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Abstract Background The salivary mucin MUC5B, present in (sero)mucous secretions including submandibular gland (SMG) saliva, plays an important role in the lubrication of the oral mucosa and is thought to be related to the feeling of dry mouth. We investigated if MUC5B levels in SMG saliva could distinguish between the presence or absence of severe dry mouth complaints 12 months after radiotherapy (RT) for head-and-neck cancer (HNC). Findings Twenty-nine HNC patients with a residual stimulated SMG secretion rate of ≥0.2 ml/10 min at 12 months after RT were analyzed. MUC5B (in U; normalized to 1) and total protein levels (mg/ml) were measured in SMG saliva at baseline and 12 months after RT using ELISA and BCA protein assay, respectively. Overall, median MUC5B levels decreased after RT from 0.12 to 0.03 U (p = 0.47). Patients were dichotomized into none/mild xerostomia (n = 12) and severe xerostomia (n = 17) based on a questionnaire completed at 12 months. SMG and whole saliva flow rates decreased after RT but were comparable in both groups. The median MUC5B level was higher in patients with no or mild xerostomia compared to patients with severe xerostomia (0.14 vs 0.01 U, p = 0.22). Half of the patients with severe xerostomia had no detectable MUC5B at 12 months after RT. No differences in total protein levels were observed. Conclusions Qualitative saliva parameters like MUC5B need further investigation in RT-induced xerostomia. This pilot study showed a trend towards lower MUC5B levels in the SMG saliva of patients with severe xerostomia 12 months after RT for HNC.

Background: GTV delineation is the first crucial step in radiotherapy and requires high accuracy, especially with the growing use of highly conformal and adaptive radiotherapy techniques. If GTV delineations of observers concord, they are considered to be of high accuracy. The aim of the study is to determine the interobserver agreement for GTV delineations of supraglottic laryngeal carcinoma on CT and on CT combined with MR-images and to determine the effect of adding MR images to CT-based delineation on the delineated volume and the interobserver agreement. Methods: Twenty patients with biopsy proven T1-T4 supraglottic laryngeal cancer, treated with curative intent were included. For all patients a contrast enhanced planning CT and a 1.5-T MRI with gadolinium were acquired in the same head-and-shoulder mask for fixation as used during treatment. For MRI, a two element surface coil was used as a receiver coil. Three dedicated observers independently delineated the GTV on CT. After an interval of 2 weeks, a set of co-registered CT and MR-images was provided to delineate the GTV on CT. Common volumes (C) and encompassing volumes (E) were calculated and C/E ratios were determined for each pair of observers. The conformity index general (CIgen) was used to quantify the interobserver agreement. Results: In general, a large variation in interobserver agreement was found for CT (range: 0.29-0.77) as well as for CT-MR delineations (range: 0.17-0.80). The mean CIgen for CT (0.61) was larger compared to CT-MR (0.57) (p = 0.032). Mean GTV volume delineated on CT-MR (6.6 cm³) was larger compared to CT (5.6 cm³) (p = 0.002). Conclusion: Delineation on CT with co-registered MR-images resulted in a larger mean GTV volume and in a decrease in interobserver agreement compared to CT only delineation for supraglottic laryngeal carcinoma. [ABSTRACT FROM AUTHOR]

Background and purpose: Since lymph nodes volumes are generally four times the volume of the primary PTV, the advantage of using tight margins around the primary PTV is not clear. Therefore treatment margins of T2-T4 laryngeal carcinoma for IMRT are generally chosen in such a way that the PTV is comparable to that in conventional radiotherapy. The aim of this study is to quantify the effect of volume reduction of the primary PTV of T2-T4 laryngeal carcinoma with regard to late toxicity despite elective irradiation of lymph node levels II to IV. Methods: Two treatment plans based on conservative (GTV-PTV = 15 mm and 20 mm cranial), and on evidence-based tight margins (GTV-PTV = 8 mm) were calculated for 16 patients. Toxicity effects were estimated based on the dose distributions. Results: Compared to conservative margins, using tight margins resulted in: 1) significant reduction of the normal tissue complication probability (NTCP) for swallowing muscles and submandibular glands, 2) significant reduction of the mean dose in all organs at risk (OAR), 3) a mean dose smaller than 60 Gy for all OARs except for the laryngeal cartilages. When the lymph node levels II to IV were prescribed with an elective dose, an NTCP reduction of 53% for the swallowing muscles and of 23% for the submandibular glands was found by using tight instead of conservative margins. When positive nodes were present, NTCP reduction amounted to 29% and 15%, respectively. Conclusions: There is a potential benefit in realizing evidence-based tight margins for laryngeal cancer patients despite elective irradiation of lymph node levels II to IV. [ABSTRACT FROM AUTHOR]

Background: To describe long-term changes in time of quality of life (QOL) and the relation with parotid salivary output in patients with head-and-neck cancer treated with radiotherapy. Methods: Forty-four patients completed the EORTC-QLQ-C30(+3) and the EORTC-QLQH& N35 questionnaires before treatment, 6 weeks, 6 months, 12 months, and at least 3.5 years after treatment. At the same time points, stimulated bilateral parotid flow rates were measured. Results: There was a deterioration of most QOL items after radiotherapy compared with baseline, with gradual improvement during 5 years follow-up. The specific xerostomia-related items showed improvement in time, but did not return to baseline. Global QOL did not alter significantly in time, although 41% of patients complained of moderate or severe xerostomia at 5 years followup. Five years after radiotherapy the mean cumulated parotid flow ratio returned to baseline but 20% of patients had a flow ratio <25%. The change in time of xerostomia was significantly related with the change in flow ratio (p = 0.01). Conclusion: Most of the xerostomia-related QOL scores improved in time after radiotherapy without altering the global QOL, which remained high. The recovery of the dry mouth feeling was significantly correlated with the recovery in parotid flow ratio. [ABSTRACT FROM AUTHOR]