89Zr- Bevacizumab PET Imaging in Primary Breast Cancer

Vascular endothelial growth factor (VEGF)-A is overexpressed in most malignant and premalignant breast lesions. VEGF-A can be visualized noninvasively with PET imaging and using the tracer Zr-89-labeled bevacizumab. In this clinical feasibility study, we assessed whether VEGF-A in primary breast cancer can be visualized by Zr-89-bevacizumab PET. Methods: Before surgery, breast cancer patients underwent a PET/CT scan of the breasts and axillary regions 4 d after intravenous administration of 37 MBq of Zr-89-bevacizumab per 5 mg. PET images were compared with standard imaging modalities. Zr-89-bevacizumab uptake was quantified as the maximum standardized uptake value (SUVmax). VEGF-A levels in tumor and normal breast tissues were assessed with enzyme-linked immunosorbent assay. Data are presented as mean +/- SD. Results: Twenty-five of 26 breast tumors (mean size +/- SD, 25.1 +/- 19.8 mm; range, 4-80 mm) in 23 patients were visualized. SUVmax was higher in tumors (1.85 +/- 1.22; range, 0.52-5.64) than in normal breasts (0.59 6 0.37; range, 0.27-1.69; P<0.001). The only tumor not detected on PET was 10 mm in diameter. Lymph node metastases were present in 10 axillary regions; 4 could be detected with PET (SUVmax, 2.66 +/- 2.03; range, 1.32-5.68). VEGF-A levels in the 17 assessable tumors were higher than in normal breast tissue in all cases (VEGF-A/mg protein, 184 +/- 169 pg vs. 10 +/- 21 pg; P = 0.001), whereas Zr-89-bevacizumab tumor uptake correlated with VEGF-A tumor levels (r = 0.49). Conclusion: VEGF-A in primary breast cancer can be visualized by means of Zr-89-bevacizumab PET.