Late toxicities after intensity-modulated radiotherapy for nasopharyngeal carcinoma: patient and treatment-related risk factors

• Published in: British journal of cancer Vol. 110; no. 1; pp. 49 - 54
• Main Authors: Zeng, L, Tian, Y-M, Sun, X-M, Chen, C-Y, Han, F, Xiao, W-W, Deng, X-W, Lu, T-X
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 07-01-2014; Nature Publishing Group
• Subjects: 692/499; 692/699/67/1059/485; 692/699/67/1059/99; 692/699/67/1536; Adolescent; Adult; Aged; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Cancer Research; Cancer therapies; Carcinoma; Chemotherapy; China - epidemiology; Clinical Study; Dose-Response Relationship, Radiation; Drug Resistance; Epidemiology; Female; Humans; Male; Medical sciences; Middle Aged; Molecular Medicine; Multiple tumors. Solid tumors. Tumors in childhood (general aspects); Nasopharyngeal Carcinoma; Nasopharyngeal Neoplasms - epidemiology; Nasopharyngeal Neoplasms - pathology; Nasopharyngeal Neoplasms - radiotherapy; Neoplasm Staging; Oncology; Otorhinolaryngology. Stomatology; Patients; Radiation Injuries - epidemiology; Radiation Injuries - etiology; Radiation therapy; Radiotherapy, Intensity-Modulated - adverse effects; Radiotherapy, Intensity-Modulated - statistics & numerical data; Retrospective Studies; Toxicity; Tumors; Upper respiratory tract, upper alimentary tract, paranasal sinuses, salivary glands: diseases, semeiology; Young Adult; China; nasopharyngeal carcinoma; intensity-modulated radiotherapy; temporal lobe injury; chemotherapy; late toxicity; Human; Temporal lobe; Late; Nasopharynx cancer; Toxicity; Malignant tumor; Nasopharynx carcinoma; Epidemiology; Chemotherapy; Intensity modulated radiotherapy; Cancerology; Treatment; Risk factor; ENT disease; Pharynx disease; Lesion; Cancer
• ISSN: 0007-0920; 1532-1827
• DOI: 10.1038/bjc.2013.720

Background:
The objective of this study is to analyse the factors affecting late toxicity for nasopharyngeal carcinoma (NPC) patients treated with intensity-modulated radiotherapy (IMRT).
Methods:
Seven hundred and eighty-nine consecutive NPC patients treated with IMRT at our centre from January 2003 to February 2008 were retrospectively analysed. Radiotherapy-related complications were categorised using the RTOG Late Radiation Morbidity Scoring Criteria and the Common Terminology Criteria for Adverse Events (Version 3.0). Two hundred and thirty-three patients were treated with IMRT alone (group 1) and 556 patients underwent cisplatin-based chemotherapy (group 2).
Results:
Median follow-up was 65 months (range, 4–106 months). The 5-year major late toxicity rate was significantly greater in group 2 than group 1 (63.2%
vs
42.0%,
P
<0.001). Multivariate analyses showed that N category, T category and chemotherapy were significant factors. The maximal dose (Dmax) to the temporal lobe was a significant factor affecting temporal lobe injury (TLI), with a hazard ratio of 1.26 (95% confidence interval (CI), 1.18–1.35;
P
<0.001) per 1-Gy increase. The 5-year TLI rate increased from 0.8% for 284 lobes with Dmax <65.77 Gy to 27.1% for 176 lobes with greater doses (
P
<0.001). Logistic regression showed that the hazard ratio attributed to the parotid gland mean dose was 1.36 (95% CI, 1.21–1.53;
P
<0.001) per 1-Gy increase. Chemotherapy was not a significant factor (
P
=0.211).
Conclusion:
With the application of IMRT, the incidence of radiation-related complications has been reduced except for TLI. The significant factors affecting the risk of TLI included T category, chemotherapy and Dmax.