Abstract
5501 Background: Severe xerostomia regularly occurs in NPC patients treated by 2-dimensional radiotherapy (2DRT). Although IMRT reduces parotid gland irradiation in NPC, randomized data supporting its use is lacking. Methods: Patients with T1–2bN0–2M0 NPC were randomized to receive either IMRT or 2DRT, both 66Gy, without chemotherapy. Primary endpoint was RTOG xerostomia at 1 year after treatment. Secondary endpoints included RTOG xerostomia at 6 weeks post treatment, stimulated parotid flow rate (SPFR) and stimulated whole saliva flow rate (SWSFR). Post-RT saliva flow rate was expressed as percentage of residual flow rate over pre-RT baseline. Planned sample size was 27 patients in each arm, to detect a 40% reduction in incidence of severe (RTOG >=grade 2) xerostomia (assumed to occur in >=80% of 2DRT-treated patients) with 80% power for alpha=0.05. Categorical and continuous variables were analyzed with chi-square test and wilcoxon rank-sum test, respectively. Results: 60 patients were recruited, and 56 patients were eligible (28 patients in each arm). Patients in IMRT arm had significantly less severe xerostomia than 2DRT at 6 weeks (13/28 vs 24/28, p=0.0019), and a borderline difference at 6 months (21/28 vs 26/28, p=0.0689) after RT. Post-RT SPFR was significantly higher in IMRT arm at 6 weeks (39% vs 9%, p<0.0001) and at 6 months (70% vs 4%, p<0.0001). Post-RT SWSFR was similar between both arms at 6 weeks and at 6 months. Analysis of 1-year data would be performed in March. No failure or death was observed in either arm. Conclusions: IMRT is superior to 2DRT in preserving parotid function and results in less severe xerostomia as early as 6 weeks post-RT. SPFR, but not SWSFR, shows progressive recovery over time with IMRT. (This study is supported by Hong Kong Research Grant Council CUHK4041/01M) No significant financial relationships to disclose.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
