Email updates

Keep up to date with the latest news and content from BMC Cancer and BioMed Central.

Open Access Research article

Radiation-induced temporal lobe injury after intensity modulated radiotherapy in nasopharyngeal carcinoma patients: a dose-volume-outcome analysis

Ying Sun1, Guan-Qun Zhou1, Zhen-Yu Qi1, Li Zhang1, Shao-Min Huang1, Li-Zhi Liu2, Li Li2, Ai-Hua Lin3 and Jun Ma1*

Author Affiliations

1 State Key Laboratory of Oncology in Southern China, Department of Radiation Oncology, Cancer Center, Sun Yat-sen University, Guangzhou 510060, People’s Republic of China

2 State Key Laboratory of Oncology in Southern China, Imaging Diagnosis and Interventional Center, Cancer Center, Sun Yat-sen University, Guangzhou 510060, People’s Republic of China

3 Department of Medical Statistics and Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou 510060, People’s Republic of China

For all author emails, please log on.

BMC Cancer 2013, 13:397  doi:10.1186/1471-2407-13-397

Published: 27 August 2013

Abstract

Background

To identify the radiation volume effect and significant dosimetric parameters for temporal lobe injury (TLI) and determine the radiation dose tolerance of the temporal lobe (TL) in nasopharyngeal carcinoma (NPC) patients treated with intensity modulated radiation therapy (IMRT).

Methods

Twenty NPC patients with magnetic resonance imaging (MRI)-diagnosed unilateral TLI were reviewed. Dose-volume data was retrospectively analyzed.

Results

Paired samples t-tests showed all dosimetric parameters significantly correlated with TLI, except the TL volume (TLV) and V75 (the TLV that received ≥75 Gy, P = 0.73 and 0.22, respectively). Receiver operating characteristic (ROC) curves showed V10 and V20 (P = 0.552 and 0.11, respectively) were the only non-significant predictors from V10 to V70 for TLI. D0.5cc (dose to 0.5 ml of the TLV) was an independent predictor for TLI (P < 0.001) in multivariate analysis; the area under the ROC curve for D0.5cc was 0.843 (P < 0.001), and the cutoff point 69 Gy was deemed as the radiation dose limit. The distribution of high dose ‘hot spot’ regions and the location of TLI were consistent.

Conclusions

A D0.5cc of 69 Gy may be the dose tolerance of the TL. The risk of TLI was highly dependent on high dose ‘hot spots’ in the TL; physicians should be cautious of such ‘hot spots’ in the TL during IMRT treatment plan optimization, review and approval.

Keywords:
Nasopharyngeal carcinoma; Temporal lobe injury; Intensity modulated radiotherapy; Radiation volume effect; Dose tolerance