Clinical and dosimetric predictors of physician and patient reported xerostomia following intensity modulated radiotherapy for nasopharyngeal cancer - A prospective cohort analysis.
BACKGROUND AND PURPOSE
To compare physician and patient reported xerostomia and correlate xerostomia with dosimetric and clinical parameters for nasopharyngeal cancer (NPC) patients treated with intensity modulated radiotherapy (IMRT) and chemotherapy.


PATIENTS AND METHODS
We analyzed the data of 172 patients with locally advanced NPC. Xerostomia was evaluated via physician-rated xerostomia based on RTOG morbidity score (E1), patient-rated dry mouth (E2) and patient-rated sticky saliva (E3) based on EORTC QLQ-HN35 questionnaire. Primary endpoint was the presence of moderate to severe xerostomia at 2-year after completion of IMRT.


RESULTS
The levels of physician reported xerostomia (E1) were consistently lower than patient reported dry mouth (E2) over time. The incidence of patients with xerostomia at 3-month post RT was 58% based on E1, 70% based on E2, and 51% based on E3. The corresponding incidence rates at 2-year post RT was 26% (E1), 36% (E2) and 21% (E3). The incidence of patients with xerostomia at 1-year post RT was close to that at 2-year post RT for all the 3 endpoints. The average Dmean of parotid glands was 41.5 Gy (range: 31.0 Gy-65.9 Gy, median: 40.7 Gy). No dosimetric parameters were significantly associated with xerostomia.


CONCLUSION
Significant proportion of patients still experienced long term xerostomia with IMRT. Dose-effect relationships between xerostomia and the parotid glands were not observed in this study.
['Sommat|Kiattisa|K|', 'Hussain|Ashik|A|', 'Ong|Whee Sze|WS|', 'Yit|Nelson Ling Fung|NLF|', 'Khoo|James Boon Kheng|JBK|', 'Soong|Yoke Lim|YL|', 'Wee|Joseph Tien Seng|JTS|', 'Fong|Kam Weng|KW|', 'Tan|Terence Wee Kiat|TWK|']
D000328:Adult D000368:Aged D017322:Clinical Trials, Phase II as Topic D017326:Clinical Trials, Phase III as Topic D015331:Cohort Studies D004307:Dose-Response Relationship, Radiation D005260:Female D006801:Humans D008297:Male D008875:Middle Aged D000077274:Nasopharyngeal Carcinoma D009303:Nasopharyngeal Neoplasms D010306:Parotid Gland D000071066:Patient Reported Outcome Measures D011446:Prospective Studies D011832:Radiation Injuries D050397:Radiotherapy, Intensity-Modulated D016032:Randomized Controlled Trials as Topic D011795:Surveys and Questionnaires D014987:Xerostomia D055815:Young Adult
Xerostomia Intensity modulated radiotherapy Nasopharyngeal carcinoma