OCCULT AXILLARY NODE METASTASES IN BREAST-CANCER - THEIR DETECTION AND PROGNOSTIC-SIGNIFICANCE

Although the presence of axillary node metastases in breast cancer is a key prognostic indicator and may influence treatment decisions, a si gnificant proportion of patients diagnosed as axillary node negative ( ANN) using standard histopathological techniques may have occult nodal metastases (OMs). A combination of limited step-sectioning (4 x 100 m u m intervals) and immunohistochemical staining (with cytokeratin (MNF .116) and MUCl (BC2) antibodies) was used to detect OM in a retrospect ive series of 208 ANN patients. OMs were found in 53 patients (25%), a nd both step-sectioning and immunohistochemical detection significantl y improved detection (P<0.05). Detection using BC2 (25%) was superior to MNF.116 (8%) and haematoxylin and eosin (H&E) (8%). OMs were found in 51 patients using only the first and deepest sectioning levels and BC2 staining. OMs were more frequently found in lobular (38%) than duc tal carcinoma (25%), and more frequently in women less than 50 years ( 41%) than in older women (19%). Univariate overall and disease-free su rvival analyses showed that the presence, size and number of OM had pr ognostic significance as did tumour size (disease-free only) and histo logical and nuclear grade (P>0.05). Cox multivariate proportional haza rd regression analyses showed that the presence and increasing size of OMs were significantly associated with poorer disease-free survival. independently of other prognostic factors (P> 0.05). However there was not a significant independent association of the presence of occult m etastases with overall survival (P=0.11). These findings have importan t implications with regard to selection of ANN patients for adjuvant t herapy.