title: Adaptive/nonadaptive proton radiation planning and outcomes in a phase II trial for locally advanced non-small cell lung cancer.
abstract: OBJECTIVE
  To analyze dosimetric variables and outcomes after adaptive replanning of radiation therapy during concurrent high-dose protons and chemotherapy for locally advanced non-small cell lung cancer (NSCLC).
  
  
  METHODS
  Nine of 44 patients with stage III NSCLC in a prospective phase II trial of concurrent paclitaxel/carboplatin with proton radiation [74 Gy(RBE) in 37 fractions] had modifications to their original treatment plans after re-evaluation revealed changes that would compromise coverage of the target volume or violate dose constraints; plans for the other 35 patients were not changed. We compared patients with adaptive plans with those with nonadaptive plans in terms of dosimetry and outcomes.
  
  
  RESULTS
  At a median follow-up of 21.2 months (median overall survival, 29.6 months), no differences were found in local, regional, or distant failure or overall survival between groups. Adaptive planning was used more often for large tumors that shrank to a greater extent (median, 107.1 cm(3) adaptive and 86.4 cm(3) nonadaptive; median changes in volume, 25.3% adaptive and 1.2% nonadaptive; P<.01). The median number of fractions delivered using adaptive planning was 13 (range, 4-22). Adaptive planning generally improved sparing of the esophagus (median absolute decrease in V(70), 1.8%; range, 0%-22.9%) and spinal cord (median absolute change in maximum dose, 3.7 Gy; range, 0-13.8 Gy). Without adaptive replanning, target coverage would have been compromised in 2 cases (57% and 82% coverage without adaptation vs 100% for both with adaptation); neither patient experienced local failure. Radiation-related grade 3 toxicity rates were similar between groups.
  
  
  CONCLUSIONS
  Adaptive planning can reduce normal tissue doses and prevent target misses, particularly for patients with large tumors that shrink substantially during therapy. Adaptive plans seem to have acceptable toxicity and achieve similar local, regional, and distant control and overall survival, even in patients with larger tumors, vs nonadaptive plans.
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Eugene J
authors.initials: EJ
authors.lastname: Koay
authors.forename: David
authors.initials: D
authors.lastname: Lege
authors.forename: Radhe
authors.initials: R
authors.lastname: Mohan
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Komaki
authors.forename: James D
authors.initials: JD
authors.lastname: Cox
authors.forename: Joe Y
authors.initials: JY
authors.lastname: Chang
mesh_terms: D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use; D016190:Carboplatin / Q000627:therapeutic use; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D003131:Combined Modality Therapy / Q000379:methods; D004947:Esophagus / Q000000981:diagnostic imaging / Q000528:radiation effects; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D058958:Organs at Risk / Q000000981:diagnostic imaging / Q000528:radiation effects; D017239:Paclitaxel / Q000627:therapeutic use; D011446:Prospective Studies; D061766:Proton Therapy; D011522:Protons / Q000009:adverse effects; D011832:Radiation Injuries / Q000517:prevention & control*; D011859:Radiography; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D013116:Spinal Cord / Q000000981:diagnostic imaging / Q000528:radiation effects; D016896:Treatment Outcome; D047368:Tumor Burden
chemical_list: D000970:Antineoplastic Agents; D011522:Protons; D016190:Carboplatin; D017239:Paclitaxel