Prospective randomized study of intensity-modulated radiotherapy on salivary gland function in early-stage nasopharyngeal carcinoma patients.
OBJECTIVE
This randomized trial compared the rates of delayed xerostomia between two-dimensional radiation therapy (2DRT) and intensity-modulated radiation therapy (IMRT) in the treatment of early-stage nasopharyngeal carcinoma (NPC).


METHODS
Between November 2001 and December 2003, 60 patients with T1-2bN0-1M0 NPC were randomly assigned to receive either IMRT or 2DRT. Primary end point was incidence of observer-rated severe xerostomia at 1 year after treatment based on Radiotherapy Oncology Group /European Organisation for the Research and Treatment of Cancer late radiation morbidity scoring criteria. Parallel assessment with patient-reported outcome, stimulated parotid flow rate (SPFR), and stimulated whole saliva flow rate (SWSFR) were also made.


RESULTS
At 1 year after treatment, patients in IMRT arm had lower incidence of observer-rated severe xerostomia than patients in the 2DRT arm (39.3% v 82.1%; P = .001), parallel with a higher fractional SPFR (0.90 v 0.05; P < .0001), and higher fractional SWSFR (0.41 v 0.20; P = .001). As for patient's subjective feeling, although a trend of improvement in patient-reported outcome was observed after IMRT, recovery was incomplete and there was no significant difference in patient-reported outcome between the two arms.


CONCLUSIONS
IMRT is superior to 2DRT in preserving parotid function and results in less severe delayed xerostomia in the treatment of early-stage NPC. Incomplete improvement in patient's subjective xerostomia with parotid-sparing IMRT reflects the need to enhance protection of other salivary glands.
Kam
Michael K M
MK
State Key Laboratory in Oncology in South China, Sir Y.K. Pao Centre for Cancer, Department of Clinical Oncology, Hong Kong Cancer Institute, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.
Leung
Sing-Fai
SF
Zee
Benny
B
Chau
Ricky M C
RM
Suen
Joyce J S
JJ
Mo
Frankie
F
Lai
Maria
M
Ho
Rosalie
R
Cheung
Kin-yin
KY
Yu
Brian K H
BK
Chiu
Samuel K W
SK
Choi
Peter H K
PH
Teo
Peter M L
PM
Kwan
Wing-hong
WH
Chan
Anthony T C
AT
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000532:radiotherapy*; D011446:Prospective Studies; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects; D012469:Salivary Glands / Q000503:physiopathology / Q000528:radiation effects*; D014987:Xerostomia / Q000453:epidemiology / Q000209:etiology