DETECTION AND SIGNIFICANCE OF OCCULT METASTASES IN NODE-NEGATIVE BREAST-CANCER

The clinical value of lymph node immunohistochemistry was assessed in 343 consecutive patients with apparently node-negative breast cancer u sing antimucin monoclonal antibodies BC2, BC3 and 3E1.2. Occult metast ases were detected in 41 patients (12 per cent). Although most of thes e were micrometastatic (< 2 mm in diameter), larger or diffuse deposit s were found in ten patients. Blind assessment of repeat haematoxylin and eosin stained sections detected metastases in ten of the 41 patien ts with occult metastases. After a median follow-up of 79 months, pati ents with occult metastases had a shorter time to disease recurrence ( P < 0.05) but not to death. After adjustment for other prognostic fact ors, the presence of occult metastases in two or more nodes was the mo st significant predictor of both disease recurrence (P < 0.01) and dea th (P < 0.01). When the ten patients with positive haematoxylin and eo sin sections were excluded from the analysis, the presence of occult m etastases in two or more nodes was still associated with a reduced dis ease-free interval (P < 0.05) and survival (P < 0.05). Lymph node immu nohistochemistry is a simple technique affording more accurate definit ion of nodal involvement than conventional methods.