The preoperative detection of axillary lymph node metastases in breast cancer by isotope imaging

Abstract

Abstract Axillary lymphoscintigraphy using 99Tcm-labelled liposomes was carried out in 40 patients with breast cancer as a part of pretreatment staging in an attempt to improve the accuracy of axillary evaluation. Patients were injected interstitially in the periareolar region of each breast with 250–300 μCi of 99Tcm-labelled liposomes. Subsequently the patients were imaged with a gamma-camera using computerized data processing. Interpretation of images was based on prior experimental data; a diminished uptake of isotope by the primary regional lymph node (PRLN) and the group of axillary regional lymph nodes (RLN) draining the tumour, when compared to the control side, was considered to be abnormal and to suggest node metastases. An equal or enhanced uptake by the PRLN or RLN draining the tumour, when compared to the control side, was considered normal, indicating an absence of lymph node metastases. Eighteen patients (45 per cent) had abnormal scans and 14 patients (35 per cent) had normal scans. Eight patients (20 per cent) had technically unsatisfactory images where axillary nodes could not be identified. Twenty-two patients of the 32 with evaluable scans had correlation of preoperative images with postsurgical axillary lymph node histopathology. One patient out of 12 with an abnormal scan had normal lymph nodes on serial sectioning, and 2 patients out of 10 with normal scans had lymph node metastases. Eight of the 32 patients (25 per cent) with evaluable images had enhanced uptake of isotope by the PRLN and RLN draining the tumour. In 3 of these cases a marked reactive hyperplasia only was shown on histopathological examination, in 2 cases the reactive hyperplasia was associated with lymph node metastases, accounting for the 2 false negative interpretations. This preliminary study suggests that axillary lymphoscintigraphy may be of value in preoperative staging in breast cancer. Long term studies are needed to evaluate the prognostic potential of such a test as a measure of macrophage function. Further studies, by blind replication, are required to evaluate the accuracy of axillary lymph node imaging.