title: Radiation-induced temporal lobe injury for nasopharyngeal carcinoma: a comparison of intensity-modulated radiotherapy and conventional two-dimensional radiotherapy.
abstract: BACKGROUND
  To compare the radiation-induced temporal lobe injury (TLI) in patients with nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiotherapy (IMRT) or two-dimensional conventional radiotherapy (2D-CRT).
  
  
  METHODS
  1276 cases of NPC treated with IMRT or 2D-CRT were retrospectively reviewed. A diagnosis of TLI was made on follow-up magnetic resonance imaging (MRI).
  
  
  RESULTS
  The crude incidence of TLI was 7.5% and 10.8% (P = 0.048), and the actuarial 5-year incidence was 16% and 34.9% (P<0.001) for the IMRT and 2D-CRT groups, respectively. Multivariate analysis revealed both T stage (P<0.001) and radiation technique (P<0.001) as independent predictors. Patients with T1, T2 and T3 disease had a significantly higher risk when treated with 2D-CRT (P = 0.005, 0.016, <0.001, respectively). This trend was not evident for T4 patients (P = 0.680). The 2D-CRT group had a longer latency for the development of TLI (P<0.001). Those with T4 disease had a shorter median time to TLI (P = 0.006, 0.042, <0.001 when compared with T1, T2 and T3, respectively).
  
  
  CONCLUSIONS
  IMRT is superior to 2DRT for the management of T1-T3 NPC in terms of sparing the temporal lobe. The high incidence of TLI in T4 disease needs to be addressed.
authors.affiliation: State Key Laboratory of Oncology in Southern China, Department of Radiation Oncology, Cancer Center, Sun Yat-sen University, Guangzhou, People's Republic of China.
authors.forename: Guan-Qun
authors.initials: GQ
authors.lastname: Zhou
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Yu
authors.forename: Mo
authors.initials: M
authors.lastname: Chen
authors.forename: Rui
authors.initials: R
authors.lastname: Guo
authors.forename: Ying
authors.initials: Y
authors.lastname: Lei
authors.forename: Ying
authors.initials: Y
authors.lastname: Sun
authors.forename: Yan-Ping
authors.initials: YP
authors.lastname: Mao
authors.forename: Li-Zhi
authors.initials: LZ
authors.lastname: Liu
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.forename: Ai-Hua
authors.initials: AH
authors.lastname: Lin
authors.forename: Jun
authors.initials: J
authors.lastname: Ma
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002277:Carcinoma; D002648:Child; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000453:epidemiology / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000453:epidemiology / Q000209:etiology*; D020266:Radiotherapy, Conformal / Q000009:adverse effects*; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*; D012189:Retrospective Studies; D013702:Temporal Lobe / Q000293:injuries* / Q000528:radiation effects; D055815:Young Adult