We aimed to restore dose-volume parameters of swallowing-related structures (SRSs) by evaluating long-term swallowing dysfunctions after radiotherapy (RT) in head and neck cancer patients (HNCPs). Materials and Methods: Head and neck cancer patients whose pharyngeal region was involved in RT portal and treated with definitive RT/chemoradiotherapy (CRT) were included in the analyses. Patients underwent objective swallowing assessment by flexible endoscopic evaluation of swallowing (FEES). Volumes of SRSs that received 55 Gy (V 55) (mean dose [D mean ]) were evaluated according to the dose-volume histograms of each patient. For every SRS, optimal dose-volume cutoff values were determined by receiver operating characteristic curve analysis. Results: Fifty-five patients at a median 20 months (range, 12-26 months) after their treatments were evaluated. There was a strong negative correlation between FEES scores and dose-volume parameters of SRS (r ⩽-0.5, P < .0001). According to our results, middle pharyngeal constrictor (MPC) and inferior pharyngeal constrictor (IPC) had a D mean > 57 Gy, base of tongue (BOT) D mean > 50 Gy, supraglottic larynx (SGL) and glottic larynx (GL) D mean > 55 Gy, and cervical esophagus (CE) D mean > 45 Gy. MPC V 55 > 70%, IPC V 55 > 50%, BOT V 55 > 65%, CE V 55 > 40%, and SGL and GL V 55 > 50% were significant predictors for dysphagia. Conclusion: It was found that dysphagia correlates strongly with dose-volume parameters of SRSs. IPC, SGL, and CE were found to be structures significantly associated with dysphagia.

To evaluate the radiation induced adverse effects on ocular structures in head and neck cancer patients and investigate the radiation dose-volume effects on the cornea, lacrimal gland, retina, optic nerve and chiasm. Materials and MethodsA total of 38 eyes of 19 patients were included in this prospective, cohort study. All patients underwent complete ophthalmological examination in addition to contrast sensitivity, visual field and visual evoked potentials (VEP) tests. Ophthalmological examinations and

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Objective:The head and neck squamous cell carcinoma (HNSCC) is the sixth most common type of cancer worldwide and the 5-year survival rate of patients is by 40-50 %. Radiotherapy is one of the important treatments for HNSCC. circRNAs, which are much more stabil than other RNAs because of their circular structure, have the potential to be a biomarker for all types of cancer. Therefore, the alterations of circRNAs expression in HNSCC cells and after irradiation was investigated. Methods: Pharyngeal cancer (Detroit-562) and healthy fibroblast (WI-38) cell lines were used. After appropriate irradiation dose for Detroit-562 cells was determined by colony formation assay, Detroit-562 cells were irradiated with 4 grays. The expression levels of 122 circRNA molecules in all groups were examined by RT-qPCR. The results were evaluated using CircNet and TCGA platforms. Results: In this study, 60 circRNAs were not expressed in any cell line, whereas 62 were found to be expressed in at least one of the groups, including irradiated Detroit-562, Detroit-562, and WI-38 cell lines. Among them, seven circRNAs were detected in all groups and expressed higher in Detroit-562 than two groups. Interestingly, these circRNAs were significantly decreased in irradiated group, exhibiting similar expression levels with healthy group. Bioinformatics analyses showed that the host genes of these circRNAs was also higher expressed in HNSCC tissue. Conclusions: Differential expression of circRNAs in cancers and changes with treatment revealed that they could be potential diagnostic and monitoring biomarkers in cancer. However, further studies need in this regard.

AimThe data used in brachytherapy planning are obtained from homogeneous mediums. In practice, the heterogeneous tissues and materials affect the dose distribution of brachytherapy. It is aimed to investigate the effect of air cavities on brachytherapy dose distribution using a specially designed device.Material and methodsIn this study, the special device designed with different volumes of air and water to be irradiated and measured at different depths using EBT3 Gafchromic films. EBT3 Gafchromic films were preferred for this study because they can be cut to the shape of the experimental geometry, are water resistance and double directional usability.ResultsIn our study, sudden dose increases and decreases were observed at the water–air–water interfaces. Increases were 9, 11·8 and 15% in the 13, 18 and 22 mm apparatus, respectively. These effects were expected and the results were consistent with the literature and within the tolerance limits stated in the clinical dose guidelines. The most important result is that the percent depth–dose curve of the radiation passing through the air to the water and only passing through the water medium is different. The average differences were 1·97, 2·97 and 2·31% for the 13, 18 and 22 mm apparatus, respectively.ConclusionAlthough the effect of heterogeneity may be neglected according to clinical guidelines, it is suggested that the dose effect of heterogeneity is taken into account so that the dose can be estimated sensitively. Brachytherapy plans using dose data without considering air gaps may cause erroneous dose distributions due to heterogeneity of tissue.