Personalized treatment planning in eye brachytherapy for ocular melanoma: Dosimetric analysis on ophthalmic structure at risk

Purpose: To evaluate the impact on dose distribution to eye organs-at-risk (eOARs) of a computed tomography (CT)-based treatment planning in eye plaque brachytherapy (EPB) treatment. Methods: We analyzed 19 ocular melanoma patients treated with ruthenium-106 plaques to a total dose of 100 Gy to tumor apex using conventional central-axis-point dose calculation. Treatments were re-planned using the Plaque Simulator (PS) software implementing two different strategies: a personalized CT-eye-model (CT-PS) and a standard-eye-model (SEM-PS) defined by Collaborative Ocular Melanoma Study. Dice coefficient and Hausdorff distance evaluated the concordance between eye-bulb-models. Mean doses (Dmean) to tumor and eOARs were extracted from Dose-Volume-Histograms and Retinal-Dose-Area-Histogram. Differences between planning approaches were tested by Wilcoxon signed-rank test. Results: In the analyzed cohort, 8 patients (42%) had posterior tumor location, 8 (42%) anterior, and 3 (16%) equatorial. The SEM did not accurately described the real CT eye-bulb geometry (median Hausdorff distance 0.8 mm, range: (0.4–1.3) mm). Significant differences in fovea and macula Dmean values were found (p = 0.04) between CT-PS and SEM-PS schemes. No significant dosimetric differences were found for tumor and other eOARs. The planning scheme particularly affects the OARs closest to the tumor with a general tendency of SEM-PS to overestimate the doses to the OARs closest to the tumor. Conclusion: The dosimetric accuracy achievable with CT-PS EPB treatment planning may help to identify ocular melanoma patients who could benefit the most from a personalized eye dosimetry for an optimal outcome in terms of tumor coverage and eOARs sparing. Further research and larger studies are underway

The organ equivalent dose to quantify secondary cancer induction in breast after VMAT treatments

Introduction: During volumetric arc therapy (VMAT) therapy, the dose delivered involves significant area and organs with low dose. In order to study the Radiation Therapy (RT) cancer induction probability, the risk for contralateral breast and lung secondary tumor was evaluated, estimating the organ equivalent dose (OED). Materials and Methods: The dose distribution of 30 breast cancer patients treated with VMAT techniques were analyzed in this retrospective study. The cohort was divided for treatment side (right/left) and the OED for each organ was calculated from the dose volume histogram (DVH). The bell shaped model formula was applied in a MATLAB® toolbox to estimate secondary cancer induction in breast and lung tissues. Contralateral and ipsilateral statistic outcomes were assessed using SPSS®. Results: A mean ODE of 2.09 ± 0.32, 1.94 ± 0.32 and 2.55 ± 0.61 was obtained for contralateral lung, ipsilateral lung and contralateral breast respectively. For contralateral organs, an ANOVA analysis (sign. > 0.30) confirmed that these results were independent to the side of treatment, with an intra-group variability of [2.1 ÷ 3.1 Gy] and [2.2 ÷ 3.8 Gy] for the right and left side. For ipsilateral organs, in agreement with other scientific works in literature, the OED showed a less variability (±0.16 Gy). Conclusions: The ODE value is a simple and useful estimation of radiation secondary cancer induction of VMAT treatments based on a DVH analysis. With a cross correlation between contralateral and ipsilateral structures, an independence from the side of treatment was detected, highlighting a lower intra-organ variability in case of ipsilateral comparison. To increase the robustness of the study, the bell shaped model used could be related to the time patterns of cancer induction. Moreover, absolute risk should be investigated in a larger patients' cohort or in national data mining

Variation in palliative care of esophageal cancer in clinical practice: factors associated with treatment decisions

Various treatments are available for the palliation of esophageal cancer, but the optimal therapeutic approach is unclear. This study aimed to assess the palliative treatment modalities used in patients with inoperable esophageal cancer and to identify factors associated with treatment decisions. A population-based, retrospective cohort study was conducted using data from the nationwide Netherlands Cancer Registry and medical records of seven participating hospitals. Patients diagnosed with stage III-IV inoperable esophageal or gastric cardia cancer in the central part of the Netherlands between 2001 and 2010 were included. Logistic regression analyses were performed to identify determinants of treatment choices. In total, 736 patients were initially treated with best supportive care (21%), stent placement (19%), chemotherapy (18%), external beam radiotherapy (EBRT) (16%), brachytherapy (6%), a combination of EBRT and brachytherapy (6%), a combination of chemotherapy and EBRT (5%) or another treatment (9%). The palliative approach varied for disease stage (P  < 0.01) and hospital of diagnosis (P  < 0.01). Independent factors affecting treatment decisions were age, degree of dysphagia, tumor histology, tumor localization, disease stage, and hospital of diagnosis. For example, patients diagnosed in one hospital were less likely to be treated with EBRT than with stent placement compared to patients in another hospital (odds ratio 0.20, 95% confidence interval 0.07-0.59). In conclusion, the initial palliative approach of patients with inoperable esophageal cancer varies widely and is not only associated with patient- and disease-related factors, but also with hospital of diagnosis. These findings suggest a lack of therapeutic guidance and highlight the need for more evidence on palliative care strategies for esophageal cance