The impact of reduced-volume, intensity-modulated radiation therapy on disease control in nasopharyngeal carcinoma.
OBJECTIVE
To investigate the feasibility of using intensity-modulated radiotherapy (IMRT) with reduced, high-dose target volumes for nasopharyngeal carcinoma (NPC).


METHODS
The first 57 patients (admitted from October 2005 to May 2008) were treated with large-target-volume IMRT (LV-IMRT). For the LV-IMRT group, the CTV at 70 Gy (CTV70) was delineated as the gross target volume (GTV) plus 7mm, with or without the first-echelon lymph-node region. The next 56 patients (admitted from June 2008 to November 2011) were treated with reduced-target-volume IMRT (RV-IMRT). For the RV-IMRT group, the CTV70 was delineated as the GTV alone.


RESULTS
The 4-year local recurrence-free, regional recurrence-free, distant metastasis-free, progression-free, and overall survival rates were 77.2%, 80.1%, 83.2%, 61.2%, and 74.4% for the LV-IMRT group and 83.5%, 92.6%, 89.1%, 78.5, and 91.0% for the RV-IMRT group, respectively. Late toxicity scoring of xerostomia was lesser in the RV-IMRT group than the LV-IMRT group (P < 0.001).


CONCLUSIONS
The use of RV-IMRT for the treatment of NPC did not negatively affect survival rates but did reduce the late xerostomia events compared to LV-IMRT.
Department of Radiation Oncology, Chi Mei Medical Center, Tainan, Taiwan; Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan; The School of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
Yu-Wei
YW
Lin
Department of Radiation Oncology, Liouying campus, Chi Mei Medical Center, Tainan, Taiwan.
Chia-Chun
CC
Chen
Department of Radiation Oncology, Chi Mei Medical Center, Tainan, Taiwan; School of Medicine, Taipei Medical University, Taipei, Taiwan.
Li-Ching
LC
Lin
Department of Radiation Oncology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States of America; Department of Radiation Oncology, VA Greater Los Angeles Healthcare System, Los Angeles, CA, United States of America.
Steve P
SP
Lee
D002277:Carcinoma; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000532:radiotherapy*; D016016:Proportional Hazards Models; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects / Q000379:methods*; D012307:Risk Factors; D016879:Salvage Therapy; D017211:Treatment Failure