title: Local recurrence after surgery for non-small cell lung cancer: a recursive partitioning analysis of multi-institutional data.
abstract: OBJECTIVE
  To define subgroups at high risk of local recurrence (LR) after surgery for non-small cell lung cancer using a recursive partitioning analysis (RPA).
  
  
  METHODS
  This Institutional Review Board-approved study included patients who underwent upfront surgery for I-IIIA non-small cell lung cancer at Duke Cancer Institute (primary set) or at other participating institutions (validation set). The 2 data sets were analyzed separately and identically. Disease recurrence at the surgical margin, ipsilateral hilum, and/or mediastinum was considered an LR. Recursive partitioning was used to build regression trees for the prediction of local recurrence-free survival (LRFS) from standard clinical and pathological factors. LRFS distributions were estimated with the Kaplan-Meier method.
  
  
  RESULTS
  The 1411 patients in the primary set had a 5-year LRFS rate of 77% (95% confidence interval [CI], 0.74-0.81), and the 889 patients in the validation set had a 5-year LRFS rate of 76% (95% CI, 0.72-0.80). The RPA of the primary data set identified 3 terminal nodes based on stage and histology. These nodes and their 5-year LRFS rates were as follows: (1) stage I/adenocarcinoma, 87% (95% CI, 0.83-0.90); (2) stage I/squamous or large cell, 72% (95% CI, 0.65-0.79); and (3) stage II-IIIA, 62% (95% CI, 0.55-0.69). The validation RPA identified 3 terminal nodes based on lymphovascular invasion (LVI) and stage: (1) no LVI/stage IA, 82% (95% CI, 0.76-0.88); (2) no LVI/stage IB-IIIA, 73% (95% CI, 0.69-0.80); and (3) LVI, 58% (95% CI, 0.47-0.69).
  
  
  CONCLUSIONS
  The risk of LR was similar in the primary and validation patient data sets. There was discordance between the 2 data sets regarding the clinical factors that best segregate patients into risk groups.
authors.affiliation: Department of Radiation Oncology, Duke Cancer Institute, Durham, NC. Electronic address: kelse003@mc.duke.edu.
authors.forename: Chris R
authors.initials: CR
authors.lastname: Kelsey
authors.forename: Kristin A
authors.initials: KA
authors.lastname: Higgins
authors.forename: Bercedis L
authors.initials: BL
authors.lastname: Peterson
authors.forename: Junzo P
authors.initials: JP
authors.lastname: Chino
authors.forename: Lawrence B
authors.initials: LB
authors.lastname: Marks
authors.forename: Thomas A
authors.initials: TA
authors.lastname: D'Amico
authors.forename: John M
authors.initials: JM
authors.lastname: Varlotto
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D008207:Lymphatic Metastasis; D008297:Male; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D018365:Neoplasm, Residual; D011013:Pneumonectomy / Q000009:adverse effects / Q000401:mortality; D012044:Regression Analysis; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States
keywords: 10.2; 10.4; CI; HR; LR; LRFS; LVI; NSCLC; RPA; confidence interval; hazard ratio; local recurrence; local recurrence-free survival; lymphovascular invasion; non–small cell lung cancer; recursive partitioning analysis