title: IMRT and 3D conformal radiotherapy with or without elective nodal irradiation in locally advanced NSCLC: A direct comparison of PET-based treatment planning.
abstract: OBJECTIVE
  The potential of intensity-modulated radiation therapy (IMRT) as opposed to three-dimensional conformal radiotherapy (3D-CRT) is analyzed for two different concepts of fluorodeoxyglucose positron emission tomography (FDG PET)-based target volume delineation in locally advanced non-small cell lung cancer (LA-NSCLC): involved-field radiotherapy (IF-RT) vs. elective nodal irradiation (ENI).
  
  
  METHODS
  Treatment planning was performed for 41 patients with LA-NSCLC, using four different planning approaches (3D-CRT-IF, 3D-CRT-ENI, IMRT-IF, IMRT-ENI). ENI included a boost irradiation after 50 Gy. For each plan, maximum dose escalation was calculated based on prespecified normal tissue constraints. The maximum prescription dose (PD), tumor control probability (TCP), conformal indices (CI), and normal tissue complication probabilities (NTCP) were analyzed.
  
  
  RESULTS
  IMRT resulted in statistically significant higher prescription doses for both target volume concepts as compared with 3D-CRT (ENI: 68.4 vs. 60.9 Gy, p < 0.001; IF: 74.3 vs. 70.1 Gy, p < 0.03). With IMRT-IF, a PD of at least 66 Gy was achieved for 95 % of all plans. For IF as compared with ENI, there was a considerable theoretical increase in TCP (IMRT: 27.3 vs. 17.7 %, p < 0.00001; 3D-CRT: 20.2 vs. 9.9 %, p < 0.00001). The esophageal NTCP showed a particularly good sparing with IMRT vs. 3D-CRT (ENI: 12.3 vs. 30.9 % p < 0.0001; IF: 15.9 vs. 24.1 %; p < 0.001).
  
  
  CONCLUSIONS
  The IMRT technique and IF target volume delineation allow a significant dose escalation and an increase in TCP. IMRT results in an improved sparing of OARs as compared with 3D-CRT at equivalent dose levels.
authors.affiliation: Department of Radiotherapy and Radiation Oncology, Saarland University Medical School, 66421, Homburg/Saar, Germany. jochen.fleckenstein@uks.eu.
authors.forename: Jochen
authors.initials: J
authors.lastname: Fleckenstein
authors.affiliation: Department of Radiotherapy and Radiation Oncology, Saarland University Medical School, 66421, Homburg/Saar, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Kremp
authors.affiliation: Department of Radiotherapy and Radiation Oncology, Saarland University Medical School, 66421, Homburg/Saar, Germany.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Kremp
authors.affiliation: Department of Radiotherapy and Radiation Oncology, Saarland University Medical School, 66421, Homburg/Saar, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Palm
authors.affiliation: Department of Radiotherapy and Radiation Oncology, Saarland University Medical School, 66421, Homburg/Saar, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Rübe
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology / Q000532:radiotherapy*; D019788:Fluorodeoxyglucose F18; D021621:Imaging, Three-Dimensional; D008175:Lung Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D015182:Lymphatic Irradiation / Q000379:methods*; D064847:Multimodal Imaging / Q000379:methods*; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography / Q000379:methods*; D011446:Prospective Studies; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: Conformal radiotherapy; Intensity-modulated radiation therapy; Non-small cell lung carcinoma; Organs at risk; Positron emission tomography