title: Patterns of locoregional failure in stage III non-small cell lung cancer treated with definitive chemoradiation therapy.
abstract: OBJECTIVE
  Chemoradiation therapy (CRT) is the core treatment of locally advanced non-small cell lung cancer (LA-NSCLC), but potential toxicities limit radiation therapy dose. These toxicities, plus the advent of increasingly conformal radiation therapy, have prioritized target definition and the use of involved-field radiation therapy (IFRT). Published data largely focus on regional rather than local failure patterns. We report our pattern-of-failure experience treating patients with LA-NSCLC with definitive CRT, focusing on both local and regional recurrences with detailed dosimetric analyses of failure location.
  
  
  METHODS
  Patients treated between December 2004-2010 were included. Imaging scans from date of failure were fused with the RT-planning CT scan, and recurrent nodes were contoured to determine if the recurrence was in a previously irradiated region, defined as involved nodal recurrence (INR) versus elective nodal recurrence (ENR). Local failures were contoured and identified as in-field, marginal, or out-of-field based on dose received. Actuarial overall survival (OS) and progression-free survival (PFS) were calculated, and the cumulative incidences of local, regional, locoregional, and distant recurrence (CILR, CIRR, CILRR, CIDR) were determined with death as a competing risk.
  
  
  RESULTS
  One hundred five patients were included with a median survival of 21.8 months. The 3-year OS and PFS were 36% and 22%, respectively. The 3 year CILRR, CILR, CIRR, CIDR were 41%, 38%, 40%, and 58%, respectively. Thirty patients failed regionally, but only 7 patients developed an ENR with no concurrent local failure or INR, and only 1 of these patients did not develop distant metastases within 1 month of recurrence. A total of 21 patients (20%) developed an ENR with or without other areas of recurrence.
  
  
  CONCLUSIONS
  Elective regional recurrences rarely occurred as the sole site of failure, despite the use of IFRT. Moreover, the pattern of local failure was entirely in-field. These data strongly support field design focusing on gross nodal and primary disease.
authors.affiliation: Department of Radiation Oncology, Rush University Medical Center, Chicago, IIllinois. Electronic address: shalini_garg@rush.edu.
authors.forename: Shalini
authors.initials: S
authors.lastname: Garg
authors.affiliation: Department of Radiation Oncology, Rush University Medical Center, Chicago, IIllinois.
authors.forename: Benjamin T
authors.initials: BT
authors.lastname: Gielda
authors.affiliation: Department of Radiation Oncology, Rush University Medical Center, Chicago, IIllinois.
authors.forename: Krystyna
authors.initials: K
authors.lastname: Kiel
authors.affiliation: Department of Radiation Oncology, Rush University Medical Center, Chicago, IIllinois.
authors.forename: Julius V
authors.initials: JV
authors.lastname: Turian
authors.affiliation: Section of Medical Oncology, Rush University Medical Center, Chicago, Illinois.
authors.forename: Mary Jo
authors.initials: MJ
authors.lastname: Fidler
authors.affiliation: Section of Medical Oncology, Rush University Medical Center, Chicago, Illinois.
authors.forename: Marta
authors.initials: M
authors.lastname: Batus
authors.affiliation: Section of Medical Oncology, Rush University Medical Center, Chicago, Illinois.
authors.forename: Philip
authors.initials: P
authors.lastname: Bonomi
authors.affiliation: Department of Radiation Oncology, Rush University Medical Center, Chicago, IIllinois.
authors.forename: David J
authors.initials: DJ
authors.lastname: Sher
mesh_terms: D000230:Adenocarcinoma / Q000150:complications / Q000401:mortality / Q000473:pathology / Q000628:therapy; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D018287:Carcinoma, Large Cell / Q000150:complications / Q000401:mortality / Q000473:pathology / Q000628:therapy; D002289:Carcinoma, Non-Small-Cell Lung / Q000150:complications* / Q000401:mortality / Q000473:pathology / Q000628:therapy; D002294:Carcinoma, Squamous Cell / Q000150:complications / Q000401:mortality / Q000473:pathology / Q000628:therapy; D059248:Chemoradiotherapy / Q000401:mortality*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000150:complications* / Q000401:mortality / Q000473:pathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000150:complications* / Q000401:mortality / Q000473:pathology / Q000628:therapy; D009367:Neoplasm Staging; D011379:Prognosis; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D020266:Radiotherapy, Conformal; D012189:Retrospective Studies; D015996:Survival Rate; D014057:Tomography, X-Ray Computed