PROGNOSTIC-SIGNIFICANCE OF OCCULT LYMPH-NODE METASTASES IN NODE-NEGATIVE BREAST-CANCER

Background: Lymph node status, established by a single hematoxylin and eosin (H&E) section from each node, remains an important prognostic i ndicator in patients with breast cancer, but used alone it is insuffic ient to identify patients who will develop metastatic disease. This st udy was conducted to assess the significance of detecting occult metas tases in 86 patients with breast cancer originally reported to be hist ologically node negative. None of the patients received adjuvant syste mic therapy. Methods: Five additional levels from formalin-fixed, para ffin-embedded nodes were examined at 150-mu m intervals with H&E stain ing and a cocktail of antikeratin antibodies (AE1/AE3) recognizing low molecular weight acidic keratins. Results: Nodes from 11 (12.8%) of 8 6 patients contained occult metastases. All metastases identified by c ytokeratin antibody were also detected in H&E-stained sections. With m edian followup of 80 months, distant metastases occurred in five of 11 occult node-positive patients (45%) and 13 of 75 patients whose nodes were negative on review (17%). Median time to recurrence was 89 month s for occult node-positive patients and not yet reached for node-negat ive patients (p = 0.048). The disease-specific 5-year survival rate wa s 90% for occult node-positive patients and 95% for node-negative pati ents. Conclusions: The presence of occult metastases shortened the dis ease-free interval and suggested that more diligent axillary staging w ould more accurately identify patients who would benefit from systemic adjuvant treatment.