. From day 2, the value of rtHb gradually increased and peaked on day 5.
Conclusion: This trend may be explained considering sequential images of rtHb indicating the inhibition of angiogenesis due to antiangiogenic therapy. We conducted a clinical study using single-agent bevacizumab followed by neoadjuvant chemotherapy in primary breast cancer patients to understand vascular remodeling after antiangiogenic agent at very early time points using DOSI.