title: Breast cancer metastasis burden in sentinel nodes analysed using one-step nucleic acid amplification predicts axillary nodal status.
abstract: BACKGROUND
  In breast cancer patients undergoing sentinel lymph node biopsy (SLNB) analysis using one-step nucleic acid amplification (OSNA), clarity is required as to the risk factors for non-sentinel lymph node (NSLN) involvement upon axillary lymph node dissection (ALND). This study aims to identify these factors, including categorising by extent of sentinel node positivity: solitary positive node (solitary), multiple nodes with some positive (multiple incomplete positive), or multiple nodes all of which are positive (multiple all positive).
  
  
  METHODS
  We conducted a cohort study using prospectively collected data on 856 SLNBs analysed using OSNA, from patients with cT1-3 clinically node-negative invasive breast cancer. ALND was performed for 289 positive SLNBs.
  
  
  RESULTS
  NSLN metastases were identified in 73 (25.3%) ALNDs. Significant factors for NSLN involvement on multivariate analysis were: SLNB macrometastases (cytokeratin-19 mRNA count >5000 copies/μl) (adj.OR = 3.01; 95% CI, 1.61-5.66; p = 0.0006), multiple all positive vs. multiple incomplete positive SLNB (adj.OR = 2.92; 95% CI, 1.38-6.19; p = 0.0050), and undergoing mastectomy (adj.OR = 1.89; 95% CI, 1.00-3.55; p = 0.0486). Amongst multiple incomplete positive SLNBs, an 8.8% NSLN risk was identified when only micrometastases were present.
  
  
  CONCLUSIONS
  Extent of sentinel lymph node positivity measured using OSNA predicts NSLN metastasis risk, aiding decisions surrounding axillary treatment.
authors.affiliation: The Royal Surrey County Hospital NHS Foundation Trust, Egerton Road, Guildford, Surrey GU2 7XX, United Kingdom; University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom. Electronic address: tommilner1@doctors.org.uk.
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Milner
authors.affiliation: University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom.
authors.forename: Simon
authors.initials: S
authors.lastname: de Lusignan
authors.affiliation: University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom.
authors.forename: Simon
authors.initials: S
authors.lastname: Jones
authors.affiliation: The Royal Surrey County Hospital NHS Foundation Trust, Egerton Road, Guildford, Surrey GU2 7XX, United Kingdom.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Jackson
authors.affiliation: The Royal Surrey County Hospital NHS Foundation Trust, Egerton Road, Guildford, Surrey GU2 7XX, United Kingdom; University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom.
authors.forename: Graham T
authors.initials: GT
authors.lastname: Layer
authors.affiliation: The Royal Surrey County Hospital NHS Foundation Trust, Egerton Road, Guildford, Surrey GU2 7XX, United Kingdom.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Kissin
authors.affiliation: The Royal Surrey County Hospital NHS Foundation Trust, Egerton Road, Guildford, Surrey GU2 7XX, United Kingdom.
authors.forename: Tracey E
authors.initials: TE
authors.lastname: Irvine
mesh_terms: D000328:Adult; D000368:Aged; D001365:Axilla; D001943:Breast Neoplasms / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D053539:Keratin-19 / Q000235:genetics; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis; D008408:Mastectomy; D008875:Middle Aged; D061206:Neoplasm Micrometastasis; D021141:Nucleic Acid Amplification Techniques; D011237:Predictive Value of Tests; D012333:RNA, Messenger / Q000032:analysis*; D021701:Sentinel Lymph Node Biopsy; D047368:Tumor Burden
chemical_list: D053539:Keratin-19; D012333:RNA, Messenger
keywords: Breast cancer; One-step nucleic acid amplification (OSNA); Sentinel lymph node