Effect of Occult Metastases on Survival in Node-Negative Breast Cancer

TLDR: Occult metastases were an independent prognostic variable in patients with sentinel nodes that were negative on initial examination; however, the magnitude of the difference in outcome at 5 years was small, and these data do not indicate a clinical benefit of additional evaluation, including immunohistochemical analysis, of initially negative sentinel node in Patients with breast cancer.

Abstract: BackgroundRetrospective and observational analyses suggest that occult lymph-node metastases are an important prognostic factor for disease recurrence or survival among patients with breast cancer. Prospective data on clinical outcomes from randomized trials according to sentinel-node involvement have been lacking. MethodsWe randomly assigned women with breast cancer to sentinel-lymph-node biopsy plus axillary dissection or sentinel-lymph-node biopsy alone. Paraffin-embedded tissue blocks of sentinel lymph nodes obtained from patients with pathologically negative sentinel lymph nodes were centrally evaluated for occult metastases deeper in the blocks. Both routine staining and immunohistochemical staining for cytokeratin were used at two widely spaced additional tissue levels. Treating physicians were unaware of the findings, which were not used for clinical treatment decisions. The initial evaluation at participating sites was designed to detect all macrometastases larger than 2 mm in the greatest dimens...