BackgroundWhole brain radiotherapy (WBRT) has been the treatment of choice for patients with brain metastases. However, change/decline of neurocognitive functions (NCFs) resulting from impaired hippocampal neurogenesis might occur after WBRT. It is reported that conformal hippocampal sparing would provide the preservation of NCFs. Our study aims to investigate the hippocampal dosimetry and to demonstrate the correlation between hippocampal dosimetry and neurocognitive outcomes in patients receiving hippocampal sparing during WBRT (HS-WBRT).MethodsForty prospectively recruited cancer patients underwent HS-WBRT for therapeutic or prophylactic purposes. Before receiving HS-WBRT, all participants received a battery of baseline neurocognitive assessment, including memory, executive functions and psychomotor speed. The follow-up neurocognitive assessment at 4 months after HS-WBRT was also performed. For the delivery of HS-WBRT, Volumetric Modulated Arc Therapy (VMAT) with two full arcs and two non-coplanar partial arcs was employed. For each treatment planning, dose volume histograms were generated for left hippocampus, right hippocampus, and the composite hippocampal structure respectively. Biologically equivalent doses in 2-Gy fractions (EQD2) assuming an alpha/beta ratio of 2 Gy were computed. To perform analyses addressing the correlation between hippocampal dosimetry and the change in scores of NCFs, pre- and post-HS-WBRT neurocognitive assessments were available in 24 patients in this study.ResultsScores of NCFs were quite stable before and after HS-WBRT in terms of hippocampus-dependent memory. Regarding verbal memory, the corresponding EQD2 values of 0, 10, 50, 80 % irradiating the composite hippocampal structure with <12.60 Gy, <8.81, <7.45 Gy and <5.83 Gy respectively were significantly associated with neurocognitive preservation indicated by the immediate recall of Word List Test of Wechsler Memory Scale-III. According to logistic regression analyses, it was noted that dosimetric parameters specific to left sided hippocampus exerted an influence on immediate recall of verbal memory (adjusted odds ratio, 4.08; p-value, 0.042, predicting patients’ neurocognitive decline after receiving HS-WBRT).ConclusionsFunctional preservation by hippocampal sparing during WBRT is indeed achieved in our study. Providing that modern VMAT techniques can reduce the dose irradiating bilateral hippocampi below dosimetric threshold, patients should be recruited in prospective trials of hippocampal sparing during cranial irradiation to accomplish neurocognitive preservation while maintaining intracranial control.Trial registrationCurrent Controlled Trials NCT02504788Electronic supplementary materialThe online version of this article (doi:10.1186/s13014-015-0562-x) contains supplementary material, which is available to authorized users.

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Study Type – Therapy (case series) Level of Evidence 4 OBJECTIVE To determine the effectiveness of the Resonance ureteral stent and clarify the risk factors that lead to stent failure. In the present study, we review our clinical experiences using Resonance stent in treating malignant and benign ureteral obstruction. PATIENTS AND METHODS Nineteen patients with extrinsic malignant ureteral obstruction (n= 15) and benign stricture (n= 4) were retrospectively evaluated. All patients had received Resonance stent insertion through antegrade or cystoscopic retrograde approaches. The pre‐insertion and follow‐up interventions included image studies and biochemical tests. The insertion success rate, obstruction patency rate and complications were reviewed. For categorical variables, the chi‐square test and Fisher’s exact test were carried out to determine associations between variables. RESULTS The technical success rate of stent insertion was 84.6%. The mean follow‐up was 5 months (range 1–10.5 months). Five stents failed to alleviate the obstruction, and the patency rate was 77.3% (17/22). Patients who had had previous radiation therapy had a lower ureter patency rate in comparison with non‐radiation patients (50% vs 92.3% respectively, P= 0.039). The 6‐ and 9‐month patency rates were 81.0% with 11 stents and 27.0% with 3 stents, respectively. CONCLUSIONS The results of the present study demonstrated that malignant or benign ureteral obstruction could be treated safely and sufficiently with the Resonance metallic stent. Careful patient selection is critical to achieve successful results. For malignant ureteral obstruction, previous radiation therapy is a risk factor for stent failure.