title: GTV differentially impacts locoregional control of non-small cell lung cancer (NSCLC) after different fractionation schedules: subgroup analysis of the prospective randomized CHARTWEL trial.
abstract: OBJECTIVE
  To evaluate the impact of fractionation schedule on the size of the gross tumour volume (GTV) effect on tumour control after radiotherapy of NSCLC.
  
  
  METHODS
  A subgroup analysis on 163 patients treated in a randomized phase III trial of CHARTWEL (continuous hyperfractionated accelerated radiotherapy-weekend less) vs conventional radiotherapy was performed. The influence of GTV and other baseline factors on local failure (LF), disease-free survival (DFS), distant metastases (DM), and overall survival (OS) was estimated using the Cox Proportional Hazards model.
  
  
  RESULTS
  Superior local control was achieved by CHARTWEL compared to conventional radiotherapy (HR 0.54, p=0.015). The hazard of LF increased with increasing GTV for both conventional fractionation and CHARTWEL, however the increase for the latter was less pronounced and not significant.
  
  
  CONCLUSIONS
  Highly accelerated CHARTWEL treatment was significantly more effective than conventional radiotherapy for locoregional control of NSCLC. GTV had a significant effect on locoregional control after conventional fractionation, an effect that was not significant with CHARTWEL. This is the first study to demonstrate that the magnitude of the time factor of fractionated radiotherapy increases with tumour volume.
authors: Department of Radiation Oncology and OncoRay - Center for Radiation Research in Oncology, Technische Universität Dresden, Germany; Department of Oncology, Alexandria University, Egypt.
authors: Maher
authors: M
authors: Soliman
authors: Ala
authors: A
authors: Yaromina
authors: Steffen
authors: S
authors: Appold
authors: Daniel
authors: D
authors: Zips
authors: Carsten
authors: C
authors: Reiffenstuhl
authors: Andreas
authors: A
authors: Schreiber
authors: Howard D
authors: HD
authors: Thames
authors: Mechthild
authors: M
authors: Krause
authors: Michael
authors: M
authors: Baumann
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D047368:Tumor Burden