PREOPERATIVE ASSESSMENT OF AXILLARY LYMPH-NODE STATUS IN PATIENTS WITH BREAST ADENOCARCINOMA USING INTRAVENOUS (99M)TECHNETIUM MAB-170H.82 (TRUSCINT(R)AD(TM))

Immunoscintigraphy of the axilla has potential utility for the diagnos tic and prognostic assessment of patients with breast adenocarcinoma. mAb-170H.82 is a murine monoclonal antibody (mAb) derived against synt hetic Thomsen-Friedenreich (TF) antigen. Tru-Scint(R)AD(TM), a Tc-99m- mAb-170H.82 immunoconjugate, has previously been shown to localize in various human adenocarcinomas. The purpose of this study was to evalua te the accuracy of this immunoconjugate in the pre-operative assessmen t of axillary lymph nodes in patients with known breast adenocarcinoma . Sixteen patients with documented primary breast cancer were injected intravenously with 1 mg of immunoconjugate (radioactivity 1.8 GBq) an d imaged 22-24 hrs post-injection. Both planar and single photon emiss ion computed tomographic (SPECT) images were obtained and reviewed in a blinded fashion. Imaging results were compared with surgical and pat hological findings. Seven of 16 patients were found to have histologic ally positive axillary nodes: 5 of these sites were detected by immuno scintigraphy (sensitivity = 71%). Nine patients had pathologically dis ease-free axillary nodes: only 1 of these was misidentified as positiv e by immunoscintigraphy (specificity = 89%). These results suggest tha t immunoscintigraphy with Tc-99m-mAb-170H.82 has promise in the detect ion of axillary lymph node involvement in patients with breast cancer. Further studies are warranted to define the role of immunoscintigraph y in axillary staging.