Patient- and therapy-related factors associated with the incidence of xerostomia in nasopharyngeal carcinoma patients receiving parotid-sparing helical tomotherapy.
We investigated the incidence of moderate to severe patient-reported xerostomia among nasopharyngeal carcinoma (NPC) patients treated with helical tomotherapy (HT) and identified patient- and therapy-related factors associated with acute and chronic xerostomia toxicity. The least absolute shrinkage and selection operator (LASSO) normal tissue complication probability (NTCP) models were developed using quality-of-life questionnaire datasets from 67 patients with NPC. For acute toxicity, the dosimetric factors of the mean doses to the ipsilateral submandibular gland (Dis) and the contralateral submandibular gland (Dcs) were selected as the first two significant predictors. For chronic toxicity, four predictive factors were selected: age, mean dose to the oral cavity (Doc), education, and T stage. The substantial sparing data can be used to avoid xerostomia toxicity. We suggest that the tolerance values corresponded to a 20% incidence of complications (TD20) for Dis = 39.0 Gy, Dcs = 38.4 Gy, and Doc = 32.5 Gy, respectively, when mean doses to the parotid glands met the QUANTEC 25 Gy sparing guidelines. To avoid patient-reported xerostomia toxicity, the mean doses to the parotid gland, submandibular gland, and oral cavity have to meet the sparing tolerance, although there is also a need to take inherent patient characteristics into consideration.
Medical Physics and Informatics Laboratory of Electronics Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 80778, Taiwan, ROC.|Graduate Institute of Clinical Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan, ROC.
Tsair-Fwu
TF
Lee
Department of Electrical Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 80778, Taiwan, ROC.|Department of Radiation Oncology, Kaohsiung Yuan's General Hospital, Kaohsiung 80249, Taiwan, ROC.
Ming-Hsiang
MH
Liou
Medical Physics and Informatics Laboratory of Electronics Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 80778, Taiwan, ROC.|Department of Radiation Oncology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 83342, Taiwan, ROC.
Hui-Min
HM
Ting
Department of Medical Imaging and Radiological Sciences, I-Shou University, Kaohsiung 82445, Taiwan, ROC.
Liyun
L
Chang
Department of Electrical Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 80778, Taiwan, ROC.
Hsiao-Yi
HY
Lee
Department of Radiation Oncology, Kaohsiung Yuan's General Hospital, Kaohsiung 80249, Taiwan, ROC.
Stephen
S
Wan Leung
Department of Radiation Oncology, Kaohsiung Medical University Chung-Ho Memorial Hospital, Kaohsiung 807, Taiwan, ROC.
Chih-Jen
CJ
Huang
Medical Physics and Informatics Laboratory of Electronics Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 80778, Taiwan, ROC.|Department of Radiation Oncology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 83342, Taiwan, ROC.
Pei-Ju
PJ
Chao
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000532:radiotherapy*; D059351:Organ Sparing Treatments; D010306:Parotid Gland / Q000473:pathology*; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*; D014987:Xerostomia / Q000453:epidemiology* / Q000209:etiology*; D055815:Young Adult