The aim of this study was to investigate the potential of a new iodobenzamide, N-[2-(1'-piperidinyl)ethyl]-3-(123)I-iodo-4-methoxybenzamide (P-(123)I-MBA), to visualize primary breast tumor in humans in vivo. Tumor accumulation of benzamides is based on a preferential binding to sigma receptors that are overexpressed on breast cancer cells.
Methods: P-(123)I-MBA (148-185 MBq) was administered to 12 patients with a mammographically suspicious breast mass. Two hours after administration, whole-body and spot images of the healthy and the diseased breast were obtained.
Results: A focal increased tracer accumulation was observed in 8 of 10 patients with histologically confirmed breast cancer (mean tumor-to-background ratio, 2.04). No uptake was seen in a case of lymphatic adenitis.
Conclusion: This preliminary patient study shows that P-(123)I-MBA accumulates in most breast tumors in vivo. Future work should focus on the relationship between P-(123)I-MBA uptake and the proliferative activity of cells to anticipate use of this technique as a tool to noninvasively assess the degree of tumor proliferation.