More tumor‐affected lymph nodes because of the sentinel lymph node procedure but no stage migration, because the 2002 TNM classifies small tumor deposits as pathologic N0 breast cancer

Abstract

Introduction of the SN procedure has led to the detection of more tumor-affected lymph nodes because of the intensified workup of SNs by pathologists. However, stage migration did not occur when tumor deposits of <or=0.2 mm were categorized as lymph node-negative disease, according to the 2002 TNM classification.

Sentinel Lymph Node Biopsy and Isolated Tumor Cells in Invasive Lobular Versus Ductal Breast Cancer

“…Clinical Breast Cancer Month 2016 -3 which ITCs ( 0.2 mm) were categorized as lymph node-negative disease, actually prevented stage migration. 10 Thus, any further increase in the number of micrometastases detected because of the increasing number of SLN biopsies was counterbalanced by the introduction of pN0(iþ) as a separate category. The changed pN classification combined with the more appropriate use of the existing pN classifications largely explains the observed time trends, including the slightly lower number of macrometastases, the rapid increase in the number of micrometastases during the initial years of SLN introduction, and the increase in ITCs in more recent years.…”

“…9 Thus, no stage migration could be observed, because ITCs were considered to indicate node-negative disease. 10 Currently, with the SLN biopsy considered the standard of care for axillary staging in patients with clinically node-negative breast cancer has enabled the pathologist to perform a detailed examination of the SLN, including serial sectioning, hematoxylin and eosin (H&E) staining, and immunohistochemistry. 11 From pathologic studies of invasive lobular carcinoma (ILC), it is known that the nodal metastases of ILC can be difficult to detect on standard histologic sections using H&E, because they are composed of noncohesive cells of similar size to benign lymphocytes and histiocytes.…”