title: Evolution of sentinel lymph node biopsy in breast cancer, in and out of vogue?
abstract: Sentinel lymph node biopsy (SLNB) was introduced 2 decades ago and thereafter validated for routine surgical management of breast cancer, including cases treated with neoadjuvant chemotherapy. As the number of lymph nodes for staging has decreased, pathologists have scrutinized SLN with a combination of standard hematoxylin and eosin, levels, immunohistochemistry (IHC), and molecular methods. An epidemic of small-volume metastases thereby arose, leading to modifications in the American Joint Committee on Cancer staging to accommodate findings such as isolated tumor cells (ITC) and micrometastases. With the goal of determining the significance of these findings, retrospective followed by prospective trials were performed, showing mixed results. The ACOSOG Z10 and NSABP B-32 trials both independently showed that ITC and micrometastases were not significant and thus discouraged the use of levels and IHC for detecting them. However, the Surveillance Epidemiology and End Results database showed that patients with micrometastases had an overall decreased survival. In addition, the MIRROR (Micrometastases and ITC: Relevant and Robust or Rubbish?) trial, showed that patients with ITC and micrometastases treated with adjuvant therapy had lower hazard ratios compared with untreated patients. Subsequently, the ACOSOG Z0011 trial randomized patients with up to 2 positive SLN to axillary lymph node dissection (ALND) or not, all treated with radiation and chemotherapy, showing no difference in survival or recurrence rates between the 2 groups and causing a shift from ALND. As the rate of ALND has declined, the necessity of performing levels, IHC, frozen section, and molecular studies on SLN needs to be revisited.
authors.affiliation: Department of Pathology, The Mount Sinai Medical Center, New York, NY.
authors.forename: Shabnam
authors.initials: S
authors.lastname: Jaffer
authors.forename: Ira J
authors.initials: IJ
authors.lastname: Bleiweiss
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D001943:Breast Neoplasms / Q000737:chemistry / Q000235:genetics / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D019317:Evidence-Based Medicine; D005260:Female; D005820:Genetic Testing / Q000639:trends; D049673:History, 20th Century; D049674:History, 21st Century; D006801:Humans; D007150:Immunohistochemistry / Q000639:trends; D008198:Lymph Nodes / Q000737:chemistry / Q000473:pathology*; D008207:Lymphatic Metastasis; D061206:Neoplasm Micrometastasis; D009367:Neoplasm Staging / Q000266:history / Q000639:trends*; D011237:Predictive Value of Tests; D016032:Randomized Controlled Trials as Topic; D021701:Sentinel Lymph Node Biopsy / Q000266:history / Q000639:trends*
chemical_list: D014408:Biomarkers, Tumor