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Patient- and therapy-related factors associated with the incidence of xerostomia in nasopharyngeal carcinoma patients receiving parotid-sparing helical tomotherapy.

Lee TF, Liou MH, Ting HM, Chang L, Lee HY, Wan Leung S, Huang CJ, Chao PJ - Sci Rep (2015)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Medical Physics and Informatics Laboratory of Electronics Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 80778, Taiwan, ROC.

ABSTRACT
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.

No MeSH data available.


Related in: MedlinePlus

The isodose distributions on transverse, coronal, and sagittal views for one representative nasopharyngeal carcinoma case planned by helical tomotherapy using PET/CT image sets. (a) At the nasopharyngeal region. (b) At the upper neck region near the parotid glands. (c) At the upper neck region near the submandibular glands. (d) Coronal view. (e) Sagittal view.
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f1: The isodose distributions on transverse, coronal, and sagittal views for one representative nasopharyngeal carcinoma case planned by helical tomotherapy using PET/CT image sets. (a) At the nasopharyngeal region. (b) At the upper neck region near the parotid glands. (c) At the upper neck region near the submandibular glands. (d) Coronal view. (e) Sagittal view.

Mentions: For all of the patients in this study, the HT plans achieved comparable PTV coverage, and the dose-prescription policies were based on the percentage of the prescribed dose that covered >95% of the PTV, and was also equivalent in sparing sensitive structures (parotid glands, submandibular glands, and oral cavity). The isodose distribution of a typical HT NPC patient is shown in Fig. 1. The scatter plots of the mean dose to the parotid glands and submandibular glands for the NPC cohorts are shown in Fig. 2(a–d); additionally, the differences in dose distributions to the oral cavity are shown in Fig. 2(e,f). At 1 month after treatment, 50% (27/54) of the NPC patients reported moderate to severe xerostomia. At 6 months after treatment, 27.8% (15/54) of the patients reported moderate to severe xerostomia, as shown in Table 1. (x /x = number of patient with moderate to severe xerostomia/ whole study cohort).


Patient- and therapy-related factors associated with the incidence of xerostomia in nasopharyngeal carcinoma patients receiving parotid-sparing helical tomotherapy.

Lee TF, Liou MH, Ting HM, Chang L, Lee HY, Wan Leung S, Huang CJ, Chao PJ - Sci Rep (2015)

The isodose distributions on transverse, coronal, and sagittal views for one representative nasopharyngeal carcinoma case planned by helical tomotherapy using PET/CT image sets. (a) At the nasopharyngeal region. (b) At the upper neck region near the parotid glands. (c) At the upper neck region near the submandibular glands. (d) Coronal view. (e) Sagittal view.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4542473&req=5

f1: The isodose distributions on transverse, coronal, and sagittal views for one representative nasopharyngeal carcinoma case planned by helical tomotherapy using PET/CT image sets. (a) At the nasopharyngeal region. (b) At the upper neck region near the parotid glands. (c) At the upper neck region near the submandibular glands. (d) Coronal view. (e) Sagittal view.
Mentions: For all of the patients in this study, the HT plans achieved comparable PTV coverage, and the dose-prescription policies were based on the percentage of the prescribed dose that covered >95% of the PTV, and was also equivalent in sparing sensitive structures (parotid glands, submandibular glands, and oral cavity). The isodose distribution of a typical HT NPC patient is shown in Fig. 1. The scatter plots of the mean dose to the parotid glands and submandibular glands for the NPC cohorts are shown in Fig. 2(a–d); additionally, the differences in dose distributions to the oral cavity are shown in Fig. 2(e,f). At 1 month after treatment, 50% (27/54) of the NPC patients reported moderate to severe xerostomia. At 6 months after treatment, 27.8% (15/54) of the patients reported moderate to severe xerostomia, as shown in Table 1. (x /x = number of patient with moderate to severe xerostomia/ whole study cohort).

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Medical Physics and Informatics Laboratory of Electronics Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 80778, Taiwan, ROC.

ABSTRACT
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.

No MeSH data available.


Related in: MedlinePlus