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The role of parotid gland irradiation in the development of severe hyposalivation (xerostomia) after intensity-modulated radiation therapy for head and neck cancer: Temporal patterns, risk factors, and testing the QUANTEC guidelines.
- Source :
- Journal of Cranio-Maxillofacial Surgery; Apr2017, Vol. 45 Issue 4, p595-600, 6p
- Publication Year :
- 2017
-
Abstract
- Background The aims of this study were to investigate temporal patterns and potential risk factors for severe hyposalivation (xerostomia) after intensity-modulated radiotherapy (IMRT) for head and neck cancer (HNC), and to test the two QUANTEC (Quantitative Analysis of Normal Tissue Effects in the Clinic) guidelines. Patients and methods Sixty-three patients treated at the Memorial Sloan Kettering Cancer Center between 2006 and 2015, who had a minimum of three stimulated whole mouth saliva flow measurements (WMSFM) at a median follow-up time of 11 (range: 3–24) months were included. Xerostomia was defined as WMSFM ≤25% compared to relative pre-radiotherapy. Patients were stratified into three follow-up groups: 1: <6 months; 2: 6–11 months; and 3: 12–24 months. Potential risk factors were investigated (Mann–Whitney U test), and relative risks (RRs) assessed for the two QUANTEC guidelines. Results The incidence of xerostomia was 27%, 14% and 17% at follow-up time points 1, 2 and 3, respectively. At <6 months, the mean dose to the contralateral and the ipsilateral parotid glands (Dmean contra , Dmean ipsi ) was higher among patients with xerostomia (Dmean contra : 25 Gy vs. 15 Gy; Dmean ipsi : 44 Gy vs. 25 Gy). Patients with xerostomia had higher pre-RT WMSFM (3.5 g vs. 2.4 g), and had been treated more frequently with additional chemotherapy (93% vs. 63%; all 4 variables: p < 0.05). At 6–11 months, Dmean contra among patients with xerostomia was higher compared to patients without (26 Gy vs. 20 Gy). The RR as specified by the one- and two-gland QUANTEC guideline was 2.3 and 1.4 for patients with <6 months follow-up time, and 2.0 and 1.2 for patients with longer follow-up (6–11 + 6–24 months). Conclusion Xerostomia following IMRT peaks within six months post-radiotherapy and fades with time. Limiting the mean dose to both parotid glands (ipsilateral <25 Gy, contralateral <25 Gy) and reducing the use of chemotherapy will likely decrease the rate of xerostomia. Both QUANTEC guidelines are effective in preventing xerostomia. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 10105182
- Volume :
- 45
- Issue :
- 4
- Database :
- Supplemental Index
- Journal :
- Journal of Cranio-Maxillofacial Surgery
- Publication Type :
- Academic Journal
- Accession number :
- 122039630
- Full Text :
- https://doi.org/10.1016/j.jcms.2017.01.020