title: How Often Is Treatment Effect Identified in Axillary Nodes with a Pathologic Complete Response After Neoadjuvant Chemotherapy?
abstract: False-negative rates (FNR) of sentinel node biopsy (SNB) after neoadjuvant chemotherapy (NAC) in node-positive (N+) breast cancer patients are <10 % when ≥3 negative SNs are obtained. Marking positive nodes has been suggested to reduce FNR. Identification of treatment effect in the nodes post-NAC is an alternative to decrease FNR. We evaluated the frequency of treatment effect in N+ patients after a pathologic complete response (pCR) with NAC.
  
  
  
  Biopsy-proven N+ patients receiving NAC were identified. Patients with nodal pCR after axillary lymph node dissection (ALND) or SNB with dual mapping and ≥3 SNs removed were evaluated for treatment effect; ALND and SNB patients were compared.
  
  
  
  From January 2009 to December 2015, 528 N+ patients received NAC. Of these, 204 had a nodal pCR, 135 had an ALND, and 69 had SNB. Median age was 49 years, 15 % were hormone receptor positive (HR+)/HER2-, 27 % triple negative, and 58 % HER2+. The median number of nodes removed in ALND patients was 17 versus 4 in SNB patients. Treatment effect in nodes was identified in 192 patients (94 %) and was more common in ALND versus SNB patients (97 vs 88 %; p = .02). HR+ patients and patients without a breast pCR were less likely to have treatment effect in the nodes (p = .05). Other characteristics did not differ.
  
  
  
  Following NAC, SNs with treatment effect were retrieved in 88 % of patients without marking nodes, suggesting that nodal clipping may not be necessary to achieve an acceptable FNR. Longer follow-up is needed to determine regional recurrence rates in the SN-only cohort.
authors.affiliation: Breast Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA. barrioa@mskcc.org.
authors.forename: Andrea V
authors.initials: AV
authors.lastname: Barrio
authors.affiliation: Breast Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Anita
authors.initials: A
authors.lastname: Mamtani
authors.affiliation: Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Marcia
authors.initials: M
authors.lastname: Edelweiss
authors.affiliation: Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Anne
authors.initials: A
authors.lastname: Eaton
authors.affiliation: Breast Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Michelle
authors.initials: M
authors.lastname: Stempel
authors.affiliation: Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Melissa P
authors.initials: MP
authors.lastname: Murray
authors.affiliation: Breast Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Monica
authors.initials: M
authors.lastname: Morrow
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001365:Axilla; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology / Q000601:surgery*; D017024:Chemotherapy, Adjuvant; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D008197:Lymph Node Excision; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D000071036:Sentinel Lymph Node / Q000473:pathology* / Q000601:surgery; D021701:Sentinel Lymph Node Biopsy; D016896:Treatment Outcome; D064726:Triple Negative Breast Neoplasms / Q000473:pathology / Q000601:surgery
chemical_list: D000970:Antineoplastic Agents; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human