Detection of "occult" lymph node metastasis in breast cancer: should pathologists go the extra mile?

Approximately 25% of patients with stage I (node negative) breast cancer relapse at a rate similar to those with stage II disease. Inadvertent pathologic "understaging" of lymph node status is one plausible explanation for this phenomenon. While many studies have shown that additional sectioning +/- immunohistochemical staining for epithelial markers increases the rate of detection of small deposits of metastatic carcinoma, few have had sufficient statistical power to examine the impact of "occult" metastasis on clinical outcome. This provocative update by the International Ludwig Breast Cancer Study Group provides support for considering going "the extra mile" to detect lymph node metastasis in postmenopausal patients and those with the lobular subtype of invasive breast cancer.