title: Predictors of lymph node count in colorectal cancer resections: data from US nationwide prospective cohort studies.
abstract: OBJECTIVE
  To identify factors that influence the total and negative lymph node counts in colorectal cancer resection specimens independent of pathologists and surgeons.
  
  
  METHODS
  We used multivariate negative binomial regression. Covariates included age, sex, body mass index, family history of colorectal carcinoma, year of diagnosis, hospital setting, tumor location, resected colorectal length (specimen length), tumor size, circumferential growth, TNM stage, lymphocytic reactions and other pathological features, and tumor molecular features (microsatellite instability, CpG island methylator phenotype, long interspersed nucleotide element 1 [LINE-1] methylation, and BRAF, KRAS, and PIK3CA mutations).
  
  
  METHODS
  Two US nationwide prospective cohort studies.
  
  
  METHODS
  Patients with rectal and colon cancer (N=918).
  
  
  METHODS
  The negative and total node counts (continuous).
  
  
  RESULTS
  Specimen length, tumor size, ascending colon location, T3N0M0 stage, and year of diagnosis were positively associated with the negative node count (all P.002). Mutation of KRAS might also be positively associated with the negative node count (P=.03; borderline significance considering multiple hypothesis testing). Among node-negative (stages I and II) cases, specimen length, tumor size, and ascending colon location remained significantly associated with the node count (all P.002), and PIK3CA and KRAS mutations might also be positively associated (P=.03 and P=.049, respectively, with borderline significance).
  
  
  CONCLUSIONS
  This molecular pathological epidemiology study shows that specimen length, tumor size, tumor location, TNM stage, and year of diagnosis are operator-independent predictors of the lymph node count. These crucial variables should be examined in any future evaluation of the adequacy of lymph node harvest and nodal staging when devising individualized treatment plans for patients with colorectal cancer.
authors.affiliation: Department of Medical Oncology, Dana-Farber Cancer Institute and Havard Medical School, Boston, MA 02215, USA.
authors.forename: Teppei
authors.initials: T
authors.lastname: Morikawa
authors.forename: Noriko
authors.initials: N
authors.lastname: Tanaka
authors.forename: Aya
authors.initials: A
authors.lastname: Kuchiba
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Nosho
authors.forename: Mai
authors.initials: M
authors.lastname: Yamauchi
authors.forename: Jason L
authors.initials: JL
authors.lastname: Hornick
authors.forename: Richard S
authors.initials: RS
authors.lastname: Swanson
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Chan
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Meyerhardt
authors.forename: Curtis
authors.initials: C
authors.lastname: Huttenhower
authors.forename: Deborah
authors.initials: D
authors.lastname: Schrag
authors.forename: Charles S
authors.initials: CS
authors.lastname: Fuchs
authors.forename: Shuji
authors.initials: S
authors.lastname: Ogino
mesh_terms: D000368:Aged; D003110:Colonic Neoplasms / Q000235:genetics / Q000473:pathology* / Q000601:surgery; D019175:DNA Methylation / Q000235:genetics; D004273:DNA, Neoplasm / Q000235:genetics; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D015999:Multivariate Analysis; D009154:Mutation; D009367:Neoplasm Staging; D011518:Proto-Oncogene Proteins / Q000235:genetics; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras); D012004:Rectal Neoplasms / Q000235:genetics / Q000473:pathology* / Q000601:surgery; D012044:Regression Analysis; D014481:United States; D018631:ras Proteins / Q000235:genetics
chemical_list: D004273:DNA, Neoplasm; C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins