⁸⁹Zr-Bevacizumab PET Imaging in Primary Breast Cancer

Abstract

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 ⁸⁹Zr-labeled bevacizumab. In this clinical feasibility study, we assessed whether VEGF-A in primary breast cancer can be visualized by ⁸⁹Zr-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 ⁸⁹Zr-bevacizumab per 5 mg. PET images were compared with standard imaging modalities. ⁸⁹Zr-bevacizumab uptake was quantified as the maximum standardized uptake value (SUV_max). 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. SUV_max was higher in tumors (1.85 ± 1.22; range, 0.52–5.64) than in normal breasts (0.59 ± 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 (SUV_max, 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 ⁸⁹Zr-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 ⁸⁹Zr-bevacizumab PET.