title: Is there a different dose-effect relation between the primary tumor and involved lymph nodes in locally advanced non-small-cell lung cancer? A hypothesis-generating study.
abstract: OBJECTIVE
  It is unknown whether the dose-response relation of the primary tumor in NSCLC is different from that of the involved lymph nodes (LN). As the recurrence rate is much lower in LN, we hypothesized that LN need a lower radiation dose.
  
  
  METHODS
  A retrospective analysis of prospective data was performed on patients with locally advanced NSCLC treated with (chemo)radiotherapy. The impact of EQD2,Tprescription dose on relapse was analyzed using Cox regression modeling correcting for baseline diameter.
  
  
  RESULTS
  From 2006 to 2010, 75 consecutive patients were included, resulting in 142 lymph nodes in the analysis. Any relapse (locoregional/distant) occurred in 58 patients (77%), while involved nodal relapse (INR) was observed in 13% of patients. No dose-response relationship was observed for INR (p = .22). Primary tumor progression was seen in 40% of patients together with a significant dose-response relationship (p = .033). Baseline nodal diameter was not associated with INR (p = .76), while primary tumor diameter was a highly significant predictor for relapse (p = .0031).
  
  
  CONCLUSIONS
  These results suggest that LN control may be achieved at lower radiation doses than needed for the primary tumor. Prospective dose de-escalation studies on LN are warranted to decrease the incidence of severe esophagitis without compromising local tumor control.
authors.affiliation: a Department of Radiation Oncology , University Hospitals Leuven , Leuven , Belgium.
authors.forename: Lisa
authors.initials: L
authors.lastname: Van den Bosch
authors.affiliation: b Experimental Radiation Oncology, Department of Oncology , KU Leuven , Leuven , Belgium.
authors.forename: Gilles
authors.initials: G
authors.lastname: Defraene
authors.affiliation: a Department of Radiation Oncology , University Hospitals Leuven , Leuven , Belgium.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Peeters
authors.affiliation: c Department of Respiratory Oncology , University Hospitals Leuven , Leuven , Belgium.
authors.forename: Christophe
authors.initials: C
authors.lastname: Dooms
authors.affiliation: d Department of Radiology , University Hospitals Leuven , Leuven , Belgium.
authors.forename: Walter
authors.initials: W
authors.lastname: De Wever
authors.affiliation: e Department of Nuclear Medicine , University Hospitals Leuven , Leuven , Belgium.
authors.forename: Christophe
authors.initials: C
authors.lastname: Deroose
authors.affiliation: a Department of Radiation Oncology , University Hospitals Leuven , Leuven , Belgium.|f Department of Radiation Oncology (Maastro Clinic) , GROW Research Institute, Maastricht University Medical Center , Maastricht , The Netherlands.
authors.forename: Dirk
authors.initials: D
authors.lastname: De Ruysscher
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology / Q000532:radiotherapy*; D059248:Chemoradiotherapy / Q000379:methods; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D008207:Lymphatic Metastasis / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000379:methods; D012189:Retrospective Studies