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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.

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Introduction To evaluate the clinical and dosimetric parameters that increase the risk of radiation pneumonitis (RP) in locally advanced non‐small cell lung cancer (NSCLC) patients treated with concomitant chemoradiotherapy of nationwide multicentric data analysis. Methods All data of 268 patients who underwent definitive chemoradiotherapy were retrospectively collected from eight institutes participating in this study. Patient, tumor and treatment‐related factors and dosimetric parameters were analyzed for grade ≥2 RP. The toxicity scoring system of The Radiation Therapy Oncology Group used for grading the severity of pneumonitis. A relationship with the risk of RP with potential predictive factors were evaluated by univariate and multivariate analyses. A recursive partition analysis (RPA) was applied to stratify patients according to the risk of developing RP. Results There were 90 (33.6%) patients who had grade ≥2 RP. The median time to pneumonitis after treatment was 4 months (range:1‐6 months). In univariate analysis, diabetes mellitus (DM), use of cisplatin/etoposide, total and daily radiotherapy (RT) fraction dose, the planning target volume (PTV) size, mean lung dose, V5, V10 and RT technique were associated with the development of pneumonitis. In multivariate analysis, only DM (P = 0.008) was found to be independent risk factors for RP. According to RPA, the risk of developing RP was highest in patients with DM. Conclusions In our study, besides the known dosimetric factors, DM was found to be the most important risk factor causing RP development in multivariate analysis and RPA. The risk is tripled compared to patients without DM.

Objectives:Hippocampal avoidance during whole-brain radiotherapy is performed to prevent neural stem cell injury causing neurocognitive dysfunction. Nevertheless, the estimated risk of metastases in hippocampal avoidance area in small-cell lung cancer is unknown. The current study aimed to characterize the metastatic distribution within the brain relative to the hippocampus, estimate the incidence of hippocampal metastasis in patients with small-cell lung cancer, and identify clinical and radiographic variables that may be associated with the risk of hippocampal avoidance area metastasis.Materials and Methods:Patients with small-cell lung cancer treated with therapeutic whole-brain radiotherapy between January 2010 and December 2015 were reviewed. T1-weighted, postcontrast axial magnetic resonance images obtained just before therapeutic cranial irradiation were retrieved and reviewed for each patient. The hippocampal avoidance area was defined as hippocampus and 5-mm ring area adjacent to the hippocampus to account for necessary dose falloff between the hippocampus and the whole-brain planning target volume. Metastatic lesions within hippocampal avoidance area were defined as hippocampal metastasis. Hippocampal metastasis rate and characteristics of patients with hippocampal metastasis were analyzed and compared to patients without hippocampal metastasis.Results:Fifty-four patients evaluated with cranial magnetic resonance imaging were enrolled. Hippocampal metastasis rate was 32% (17 patients). A total of 4.4% of all metastases involved the hippocampal avoidance area. The most common location was frontal lobe. Being younger than 65 years of age was found to be an independent risk factor for HM (odds ratio: 4.8, 95% confidence interval: 1-23.2, P = .049). The number of brain metastases was significantly higher in patients with hippocampal metastasis (P = .027), and hippocampal metastasis rate was also higher in patients having larger hippocampus (P = .026) and larger brain volumes (P = .02).Conclusion:Hippocampal metastasis might be more common in small-cell lung cancer. Reducing the dose to the hippocampus by hippocampal avoiding whole-brain radiotherapy plan in small-cell lung cancer may be risky for the development of HM compared with other malignant solid tumors.