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Introduction: Contrast media are frequently used during radiation therapy simulation. However, there are concerns about dosimetric variations when dose calculation is done on contrast-enhanced computed tomography (CT). This study evaluates the dosimetric effect of oral contrast during three-dimensional conformal radiotherapy (3D-CRT) and volumetric modulated arc radiotherapy (VMAT) planning. Methods: Rectal cancer patients were consecutively enrolled. For each patient, one unenhanced CT and one contrast-enhanced CT were taken using oral and intravenous contrast. Then, a 3D-CRT plan and an Intensity-modulated radiation therapy (IMRT)/VMAT plan were generated in the enhanced CT, and the dose distribution was recalculated in the respective unenhanced CT. The beam intensities were kept the same as for the enhanced CT plans. Finally, the unenhanced and enhanced plans were compared by calculating the gamma index. Results: For 3D-CRT plans, there were statistically significant differences in second phase planning target volume (PTV) D2% (Mean difference (MD) between unenhanced and enhanced CT 0·01 Gy, 95% CI [0·003 to 0·02 Gy]) and in maximum doses to the bladder (MD 0·26 Gy, 95% CI [0·05 to 0·47 Gy]). For IMRT/VMAT plans, there were statistically significant differences in small intestine V45 Gy (MD 3·1 cc, 95% CI [0·81 to 5·4 cc]), bladder V45 Gy (MD 2·9%, 95% CI [1·4 to 4·3%]) and maximum dose to the bladder (MD 0·65 Gy, 95% CI [0·46 Gy to 0·85 Gy]). In addition, for PTV D98% the MD between unenhanced and enhanced CT was 0·22 Gy 95% CI [0·05 to 0·39]. Conclusions: For most of the dose metrics, the differences were not clinically meaningful. The greatest differences were found in VMAT plans, especially in V45 Gy of the small intestine. This difference could lead to an underestimation of dose–volume metrics when the plan is based on an enhanced CT. The use of small bowel oral contrast does not significantly influence dose calculations and may not affect the acceptability of plans when adhering to constraints.

Background Although cannabis and cannabinoids are widely used with therapeutic purposes, their claimed efficacy is highly controversial. For this reason, medical cannabis use is a broad field of research that is rapidly expanding. Our objectives are to identify, characterize, appraise, and organize the current available evidence surrounding therapeutic use of cannabis and cannabinoids, using evidence maps. Methods We searched PubMed, EMBASE, The Cochrane Library and CINAHL, to identify systematic reviews (SRs) published from their inception up to December 2017. Two authors assessed eligibility and extracted data independently. We assessed methodological quality of the included SRs using the AMSTAR tool. To illustrate the extent of use of medical cannabis, we organized the results according to identified PICO questions using bubble plots corresponding to different clinical scenarios. Results A total of 44 SRs published between 2001 and 2017 were included in this evidence mapping with data from 158 individual studies. We extracted 96 PICO questions in the following medical conditions: multiple sclerosis, movement disorders (e.g. Tourette Syndrome, Parkinson Disease), psychiatry conditions, Alzheimer disease, epilepsy, acute and chronic pain, cancer, neuropathic pain, symptoms related to cancer (e.g. emesis and anorexia related with chemotherapy), rheumatic disorders, HIV-related symptoms, glaucoma, and COPD. The evidence about these conditions is heterogeneous regarding the conclusions and the quality of the individual primary studies. The quality of the SRs was moderate to high according to AMSTAR scores. Conclusions Evidence on medical uses of cannabis is broad. However, due to methodological limitations, conclusions were weak in most of the assessed comparisons. Evidence mapping methodology is useful to perform an overview of available research, since it is possible to systematically describe the extent and distribution of evidence, and to organize scattered data.

To generate recommendations on the management of radiotherapeutic treatments during the pandemic, adapted to a country with limited health resources.We did a rapid review of the literature, searching for papers that describe any measures to reduce the risk of COVID-19 infection, as well as management guidelines to reduce the workload, in radiotherapy units. The following conditions were included in the scope of this review: gynecological tumors, breast cancer, gastrointestinal tumors, genitourinary tumors, head and neck tumors, skin cancer, tumors of the central nervous system, and lymphomas. An expert group discussed online the extracted data and drafted the recommendations. Using a modified Delphi method, the consensus was reached among 14 certificated radio-oncologists. The quality of the evidence that supported the recommendations on treatment schedules was assessed.A total of 57 documents were included. Of these, 25 provided strategies to reduce the risk of infection. Recommendations for each condiction were extracted from the remaining documents. The recommendations aim to establish specific parameters where treatments can be omitted, deferred, prioritized, and shortened. Treatment schemes are recommended for each condition, prioritizing hypo-fractionated schemes whenever possible.We propose strategies for the management of radiotherapy services to guarantee the continuity of high-quality treatments despite the health crisis caused by COVID-19.Establecer recomendaciones para la toma de decisiones de manejo en radioterapia durante la pandemia de COVID-19, adaptadas a un país con recursos de salud limitados.A través de una revisión rápida de la literatura se buscaron publicaciones que describieran medidas para reducir el riesgo de infección por COVID-19, así como también pautas de manejo para reducir la carga de trabajo en las unidades de radioterapia. Se incluyeron en el alcance de esta revisión las siguientes patologías: tumores ginecológicos, cáncer de mama, tumores gastrointestinales, tumores genitourinarios, tumores de cabeza y cuello, cáncer de piel, tumores del sistema nervioso central y linfomas. Un grupo de expertos discutió en línea los datos extraídos y redactó las recomendaciones. Mediante un método Delphi modificado, se evaluó el consenso entre 14 radio-oncólogos certificados. Se evaluó la calidad de la evidencia que sustentó las recomendaciones sobre esquemas de tratamiento.Se incluyeron un total de 57 documentos. De 25 trabajos se extrajeron las estrategias para reducir el riesgo de infección. De los restantes, se obtuvieron las recomendaciones para cada patología. Las recomendaciones están orientadas a establecer escenarios específicos donde se pueden omitir, diferir, priorizar y acortar los tratamientos. En el ítem de acortar se recomiendan esquemas de tratamiento para cada patología, priorizando los esquemas hipofraccionados cuando fue posible.Se plantean estrategias para la gestión de los servicios de radioterapia con el objetivo de garantizar que los tratamientos de alta calidad para pacientes oncológicos sigan entregándose, pese a la crisis sanitaria ocasionada por COVID-19.

Background Red blood cell (RBC) transfusions are essential in health care. The quality of recommendations included in clinical practice guidelines (CPG), regarding this intervention, has not been systematically evaluated. This paper systematically assessed CPGs for RBC‐transfusion, to appraise their methodological quality, to explore changes in quality over time, and to assess the consistency of the hemoglobin threshold (HT) recommendations. Methods We searched for CPGs that included recommendations of RBC‐transfusion in generic databases, compiler entities, registries, clearinghouses and guideline developers. Three reviewers extracted data on CPGs characteristics and HT recommendations, independently appraised the quality of the studies using AGREE II and resolved disagreements by consensus. Results We examined 16 CPGs. Mean scores (mean ± SD) were: scope and purpose (59.4% ± 19.8%), stakeholder involvement (43.2% ± 22.6%), rigor of development (50% ± 25%), clarity of presentation (74.4% ± 12.6%), applicability (19.4% ± 18.8%), and editorial independence (41% ± 30%). Seven CPGs recommended a restrictive strategy for RBC transfusion; four CPGs gave a guarded statement considering an HT of 7 g/dL, as safe to prescribe an RBC transfusion. Eight CPGs did not provide an HT stating that RBC transfusions should not be prescribed by HT alone. Conclusions Only 3 out of the 16 evaluated CPGs were “recommended” by the independent evaluators. Four domains “stakeholder involvement,” “rigor of development,” applicability,” and “editorial independence” had serious shortcomings. Recommendations about the use of an HT for RBC‐transfusion were heterogeneous among guidelines. Greater efforts are needed to provide high‐quality CPGs in the RBC‐transfusion practice.

This study was aimed to describe the gastric cancer mortality trend, and to analyze the spatial distribution of gastric cancer mortality in Ecuador, between 2004 and 2015.Data were collected from the National Institute of Statistics and Census (INEC) database. Crude gastric cancer mortality rates, standardized mortality ratios (SMRs) and indirect standardized mortality rates (ISMRs) were calculated per 100,000 persons. For time trend analysis, joinpoint regression was used. The annual percentage rate change (APC) and the average annual percent change (AAPC) was computed for each province. Spatial age-adjusted analysis was used to detect high risk clusters of gastric cancer mortality, from 2010 to 2015, using Kulldorff spatial scan statistics.In Ecuador, between 2004 and 2015, gastric cancer caused a total of 19,115 deaths: 10,679 in men and 8436 in women. When crude rates were analyzed, a significant decline was detected (AAPC: -1.8%; p0.001). ISMR also decreased, but this change was not statistically significant (APC: -0.53%; p=0.36). From 2004 to 2007 and from 2008 to 2011 the province with the highest ISMR was Carchi; and, from 2012 to 2015, was Cotopaxi. The most likely high occurrence cluster included Bolívar, Los Ríos, Chimborazo, Tungurahua, and Cotopaxi provinces, with a relative risk of 1.34 (p0.001).There is a substantial geographic variation in gastric cancer mortality rates among Ecuadorian provinces. The spatial analysis indicates the presence of high occurrence clusters throughout the Andes Mountains.

Background The constant search for an improved esthetic dental material has led investigators to realize that its performance depends on the conditions where the material is used. It has been probed that the contact with mouth rinses triggers alterations, reason why the aim of this study was to identify their possible effects of it on the integrity of nanohybrid composite resin and resin modified glass ionomer. Material and methods A total of 144 samples were manufactured with two nanohybrid composite resins and two resin modified glass ionomer restorative materials. The specimens were immersed in one of the three mouthwashes used in the study, for a total of 1092 minutes, with intervals of contact with artificial saliva. This strategy simulates three years of constant use of mouthwashes. The samples weight and surface roughness measurement was recorded with a precision scale and profilometer, at different stages: At the beginning of the study, after 546 minutes (simulating one and a half year), and after 1092 minutes (simulating three years). Results The collected data on surface roughness and weight were submitted to the analysis of variance (ANOVA), with repeated measures of three factors. The results determined shifts in values in terms of weight and roughness in all the samples. The composite resin "Grandio" group was the one that showed bigger shifts, while the glass ionomer group "Vitremer" showed stability on its structure. The evaluated mouthwashes displayed similar behavior between each other. Conclusions The use of mouthwashes triggered changes on the structure of both dental materials: composite resin and resin modified glass ionomer mostly associated with surface roughness. Key words:Glass ionomer, composite resin, mouthwash, roughness, degradation.