title: Lymph node identification following neoadjuvant therapy in rectal cancer: A stage-stratified analysis using the surveillance, epidemiology, and end results (SEER)-medicare database.
abstract: OBJECTIVE
  Neoadjuvant chemoradiation (nCRT) for rectal adenocarcinoma reduces lymph node (LN) identification following surgical resection. We sought to evaluate the relationship between LN identification following nCRT and disease-specific survival (DSS), stratified by pathologic stage.
  
  
  METHODS
  The SEER-Medicare database (2000-2009) was queried for 1,216 pathologic stage I-III rectal cancer patients who underwent nCRT followed by curative-intent resection. Cox regressions evaluated the association between pathologic stage and DSS for LN cut-points from ≥2 up to ≥12 LNs.
  
  
  RESULTS
  Extent of LN identification did not influence DSS in ypStage I or ypStage III disease; in particular, the 12 LN cut-point was not associated with DSS for ypStage I (HR 1.29, P = 0.51) or ypStage III (HR 1.08, P = 0.42) patients. In ypStage II patients, actuarial survival improved continually with increasing lymph node identification up to ≥12 LNs. The 5 LN cut-point was associated with the greatest reduction of risk of cancer death (HR 0.56, P = 0.006), with decreasing magnitudes of survival benefit associated with nodal counts beyond 5 LN. The 12 LN cut-point was not associated with DSS in ypStage II patients (HR 0.67, P = 0.07).
  
  
  CONCLUSIONS
  The association between DSS and LN identification is a dynamic outcome that varies by pathologic stage, with unique prognostic significance for ypStage II patients.
authors.affiliation: Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Brett L
authors.initials: BL
authors.lastname: Ecker
authors.affiliation: Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania.|Department of Surgery, Philadelphia Veterans Affairs Medical Center, Philadelphia, Pennsylvania.
authors.forename: Emily C
authors.initials: EC
authors.lastname: Paulson
authors.affiliation: Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Jashodeep
authors.initials: J
authors.lastname: Datta
authors.affiliation: Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Arjun N
authors.initials: AN
authors.lastname: Jeganathan
authors.affiliation: Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Cary
authors.initials: C
authors.lastname: Aarons
authors.affiliation: Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Rachel R
authors.initials: RR
authors.lastname: Kelz
authors.affiliation: Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Najjia N
authors.initials: NN
authors.lastname: Mahmoud
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality* / Q000473:pathology* / Q000628:therapy; D000368:Aged; D000369:Aged, 80 and over; D059248:Chemoradiotherapy / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008297:Male; D006278:Medicare; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000009:adverse effects*; D009367:Neoplasm Staging; D011379:Prognosis; D012004:Rectal Neoplasms / Q000401:mortality* / Q000473:pathology* / Q000628:therapy; D018426:SEER Program; D015996:Survival Rate; D014481:United States
keywords: SEER; lymph node staging; neoadjuvant therapy; rectal cancer; survival