title: Comparative analysis of various prognostic nodal factors, adjuvant chemotherapy and survival among stage III colon cancer patients over 65 years: an analysis using surveillance, epidemiology and end results (SEER)-Medicare data.
abstract: OBJECTIVE
  The prognostic effects of chemotherapy and various lymph node measures [positive nodes, total node count and the positive lymph node ratio (PLNR)] have been established. It is unknown whether the cancer-specific survival benefit of chemotherapy differs across these nodal prognostic categories.
  
  
  METHODS
  This retrospective analysis of linked Surveillance, Epidemiology and End Results (SEER) data and Medicare data (SEER-Medicare)included patients ≥ 65 years of age with a diagnosis of stage III colon cancer between 1997 and 2002. We grouped patients according to the number of positive nodes (N1 and N2), total node count (≥ 12 and < 12 total nodes) and PLNR (below the 75th percentile and at least at the 75th percentile of the PLNR). The end point was colon cancer-specific mortality.
  
  
  RESULTS
  Fifty-one per cent (3701) of the 7263 patients received adjuvant therapy during the time period 1997-2002. The mean (standard deviation) number of total nodes examined was 13 (9) and the number of positive nodes identified was 3 (3). Patients with N2 disease, < 12 total nodes examined and a high PLNR had a worse survival at 2, 3 and 5 years following colectomy. Utilization of chemotherapy demonstrated a colon cancer-specific survival benefit (hazard ratio at median follow up = 0.7; P < 0.001) that was consistent and statistically significant across the three nodal prognostic categories examined.
  
  
  CONCLUSIONS
  The benefit of chemotherapy did not vary based on N stage, total node count or PLNR. The results favour a broad-based approach towards increasing the chemotherapy treatment rates in stage III patients of ≥ 65 years of age, rather than an approach that targets clinical subgroups.
authors.affiliation: Department of Surgery, University of Maryland, Baltimore, Maryland 21201, USA. nhanna@smail.umaryland.edu
authors.forename: N N
authors.initials: NN
authors.lastname: Hanna
authors.forename: E
authors.initials: E
authors.lastname: Onukwugha
authors.forename: M A
authors.initials: MA
authors.lastname: Choti
authors.forename: A J
authors.initials: AJ
authors.lastname: Davidoff
authors.forename: I H
authors.initials: IH
authors.lastname: Zuckerman
authors.forename: V D
authors.initials: VD
authors.lastname: Hsu
authors.forename: C D
authors.initials: CD
authors.lastname: Mullins
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017024:Chemotherapy, Adjuvant; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000401:mortality* / Q000473:pathology; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D006278:Medicare; D009367:Neoplasm Staging; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018426:SEER Program; D016019:Survival Analysis; D014481:United States / Q000453:epidemiology