title: Normal Tissue Complication Probability Model for Radiation-induced Temporal Lobe Injury after Intensity-modulated Radiation Therapy for Nasopharyngeal Carcinoma.
abstract: OBJECTIVE
  To identify predictors for the development of temporal lobe injury (TLI) after intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma.
  
  
  METHODS
  Data in 351 patients with nasopharyngeal carcinoma treated with IMRT were reviewed retrospectively according to institutional ethics committee approval. Clinical factors associated with TLI were analyzed. Dose-volume histograms for 550 evaluable temporal lobes were analyzed, and the predictive value of therapy-associated and patient-associated factors for the occurrence of TLI was evaluated. Survival curves were depicted by using the Kaplan-Meier method and compared by using the log-rank test. Logistic regression analysis was used for multivariate analyses.
  
  
  RESULTS
  Median follow-up was 76 months (range, 6-100 months). Twenty-nine of 351 patients (8.3%) developed TLI; 21 patients had unilateral TLI, and eight had bilateral TLI. Median latency from IMRT until first TLI was 33 months (range, 12-83 months) among patients with TLI. The actuarial TLI-free survival rates were 94.4% and 91.3% at 3 and 5 years after radiation therapy, respectively. Logistic regression analysis demonstrated that dose delivered to a 1-cm(3) volume of the temporal lobe (D1cc) was the only independent predictor for TLI. The biologically equivalent tolerance doses at 2 Gy for a 5% and 50% probability of developing TLI were 62.83-Gy equivalents (95% confidence interval: 59.68, 65.97) and 77.58-Gy equivalents (95% confidence interval: 74.85, 80.32), respectively.
  
  
  CONCLUSIONS
  D1cc is predictive for radiation-induced TLI, suggesting that delivery of a high dose of radiation to a small volume of the temporal lobe is unsafe. A D1cc of 62.83 Gy by using a correction formula for varying fraction size may be the dose tolerance of the temporal lobe.
authors: From State Key Laboratory Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangzhou, People's Republic of China (L.Z., S.M.H., Y.M.T., X.M.S., F.H., T.X.L., X.W.D.); Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, 651 Dong Feng Road East, Guangzhou 510060, Guangdong Province, People's Republic of China (L.Z., S.M.H., Y.M.T., X.M.S., F.H., T.X.L., X.W.D.); and Department of Radiation Oncology, Jiangxi Cancer Hospital, Nanchang, People's Republic of China (L.Z.).
authors: Lei
authors: L
authors: Zeng
authors: From State Key Laboratory Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangzhou, People's Republic of China (L.Z., S.M.H., Y.M.T., X.M.S., F.H., T.X.L., X.W.D.); Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, 651 Dong Feng Road East, Guangzhou 510060, Guangdong Province, People's Republic of China (L.Z., S.M.H., Y.M.T., X.M.S., F.H., T.X.L., X.W.D.); and Department of Radiation Oncology, Jiangxi Cancer Hospital, Nanchang, People's Republic of China (L.Z.).
authors: Shao-Min
authors: SM
authors: Huang
authors: From State Key Laboratory Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangzhou, People's Republic of China (L.Z., S.M.H., Y.M.T., X.M.S., F.H., T.X.L., X.W.D.); Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, 651 Dong Feng Road East, Guangzhou 510060, Guangdong Province, People's Republic of China (L.Z., S.M.H., Y.M.T., X.M.S., F.H., T.X.L., X.W.D.); and Department of Radiation Oncology, Jiangxi Cancer Hospital, Nanchang, People's Republic of China (L.Z.).
authors: Yun-Ming
authors: YM
authors: Tian
authors: From State Key Laboratory Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangzhou, People's Republic of China (L.Z., S.M.H., Y.M.T., X.M.S., F.H., T.X.L., X.W.D.); Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, 651 Dong Feng Road East, Guangzhou 510060, Guangdong Province, People's Republic of China (L.Z., S.M.H., Y.M.T., X.M.S., F.H., T.X.L., X.W.D.); and Department of Radiation Oncology, Jiangxi Cancer Hospital, Nanchang, People's Republic of China (L.Z.).
authors: Xue-Ming
authors: XM
authors: Sun
authors: From State Key Laboratory Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangzhou, People's Republic of China (L.Z., S.M.H., Y.M.T., X.M.S., F.H., T.X.L., X.W.D.); Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, 651 Dong Feng Road East, Guangzhou 510060, Guangdong Province, People's Republic of China (L.Z., S.M.H., Y.M.T., X.M.S., F.H., T.X.L., X.W.D.); and Department of Radiation Oncology, Jiangxi Cancer Hospital, Nanchang, People's Republic of China (L.Z.).
authors: Fei
authors: F
authors: Han
authors: From State Key Laboratory Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangzhou, People's Republic of China (L.Z., S.M.H., Y.M.T., X.M.S., F.H., T.X.L., X.W.D.); Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, 651 Dong Feng Road East, Guangzhou 510060, Guangdong Province, People's Republic of China (L.Z., S.M.H., Y.M.T., X.M.S., F.H., T.X.L., X.W.D.); and Department of Radiation Oncology, Jiangxi Cancer Hospital, Nanchang, People's Republic of China (L.Z.).
authors: Tai-Xiang
authors: TX
authors: Lu
authors: From State Key Laboratory Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangzhou, People's Republic of China (L.Z., S.M.H., Y.M.T., X.M.S., F.H., T.X.L., X.W.D.); Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, 651 Dong Feng Road East, Guangzhou 510060, Guangdong Province, People's Republic of China (L.Z., S.M.H., Y.M.T., X.M.S., F.H., T.X.L., X.W.D.); and Department of Radiation Oncology, Jiangxi Cancer Hospital, Nanchang, People's Republic of China (L.Z.).
authors: Xiao-Wu
authors: XW
authors: Deng
mesh_terms: D000328:Adult; D002277:Carcinoma; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000209:etiology*; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*; D012189:Retrospective Studies; D013702:Temporal Lobe / Q000293:injuries*