IMAGING OF ESTROGEN-RECEPTORS IN PRIMARY AND METASTATIC BREAST-CANCERPATIENTS WITH IODINE-123-LABELED Z-MIVE

Purpose: To evaluate the feasibility of noninvasive imaging estrogen r eceptors (ERs) in primary and metastatic breast cancer with the iodine -123-labeled ER-specific ligand cis-11 beta-methoxy-17 alpha-iodovinyl estradiol-17 beta (Z-[I-123]MIVE) using conventional nuclear medicine techniques. Patients and Methods: Z-[I-123]MIVE planar scintigraphy an d single-photon emission computed tomography (SPECT) were performed in 12 patients with proven primary breast cancer and 13 patients with pr oven or from other imaging modalities evident bone, liver, lung, pleur a and/or lymph node metastases. The results were compared with those o f ER immunohistochemistry (IHC), Blocking studies with the antiestroge n tamoxifen were performed to test whether Z-[I-123]MIVE tumor uptake was ER-mediated, Results: planar imaging showed uptake in 11 of 12 pri mary carcinomas. ER IHC performed for nine of these was positive, For the planar scintigraphy-negative patient, SPECT was faintly positive, but ER IHC negative (agreement, 90%), In nine of 13 metastatic patient s, planar scintigraphy was positive, The agreement between the results of ER IHC on the original primary tumor and of Z-[I-123]MIVE scintigr aphy was 82%, Specificity of tumor Z-[I-123]MIVE uptake was establishe d by complete blockade of uptake by tamoxifen, except in two patients who showed progressive disease, Z-[I-123]MIVE scintigraphy also enable d discriminating metastases from confounding nonmalignant abnormalitie s of the bone scan,Conclusion: Z-[I-123]MIVE scintigraphy shows high s ensitivity and specificity for the detection of ER-positive breast can cer, This may have impact on diagnostic possibilities and therapeutic management, Since ER imaging shows the functional status, addressing k nown intratumoral and intertumoral ER heterogeneity, it may improve th e characterization of disease and the selection of patients who may be nefit from hormonal therapy. (C) 1997 by American Society of Clinical Oncology.