title: Residual mesorectal lymph node involvement following neoadjuvant combined-modality therapy: rationale for radical resection?
abstract: BACKGROUND
  In order to evaluate the impact of preoperative radiation and chemotherapy (combined modality therapy, or CMT) on primary rectal cancer and mesorectal lymph nodes (MLNs), middle and lower third rectal cancers were resected with total mesorectal excision (TME) and assessed for frequency of MLN retrieval and residual MLN involvement.
  
  
  METHODS
  Between 1990 and 2001, 187 consecutive patients underwent abdominoperineal resection (APR) or low anterior resection (LAR) for locally advanced (endorectal ultrasound [ERUS] stage, T3-4) mid and distal rectal cancer following preoperative CMT. Sphincter preservation was possible in 150 patients (80%). The mean number of retrieved MLNs was 10.6. Pre-CMT ERUS stage was compared with final pathologic stage.
  
  
  RESULTS
  Comparison of pre-CMT ERUS stage with pathologic stage revealed a decrease in T stage in 93 patients (49%), as well as a decrease in the percentage of individuals with positive MLNs, from 54% to 27% (P <.0001). The overall incidence of positive MLN involvement was 27%, and incidence paralleled pathologic T stage (pT): pT0 = 7%, pT1 = 8%, pT2 = 22%, pT3 = 37%, and pT4 = 67%.
  
  
  CONCLUSIONS
  Following preoperative CMT, the incidence of residual MLN involvement remains significant and parallels increasing pT stage. Therefore, the standard of care for locally advanced distal rectal cancer should continue to include formal rectal resection (TME).
authors.affiliation: Colorectal Service, Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York, USA.
authors.forename: Francesco
authors.initials: F
authors.lastname: Stipa
authors.forename: Alma
authors.initials: A
authors.lastname: Zernecke
authors.forename: Harvey G
authors.initials: HG
authors.lastname: Moore
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Minsky
authors.forename: W Douglas
authors.initials: WD
authors.lastname: Wong
authors.forename: Martin
authors.initials: M
authors.lastname: Weiser
authors.forename: Philip B
authors.initials: PB
authors.lastname: Paty
authors.forename: Jinru
authors.initials: J
authors.lastname: Shia
authors.forename: Jose G
authors.initials: JG
authors.lastname: Guillem
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D015994:Incidence; D008207:Lymphatic Metastasis / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D018365:Neoplasm, Residual / Q000453:epidemiology; D009519:New York City / Q000453:epidemiology; D012004:Rectal Neoplasms / Q000473:pathology* / Q000601:surgery / Q000628:therapy*; D012189:Retrospective Studies