Spatially fractionated radiation therapy: a critical review on current status of clinical and preclinical studies and knowledge gaps

Spatially fractionated radiation therapy (SFRT) is a therapeutic approach with the potential to disrupt the classical paradigms of conventional radiation therapy. The high spatial dose modulation in SFRT activates distinct radiobiological mechanisms which lead to a remarkable increase in normal tissue tolerances. Several decades of clinical use and numerous preclinical experiments suggest that SFRT has the potential to increase the therapeutic index, especially in bulky and radioresistant tumors. To unleash the full potential of SFRT a deeper understanding of the underlying biology and its relationship with the complex dosimetry of SFRT is needed. This review provides a critical analysis of the field, discussing not only the main clinical and preclinical findings but also analyzing the main knowledge gaps in a holistic way.

TOPAS simulation of photoneutrons in radiotherapy: accuracy and speed with variance reduction

We provide optimal particle split numbers for speeding up TOPAS Monte Carlo simulations of linear accelerator (linac) treatment heads while maintaining accuracy. In addition, we provide a new TOPAS physics module for simulating photoneutron production and transport. TOPAS simulation of a Siemens Oncor linac was used to determine the optimal number of splits for directional bremsstrahlung splitting as a function of the field size for 6MV and 18MV x-ray beams. The linac simulation was validated against published data of lateral dose profiles and percentage depth-dose curves (PDD) for the largest square field (40cm side). In separate simulations, neutron particle split and the custom TOPAS physics module was used to generate and transport photoneutrons, called "TsPhotoNeutron". Verification of accuracy was performed by comparing simulations with published measurements of: 1) neutron yields as a function of beam energy for thick targets of Al, Cu, Ta, W, Pb and concrete; and 2) photoneutron energy spectrum at 40cm laterally from the isocenter of the linac from an 18MV beam with closed jaws and MLC. The optimal number of splits obtained for directional bremsstrahlung splitting enhanced the computational efficiency by two orders of magnitude. The efficiency decreased with increasing beam energy and field size. Calculated lateral profiles in the central region agreed within 1mm/2% from measured data, PDD curves within 1 mm/1%. For the TOPAS physics module, at a split number of 146, the efficiency of computing photoneutron yields was enhanced by a 27.6 factor, whereas it improved the accuracy over existing Geant4 physics modules. This work provides simulation parameters and a new TOPAS physics module to improve the efficiency and accuracy of TOPAS simulations that involve photonuclear processes occurring in high-Z materials found in linac components, patient devices, and treatment rooms, as well as to explore new therapeutic modalities such as very-high-energy electron therapy.

Thoracic Proton Minibeam Radiation Therapy: Tissue Preservation and Survival Advantage over Conventional Proton Therapy

PURPOSE

Proton Minibeam Radiotherapy (pMBRT) is an innovative radiation therapy approach that highly modulates the spatial dimension of the dose delivery using narrow, parallel, and submillimetric proton beamlets. pMBRT has proven its remarkable healthy tissue preservation in the brain and skin. This study assesses the potential advantages of pMBRT for thoracic irradiations compared to conventional radiotherapy in terms of normal tissue toxicity. The challenge here was the influence of respiratory motion on the typical peak and valley dose patterns of pMBRT and its potential biological impact.

METHODS AND MATERIALS

the whole thorax of naïve C57BL/6 mice received one fraction of high dose (18 Gy) pMBRT or conventional proton therapy (CPT) without any respiratory control. The development of radiation-induced pulmonary fibrosis was longitudinally monitored using cone-beam computed tomography. Anatomopathological analysis was carried out at 9 months post-irradiation and focused on the reaction of the lungs' parenchyma and the response of cell types involved in the development of radiation-induced fibrosis and lung regeneration as Alveolar Type II (AT2) epithelial cells, club cells, and macrophages.

RESULTS

pMBRT has milder effects on survival, skin reactions, and lung fibrosis compared to CPT. The pMBRT-induced lung changes were more regional and less severe, with evidence of potential reactive proliferation of AT2 epithelial cells and less extensive depletion of club cells and macrophage invasion than the more damaging effects observed in CPT.

CONCLUSION

pMBRT appears suitable to treat moving targets, holding a significant ability to preserve healthy lung tissue, even without respiratory control or precise targeting.

Creating uniform cluster dose spread-out Bragg peaks for proton and carbon beams

BACKGROUND

Preliminary data have shown a close association of the generalized ionization cluster size dose (in short, cluster dose) with cell survival, independent of particle type, and energy, when cluster dose is derived from an ionization detail parameter preferred for its association with cell survival. Such results suggest cluster dose has the potential to replace RBE-weighted dose in proton and ion beam radiotherapy treatment plan optimization, should a uniform cluster dose lead to comparable biological effects. However, further preclinical investigations are warranted to confirm this premise.

PURPOSE

To present an analytical approach to create uniform cluster dose spread-out Bragg peaks (SOBP) for evaluation of the potential of cluster dose to result in uniform biological effect.

METHODS

We modified the coefficients of the Bortfeld and Schlegel weight formula, an analytical method typically used for the creation of radiation dose SOBP in particle therapy, to produce uniform cluster dose SOBP of different widths (1-5 cm) at relevant clinical proton and carbon beam energies. Optimum parameters were found by minimization of the ratio between the maximum and minimum cluster dose in the SOBP region using the Nelder-Mead method.

RESULTS

The coefficients of the Bortfeld and Schlegel weight formula leading to uniform cluster dose SOBPs were determined for each combination of beam energy and SOBP width studied. The uniformity of the resulting cluster dose SOBPs, calculated as the relative difference between the maximum and minimum cluster dose within the SOBP, was within 0.3%-3.5% for the evaluated proton beams and 1.3%-3.4% for the evaluated carbon beams.

CONCLUSIONS

The modifications to the analytical approach to create radiation dose SOBPs resulted in uniform cluster dose proton and carbon SOBPs over a wide range of beam energies and SOBP widths. Such SOBPs should prove valuable in preclinical investigations for the selection of nanodosimetric quantities to be used in proton and ion therapy treatment planning.

Ionization detail parameters and cluster dose: a mathematical model for selection of nanodosimetric quantities for use in treatment planning in charged particle radiotherapy

Objective. To propose a mathematical model for applying ionization detail (ID), the detailed spatial distribution of ionization along a particle track, to proton and ion beam radiotherapy treatment planning (RTP).Approach. Our model provides for selection of preferred ID parameters (Ip) for RTP, that associate closest to biological effects. Cluster dose is proposed to bridge the large gap between nanoscopicIpand macroscopic RTP. Selection ofIpis demonstrated using published cell survival measurements for protons through argon, comparing results for nineteenIp:Nk,k= 2, 3, …, 10, the number of ionizations in clusters ofkor more per particle, andFk,k= 1, 2, …, 10, the number of clusters ofkor more per particle. We then describe application of the model to ID-based RTP and propose a path to clinical translation.Main results. The preferredIpwereN4andF5for aerobic cells,N5andF7for hypoxic cells. Significant differences were found in cell survival for beams having the same LET or the preferredNk. Conversely, there was no significant difference forF5for aerobic cells andF7for hypoxic cells, regardless of ion beam atomic number or energy. Further, cells irradiated with the same cluster dose for theseIphad the same cell survival. Based on these preliminary results and other compelling results in nanodosimetry, it is reasonable to assert thatIpexist that are more closely associated with biological effects than current LET-based approaches and microdosimetric RBE-based models used in particle RTP. However, more biological variables such as cell line and cycle phase, as well as ion beam pulse structure and rate still need investigation.Significance. Our model provides a practical means to select preferredIpfrom radiobiological data, and to convertIpto the macroscopic cluster dose for particle RTP.

Analysis of the impact of green urban areas in historic fortified cities using Landsat historical series and Normalized Difference Indices

Urban green areas minimize the negative effects of climatic change and improve the sustainability of historic cities. Despite this, green areas have traditionally been considered a threat to heritage buildings because they cause humidity changes, that accelerate degradation processes. Within this context, this study evaluates the trends in the inclusion of green areas in historic cities and the effects it causes on humidity and conservation of earthen fortifications. To achieve this goal, vegetative and humidity information has been obtained since 1985 from Landsat satellite images. The historical series of images has been statistically analysed in Google Earth Engine to obtain maps that show the means, 25th, and 75th percentiles of the variations registered in the last 35 years. The results allow visualizing spatial patterns and plotting the seasonal and monthly variations. In the decision-making process, the proposed method allows to monitor whether the presence of vegetation is an environmental degradation agent in the nearby earthen fortifications.The analysis of the historic fortified cities of Seville and Niebla (Spain) shows a gradual increase in green areas and an interest in locating them near the earthen fortifications. The impact on the fortifications is specific to each type of vegetation and can be positive or negative. In general, the low humidity registered indicates low danger, and the presence of green areas favours drying after heavy rains. This study suggests that increasing green spaces to historic cities does not necessarily endanger the preservation of earthen fortifications. Instead, managing both heritage sites and urban green areas together can encourage outdoor cultural activities, reduce the impacts of climate change, and enhance the sustainability of historic cities.

Climate change, large fires, and cultural landscapes in the mediterranean basin: An analysis in southern Spain

Understanding the factors that influence fire regimes in Mediterranean climates is essential to reduce their risk. This research uses Climate Hazards Group InfraRed Precipitation with Station (CHIRPS) and Moderate-Resolution Imaging Spectroradiometer (MODIS) satellite resources to evaluate recent changes in land surface temperature, precipitation, and vegetation and their effects in the occurrence of large fires in the Mediterranean Basin. The results of the analysis of 335 fire events occurred in southern Spain from 2001 to 2020 show an increase in hazardous meteorological factors linked to droughts and thermal anomalies. The study also examines the potential of preserving traditional landscapes to minimize such risk. In fact, the maintenance and recovering of traditional agro-pastoral activities is an effective option to reduce flammability and increase the resilience of cultural landscapes in hazardous climatic conditions.

Proton Beam Therapy in the Oligometastatic/Oligorecurrent Setting: Is There a Role? A Literature Review

BACKGROUND

Stereotactic ablative radiotherapy (SABR) and stereotactic radiosurgery (SRS) with conventional photon radiotherapy (XRT) are well-established treatment options for selected patients with oligometastatic/oligorecurrent disease. The use of PBT for SABR-SRS is attractive given the property of a lack of exit dose. The aim of this review is to evaluate the role and current utilisation of PBT in the oligometastatic/oligorecurrent setting.

METHODS

Using Medline and Embase, a comprehensive literature review was conducted following the PICO (Patients, Intervention, Comparison, and Outcomes) criteria, which returned 83 records. After screening, 16 records were deemed to be relevant and included in the review.

RESULTS

Six of the sixteen records analysed originated in Japan, six in the USA, and four in Europe. The focus was oligometastatic disease in 12, oligorecurrence in 3, and both in 1. Most of the studies analysed (12/16) were retrospective cohorts or case reports, two were phase II clinical trials, one was a literature review, and one study discussed the pros and cons of PBT in these settings. The studies presented in this review included a total of 925 patients. The metastatic sites analysed in these articles were the liver (4/16), lungs (3/16), thoracic lymph nodes (2/16), bone (2/16), brain (1/16), pelvis (1/16), and various sites in 2/16.

CONCLUSIONS

PBT could represent an option for the treatment of oligometastatic/oligorecurrent disease in patients with a low metastatic burden. Nevertheless, due to its limited availability, PBT has traditionally been funded for selected tumour indications that are defined as curable. The availability of new systemic therapies has widened this definition. This, together with the exponential growth of PBT capacity worldwide, will potentially redefine its commissioning to include selected patients with oligometastatic/oligorecurrent disease. To date, PBT has been used with encouraging results for the treatment of liver metastases. However, PBT could be an option in those cases in which the reduced radiation exposure to normal tissues leads to a clinically significant reduction in treatment-related toxicities.

Endourological treatment of ectopic ureterocele. Our experience in the last 15 years

OBJECTIVE

To assess the efficacy of the endourological treatment of ectopic ureterocele in children in a large series and with a long-term follow-up.

MATERIALS AND METHODS

A retrospective, descriptive study of patients with ectopic ureterocele who had undergone surgery in our institution in the last 15 years was carried out. All patients were treated using an endourological approach, both for ureterocele and postoperative vesicoureteral reflux (VUR).

RESULTS

40 patients were treated -55% with left involvement and 5% with bilateral involvement. Mean age at diagnosis was 4.97 months, with diagnosis being established prenatally in 54.1% of cases. In all patients but one, endourological puncture of the ureterocele was conducted. Mean age at surgery was 6.96 months (0-1.11). Surgery was performed on an outpatient basis in 94.9% of patients. No perioperative complications were recorded. In the last 30 patients, preoperative voiding cystourethrography was not carried out. 72.5% of patients had postoperative VUR (44.8% into the upper pyelon, 10.3% into the lower pyelon, 17.2% into both, 6.9% into the contralateral system, and 20.7% into the bilateral system), but it was resolved with a single endoscopic procedure in 48.1% of cases (65% of patients were healed with two procedures). VUR was not endoscopically resolved in 3 patients who required ureteral re-implantation. 6 patients required heminephrectomy (n=3) or nephrectomy (n=3) as a result of functional impairment and infections.

CONCLUSION

The endourological treatment of ectopic ureterocele is a little aggressive and little invasive technique that allows the obstruction to be resolved on an outpatient basis, which means bladder surgery -if required- can be performed outside the neonatal period.

Evaluation of the Role of the Immune System Response After Minibeam Radiation Therapy

PURPOSE

Minibeam radiation therapy (MBRT) is an innovative technique that uses a spatial dose modulation. The dose distribution consists of high doses (peaks) in the path of the minibeam and low doses (valleys). The underlying biological mechanism associated with MBRT efficacy remains currently unclear and thus we investigated the potential role of the immune system after treatment with MBRT.

METHODS AND MATERIALS

Rats bearing an orthotopic glioblastoma cell line were treated with 1 fraction of high dose conventional radiation therapy (30 Gy) or 1 fraction of the same mean dose in MBRT. Both immunocompetent (F344) and immunodeficient (Nude) rats were analyzed in survival studies. Systemic and intratumoral immune cell population changes were studied with flow cytometry and immunohistochemistry (IHC) 2 and 7 days after the irradiation.

RESULTS

The absence of response of Nude rats after MBRT suggested that T cells were key in the mode of action of MBRT. An inflammatory phenotype was observed in the blood 1 week after irradiation compared with conventional irradiation. Tumor immune cell analysis by flow cytometry showed a substantial infiltration of lymphocytes, specifically of CD8 T cells and B cells in both conventional and MBRT-treated animals. IHC revealed that MBRT induced a faster recruitment of CD8 and CD4 T cells. Animals that were cured by radiation therapy did not suffer tumor growth after reimplantation of tumoral cells, proving the long-term immunity response generated after a high dose of radiation.

CONCLUSIONS

Our findings show that MBRT can elicit a robust antitumor immune response in glioblastoma while avoiding the high toxicity of a high dose of conventional radiation therapy.

Proton minibeam radiation therapy for treating metastases: A treatment plan study

BACKGROUND

Proton minibeam radiation therapy (pMBRT) is a new radiotherapy approach that has shown a significant increase in the therapeutic window in glioma-bearing rats compared to conventional proton therapy. Such preclinical results encourage the preparation of clinical trials.

PURPOSE

In this study, the potential of pMBRT for treating clinical indications candidates for the first clinical trials (i.e., brain, lung, and liver metastases) was evaluated.

METHODS

Four clinical cases, initially treated with stereotactic radiotherapy (SRT), were selected for this study. pMBRT, SRT, and conventional proton therapy (PT) dose distributions were compared by using three main criteria: (i) the tumor coverage, (ii) the mean dose to organs-at-risk, and (iii) the possible adverse effects in normal tissues by considering valley doses as the responsible for tissue sparing. pMBRT plans consisted of one fraction and one-two fields. Dose calculations were computed by means of Monte Carlo simulations.

RESULTS

pMBRT treatments provide a similar or superior target coverage than SRT, even using fewer fields. pMBRT also significantly reduces the biologically effective dose (BED) to organs-at-risk. In addition, valley and mean doses to normal tissues remain below tolerance limits when treatments are delivered in a single fraction, contrary to PT treatments.

CONCLUSIONS

This work provides a first insight into the possibility of treating metastases with pMBRT. More favorable dose distributions and treatment delivery regimes may be expected from this new approach than SRT. The advantages of pMBRT would need to be confirmed by means of Phase I clinical trials.

Cancer care for Ukrainian refugees: Strategic impact assessments in the early days of the conflict

BACKGROUND

The invasion of Ukraine by Russia in February 2022 has resulted in destruction of healthcare infrastructure and triggered the largest wave of internally displaced populations and refugees since World War Two. Conflicts in transitioned countries such as Ukraine create new non-communicable disease (NCD) challenges, especially for cancer care for refugees and humanitarian assistance in host countries. In the early days, rapid attempts were made to model possible impacts.

METHODS

By evaluating open source intelligence used in the first three months of the conflict through snowball search methods, we aimed to address: (i) burden of cancer in Ukrainian population, specifically considering translating to the refugees population, and its cancer care capacity; ii) baseline capacity/strengths of cancer systems in initial host countries. Moreover, using a baseline scenario based on crude cancer incidence in Ukraine, and considering data from UNHCR, we estimated how cancer cases would be distributed across host countries. Finally, a surveillance assessment instrument was created, intersecting health system's capacity and influx of internally displaced populations and refugees.

FINDINGS AND CONCLUSIONS

The total new cancer patients per month in pre-conflict Ukraine was estimated as 13,106, of which < 1 % are paediatric cases. The estimated cancer cases in the refugee population (combining prevalent and incident), assuming 7.5 million refugees by July 2022 and a female:male ratio of 9:1, was 33,121 individuals (Poland: 19284; Hungary: 3484; Moldova: 2651; Slovakia: 2421; Romania: 5281). According to our assessments, Poland is the only neighbouring country classified as green/yellow for cancer capacity, i.e. sufficient ablility to absorb additional burden into national health system; Slovakia we graded as yellow, Hungary and Romania as yellow/red and Moldova as red.

Buried penis secondary to ectopic scrotum

INTRODUCTION

Ectopic scrotum is a rare clinical entity, potentially associated with other congenital abnormalities. We present the case of a patient with buried penis secondary to ectopic scrotum. The surgical technique was described, and a literature review was carried out.

CLINICAL CASE

1-year-old patient with ectopic right hemiscrotum and the testes within the scrotal sac. A double Z-plasty was performed with two flaps - one above the penis, surrounding the ectopic scrotum, and the other one at the scrotum to modify the bifid scrotum. The upper flap was rotated downwards, which allowed ectopy to be repaired, and the lower flap was used to repair bifidity. No postoperative complications were recorded. Follow-time was 6 months, with good final cosmetic results.

DISCUSSION

Ectopic scrotum is an infrequent congenital malformation. Cutaneous rotation flaps with Z-plasties are a valid treatment option, with good long-term cosmetic results.

Benefit with preventive noninvasive ventilation in subgroups of patients at high-risk for reintubation: a post hoc analysis

Background

High-flow nasal cannula (HFNC) was shown to be non-inferior to noninvasive ventilation (NIV) for preventing reintubation in a general population of high-risk patients. However, some subgroups of high-risk patients might benefit more from NIV. We aimed to determine whether the presence of many risk factors or overweight (body mass index (BMI) ≥ 25 kg/m2) patients could have different response to any preventive therapy, NIV or HFNC in terms of reduced reintubation rate.

Methods

Not pre-specified post hoc analysis of a multicentre, randomized, controlled, non-inferiority trial comparing NFNC and NIV to prevent reintubation in patients at risk for reintubation. The original study included patients with at least 1 risk factor for reintubation.

Results

Among 604 included in the original study, 148 had a BMI ≥ 25 kg/m2. When adjusting for potential covariates, patients with ≥ 4 risk factors (208 patients) presented a higher risk for reintubation (OR 3.4 [95%CI 2.16–5.35]). Patients with ≥ 4 risk factors presented lower reintubation rates when treated with preventive NIV (23.9% vs 45.7%; P = 0.001). The multivariate analysis of overweight patients, adjusted for covariates, did not present a higher risk for reintubation (OR 1.37 [95%CI 0.82–2.29]). However, those overweight patients presented an increased risk for reintubation when treated with preventive HFNC (OR 2.47 [95%CI 1.18–5.15]).

Conclusions

Patients with ≥ 4 risk factors for reintubation may benefit more from preventive NIV. Based on this result, HFNC may not be the optimal preventive therapy in overweight patients. Specific trials are needed to confirm these results.

P-080 Intrauterine insemination (IUI) success rates in patients with suboptimal total processed motile sperm count (TPMSC) using a second consecutive semen sample

Study question

Is it effective to request a second consecutive semen sample in patients with less than 1 million TPMSC in a first semen sample for IUI?

Summary answer

In men with TPMSC under one million, the issuing of a second consecutive sample reached pregnancy rates similar to those published for IUI.

What is known already

IUI offers a comparable cumulative live birth rate in 3-4 cycles compared to IVF and can be preferred as a cost-effective first-line treatment in mild male factor or unexplained infertility. The quality of the processed semen sample is an important factor for the IUI success.

The WHO recommends an abstinence period to ensure best quality of semen samples. However, it has been observed that when men with moderate male factor who are unable to meet the minimum requirements for IUI are asked to produce a second sample better counts are obtained; questioning the time correlation between abstinence and semen quality.

Study design, size, duration

This was a retrospective study conducted in the reproductive medicine unit of a private hospital in Chile between July 2015 and March 2021. All patients who underwent IUI in the study period that had an TPMSC less than 1 million in the eyaculate and to whom a second consecutive sample was requested were included.

Participants/materials, setting, methods

118 patients who underwent 140 IUI cycles were included in the study. All the patients with an PMSC under 1 million at the time of the IUI were requested a second consecutive semen sample within an hour or two from the previous eyaculate. The second samples were processed and used for insemination. The primary outcome was pregnancy rate. The secondary outcomes were semen quality (TPMSC of first and second semen samples).

Main results and the role of chance

Between 2015 and 2021 there were 140 IUI cycles in which a second consecutive semen sample was requested, including 118 patients. Overall 17 pregnancies were achieved. The pregnancy rate per cycle was 12,14% and the pregnancy rate per patient was 14,4%. The live birth rate per patient was 10,2%.

Regarding the sperm sample analysis, the median TPMSC of the first semen sample was 261.437. The median PMSC of the second consecutive sample was 7.315.000. 126 patients had an TPMSC of 0 in the first semen sample while only 9 patients had an IMSC of 0 in the second sample. In five cases a third consecutive sample was requested of which 4 patients had their cycles canceled because they did not meet the target PMSC. One patient had an TPMSC of 1.687.000 in the third sample.

Finally, of the 118 patients who did not meet the requirements for IUI with the first sample, only 19 cycles were canceled.

Limitations, reasons for caution

The study has the limitation of being a retrospective and descriptive study with no contol group. Also the group is heterogeneous because it includes patients with different female factors for infertility.

Wider implications of the findings

In developing countries and low-income settings the IUI remains a more accessible alternative in patients with infertility. Routinely recollecting a second semen sample in men with TPMSC &lt;1 million would reduce cycle cancellation rates due to not achieving an optimal TPMSC, reaching pregnancy rates similar to those published for IUI.

Trial registration number

Not applicable

Preclinical dosimetry in proton minibeam radiation therapy: robustness analysis and guidelines

Purpose

Proton minibeam radiation therapy (pMBRT) is a new radiotherapy approach that has shown a significant increase in the therapeutic window in glioma‐bearing rats compared to conventional proton therapy. The dosimetry of pMBRT is challenging and error prone due to the submillimetric beamlet sizes used. The aim of this study was to perform a robustness analysis on the setup parameters utilized in current preclinical trials and provide guidelines for reproducible dosimetry. The results of this work are intended to guide upcoming implementations of pMBRT worldwide, as well as pave the way for future clinical implementations.

Methods

Monte Carlo simulations and experimental data were used to evaluate the impact of variations in setup parameters and uncertainties in collimator specifications on lateral pMBRT dose distributions. The value of each parameter was modified individually to evaluate their effect on dose distributions. Experimental dosimetry was performed by means of high‐resolution detectors, that is, radiochromic films, the IBA Razor and the Microdiamond detector. New guidelines were proposed to optimize the experimental setup in pMBRT studies and perform reproducible dosimetry.

Results

The sensitivity of dose distributions to uncertainties and variations in setup parameters was quantified. Quantities that define pMBRT lateral profiles (i.e., the peak‐to‐valley dose ratio [PVDR], peak and valley doses, and peak width) are significantly influenced by small‐scale fluctuations in several of those parameters. The setup implemented at the Orsay proton therapy center for pMBRT irradiation was optimized to increase PVDRs and peak symmetry. In addition, we proposed guidelines to perform accurate and reproducible dosimetry in preclinical studies.

Conclusions

This study revealed the importance of adopting guidelines and protocols tailored to the distinct dose delivery method and dose distributions in pMBRT. This new methodology leads to reproducible dosimetry, which is imperative in preclinical trials. The results and guidelines presented in this manuscript can ease the initiation of pMBRT investigations in other centers.

First Evaluation of Temporal and Spatial Fractionation in Proton Minibeam Radiation Therapy of Glioma-Bearing Rats

Simple Summary

Proton minibeam radiation therapy (pMBRT) is a novel therapeutic approach based on a distinct dose delivery method: the dose distributions follow a pattern with regions of peaks (high doses) and valleys (low doses). pMBRT was shown to be able to widen the therapeutic window in glioma-bearing rats. In previous studies the irradiation was performed in one single fraction. The work reported in this manuscript is the first evaluation detailing the response of glioma-bearing rats to a temporal fractionation in proton minibeam radiation therapy, delivered under a crossfire geometry. A significant increase of the median survival time was obtained when the dose was delivered over two sessions as opposed to in a single fraction. This result could facilitate the path towards pMBRT treatments.

Abstract

(1) Background: Proton minibeam radiation therapy (pMBRT) is a new radiotherapy technique using spatially modulated narrow proton beams. pMBRT results in a significantly reduced local tissue toxicity while maintaining or even increasing the tumor control efficacy as compared to conventional radiotherapy in small animal experiments. In all the experiments performed up to date in tumor bearing animals, the dose was delivered in one single fraction. This is the first assessment on the impact of a temporal fractionation scheme on the response of glioma-bearing animals to pMBRT. (2) Methods: glioma-bearing rats were irradiated with pMBRT using a crossfire geometry. The response of the irradiated animals in one and two fractions was compared. An additional group of animals was also treated with conventional broad beam irradiations. (3) Results: pMBRT delivered in two fractions at the biological equivalent dose corresponding to one fraction resulted in the highest median survival time, with 80% long-term survivors free of tumors. No increase in local toxicity was noted in this group with respect to the other pMBRT irradiated groups. Conventional broad beam irradiations resulted in the most severe local toxicity. (4) Conclusion: Temporal fractionation increases the therapeutic index in pMBRT and could ease the path towards clinical trials.

Risk and vulnerability assessment in coastal environments applied to heritage buildings in Havana (Cuba) and Cadiz (Spain)

In this paper, diagnostic tools are utilized to conduct a vulnerability analysis of monuments located in a coastal environment in accordance with a raft of standards drawn up by the International Organization for Standardization (ISO) 31000, in order to identify the main risks for Cultural Heritage in Havana (Cuba) and Cadiz (Spain). Vulnerability analysis is based on a Leopold matrix, which models the relationship between major hazards and pathologies in order to evaluate coastal influence and the risks for the conservation of cultural heritage. The quantitative matrix allows for a cause-effect analysis to be conducted for the main scenarios, related to the state of conservation. These relationships are a key step in risk assessment and treatment strategies. Major hazards have been identified by different public bodies and agencies to provide information about the probability and intensity of these variables in the vulnerability matrix. The combination of vulnerability index assessment, which depends on intrinsic variables and environmental scenarios, and knowledge of the main hazards in Havana and Cadiz, has provided useful tools to conduct risk assessments for cultural heritage conservation in coastal environments, where climate conditions, geomorphology and social issues are the main hazards, while vulnerability is associated with conservation plans. These tools provide information that will enable decision-makers in different coastal environments to prioritize strategies for cultural heritage preservation.

Cost-effectiveness of Lutetium [177Lu] oxodotreotide versus best supportive care with octreotide in patients with midgut neuroendocrine tumors in France

BACKGROUND AND AIMS

In France, there are approximately 2,400 new cases of neuroendocrine tumors (NETs) annually. Peptide receptor radionuclide therapy with ¹⁷⁷Lu-Dotatate plus long-acting repeatable [LAR] octreotide 30 mg has been shown to significantly improve progression-free survival and overall survival relative to high-dose octreotide LAR 60 mg in patients with unresectable or metastatic progressive midgut NETs. A long-term cost-effectiveness analysis was performed to assess whether ¹⁷⁷Lu-Dotatate is a cost-effective option versus octreotide 60 mg for patients with unresectable/metastatic progressive midgut NETs from the perspective of French healthcare payer.

METHODS

The analysis was performed using a three-state partitioned survival model. In the base case analysis ¹⁷⁷Lu-Dotatate plus octreotide LAR 30 mg was compared with high-dose octreotide LAR 60 mg in patients with midgut NETs. Survival data were obtained from the phase III NETTER-1 trial in patients with metastatic midgut NETs. Future costs and clinical outcomes were discounted at 4% per annum. One-way deterministic and probabilistic sensitivity analyses were performed.

RESULTS

In the base case analysis, for patients with midgut NETs, ¹⁷⁷Lu-Dotatate treatment improved quality-adjusted life expectancy by 1.21 quality-adjusted life years (QALYs) relative to octreotide LAR 60 mg and the lifetime treatment costs were EUR 50,784 higher with ¹⁷⁷Lu-Dotatate resulting in an incremental cost-effectiveness ratio (ICER) of EUR 42,106 per QALY gained versus octreotide LAR 60 mg. When compared with everolimus, ¹⁷⁷Lu-Dotatate was associated with an ICER of EUR 59,769 per QALY gained. Sensitivity analyses showed that the results were sensitive to methods used to extrapolate survival data.

CONCLUSIONS

For patients with advanced progressive midgut NETs ¹⁷⁷Lu-Dotatate is likely to be considered a cost-effective option versus octreotide 60 mg from the perspective of the French healthcare payer.

Effects of dietary inclusion of Opuntia ficus-indica on the glycemia and productive performance in lactating sows

Sows with increased blood glucose during late gestation may have decreased feed intake in lactation. Supplying dietary fibre to the sow reportedly modulates blood glucose and improves feed intake. The objective of this study was to evaluate the effects of dietary inclusion of cactus (Opuntia ficus-indica) on the regulation of blood glucose and productive performance in lactating sows. Data from 52 hybrid sows were analysed. The sows were divided into two groups, namely a control group (CG), that is, sows fed conventionally; and an experimental group (EG), that is, sows fed commercial feed plus cacti. Blood glucose in late gestation, and feed intake, milk production and milk quality, development of the piglet, energy balance, post-weaning body weight balance and the interval from weaning to oestrus were recorded. Preprandial blood glucose was 55.9 mg per dL in EG and 71.4 in CG. Sows on EG had greater daily feed intake and lower negative energy balance (5.4 kg/day and -2.8 MJ/day) than those on CG (4.5 kg/day and -9.4 MJ/day). Sows fed EG produced more milk (8.6 L/day) than those on CG (8.1 L/day). The quality of milk produced and the weaning weight of piglets were similar for the two groups. Body weight balance after weaning was greater for sows fed EG, 3.5% versus -1.5% in those fed CG. The weaning to oestrus interval was 0.6 days less for sows fed EG than those fed CG. Feeding cactus to lactating sows regulated blood glucose, which improved most of their productive indicators.Keywords: cactus, dietary fibre, energy balance, hypophagia, piglet

Condición corporal en caballos de rodeo chileno de elite: estudio preliminar

El objetivo de este estudio fue caracterizar la condición corporal de caballos de rodeo chileno de elite en competencia. Se eligieron al azar 48 caballos raza chilena (15 hembras, 24 machos enteros y 9 machos castrados) participantes del 64º Campeonato Nacional de Rodeo Chileno. La condición corporal de cada caballo se evaluó por inspección visual y palpación según el sistema de Henneke. El rendimiento deportivo se registró como clasificados o no clasificados en la final del campeonato. Se construyeron tablas de frecuencia para la condición corporal por género y por rendimiento deportivo, se calcularon modas como descriptores de tendencia central y se comparó la condición corporal por género y rendimiento deportivo mediante la prueba de Kruskal-Wallis (p < 0,05). La condición corporal presentó una moda de 7, con un rango de 5 a 8. El 87,5% de los caballos tenía condición corporal entre 6 y 7 y se detectó un 6,3% de individuos obesos. No se encontraron diferencias significativas en relación al género ni rendimiento deportivo. Este es el primer estudio que reporta la condición corporal en caballos de rodeo chileno de élite y los resultados sugieren que los valores más frecuentes para esta variable en la raza están entre 6 a 7 puntos.

[Long-term results of the early endoscopic treatment of acquired tracheal-subglottic stenosis: 10 years of experience]

INTRODUCTION

Acquired stenosis of the airway is a common complication after endotracheal intubation. Endoscopic dilation has been accepted as the treatment of choice in cases detected precociously. Our goal is to know the current status of the patients treated in our hospital with endoscopic dilation in the last 10 years.

MATERIAL AND METHODS

Retrospective cohort study of patients with subglottic and tracheal acquired stenosis (STAS) early treated endoscopically with balloon dilation at our center in the last 10 years. Bronchoscopy control at 2 weeks, a month, 3 and 6 months post-dilation were performed and later on depending on the symptoms.

RESULTS

32 patient were treated in the period considered. The median age was 4.5 (3-120) months. There were necessary 2.5 (1-5) dilations per patient. All cases were extubated in the operating room or in the following 24 hours. There were no complications during the procedure. Follow-up time was 6 (1-10) years. Only 1 of the 32 patients have had recurrence of stenosis 2 years after, it was secondary to reintubations due to new surgical interventions; which it was dilated successfully.

CONCLUSIONS

Early endoscopic dilation in the acquired airway stenosis is a safe and effective long-term procedure. The results support the use of this technique as a treatment of choice in these patients.

Equine mesenchymal stem cells derived from endometrial or adipose tissue share significant biological properties, but have distinctive pattern of surface markers and migration

Adult stromal mesenchymal stem cells (MSCs) have been postulated as responsible for cell renewal in highly and continuously regenerative tissues such as the endometrium. MSCs have been identified in the endometrium of many species including humans, rodents, pets and some farm animals, but not in horses. The objective of this work was to isolate such cells from the endometrium of mares and to compare their main biological attributes with horse adipose-derived MSCs. Here we successfully isolated and characterized endometrial MSCs (eMSCs) from mares. Said cells showed fibroblast-like morphology, grew on plastic, had doubling population times of 46.4 ± 3.38 h, underwent tri-lineage (osteo, chondro and adipogenic) differentiation after appropriate inductions, migrated toward the attraction of fetal calf serum and displayed a pattern of surface markers commonly accepted for horse MSCs. All these are properties of MSCs. Some of these attributes were shared with equine adipose-derived MSCs, but the migration pattern of eMSC at 12 and 24 h after stimulation was reduced in comparison with adipose MSCs. Also, expression of CD44, CD90 and MHCI surface markers were dramatically down-regulated in eMSCs. In conclusion, equine-derived endometrial MSC share biological attributes with adipose MSC of this species, but displayed a different surface marker phenotype and an impaired migration ability. Conceivably, this phenotype is distinctive for MSC of this origin.

Therapeutic possibilities for urolithiasis in childhood

OBJECTIVES

We present our case studies on paediatric urolithiasis, the techniques employed in its treatment and its results.

MATERIAL AND METHODS

A retrospective study of paediatric urolithiasis of the upper urinary tract (UUT) treated at our centre between 2003 and 2014. We recorded demographic, clinical, diagnostic and therapeutic data and the complications. The therapeutic plan was recorded as isolated (extracorporeal lithotripsy, ureterorenoscopy, nephrolithotomy or surgery) or combined therapy.

RESULTS

We examined 41 renal/urethral units in 32 patients. The median age was 5 years (range, 11 months-14 years). The mean size was 12.9cm (±7.3mm). The locations were as follows: 23 (56%) in the renal pelvis (staghorn in 15 cases), 10 (24) in lower calyx and 8 (20%) in the urethra. We performed 80 procedures, with no differences in the age groups, which resulted in 12 complications (15%) but no septic condition secondary to lithotripsy. Stone removal from the urethra had a 100% success rate with the ureterorenoscopy. The overall cure rate was 90%.

CONCLUSION

The paediatric urolithiasis approach offers multiple alternatives. It is therefore important to tailor the procedure according to the size, location and composition of the stone. In our centre, the use of paediatric extracorporeal shock wave lithotripsy is safer. Ureterorenoscopy, semirigid or flexible, provides excellent results in ureters. Percutaneous nephrolithotomy with minimal access can be performed on small children and nursing infants.

Late diagnosis of posterior urethral valves

CLINICAL PROBLEM

We diagnosed 8 patients with late-stage posterior urethral valves (PUV) between 1 and 14 years of age. Five patients complained of symptoms related to voiding dysfunction. The other 3 patients required urethrocystoscopy for other reasons (hypospadias fistulae, difficulty with catheterisation and high-grade vesicoureteral reflux [VUR]). A second review of the first 2 patients' medical history showed voiding dysfunction symptoms. All patients underwent preoperative ultrasonography: 3 patients had normal results and 5 had renal or vesical disorders. The diagnosis was reached through voiding cystourethrogram (VCUG), and 4 patients underwent urodynamic studies. The diagnosis was confirmed by urethrocystoscopy, performing valve electrofulguration. We performed urethrocystoscopy during the check-ups at 3-6 weeks and observed no stenosis. The symptoms disappeared for all patients after 20 months of follow-up. The patient with VUR was cured. The ultrasounds showed no progression of the renal involvement and showed improvement in the vesical involvement. The velocimetries during check-ups presented curves within normal ranges.

DISCUSSION

Most children with PUV are diagnosed through ultrasound during the neonatal period. Some patients present PUV at later ages with diverse symptoms, which impedes its diagnosis. We should suspect PUV in male patients with symptoms of voiding dysfunction, either when they have normal or pathological results from ultrasounds or VCUG. We recommend performing urethrocystoscopy to rule out urethral obstruction.

[Cervico-sternotomy for thoracic inlet conditions in children]

BACKGROUND/AIM

Neither cervicotomy nor postero-lateral thoracotomy allow safe surgical access to the lower cervical spine and high posterior mediastinum with full control of the vascular and neural structures involved. We report our favorable experience with cervico-sternotomy for accessing this region.

PATIENTS AND METHODS

Six patients were operated upon between 1998 and 2011 for either removal of huge cervico-thoracic neural ganglioneuromas (n = 2) or anterior arthrodesis for congenital (n = 2), neuropathic (n = 1) or osteolytic scoliosis (n = 1). In all cases, cervicotomy was followed by sternotomy, thymectomy, division of the innominate vein and dissection of jugular veins, carotid arteries and vagus nerves.

RESULTS

The tumors measured 10.9 x 3.9 x 8.7 cm and 8 x 6 x 5 cm, and involved the paravertebral chain from the aortic arch to the base of the skull and from the left lung hilus to the thyroid region respectively. In the scoliosis patients, anterior vertebral fixation between C5 and T5 was readily feasible. Blood transfusion was avoided. Horner's syndrome and transient lymphedema were the only complications. Median operative time was 210 minutes (range 180-240 minutes) and median estimated blood loss was 2.7 cc/kg (0-13.8 cc/kg). Median hospital stay was 7 days (range 5-18 days).

CONCLUSIONS

Cervico-sternotomy is an optimal approach for this anatomical region in children. It offers better exposure of the anterior cervico-thoracic spine and the thoracic inlet than cervicotomy or thoracotomy. Control of the nervous and vascular structures was safely achieved in all cases and postoperative discomfort was surprisingly limited.

Switching from twice-daily raltegravir plus tenofovir disoproxil fumarate/emtricitabine to once-daily elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate in virologically suppressed, HIV-1-infected subjects: 48 weeks data

BACKGROUND

Pill burden, dosing frequency, and concerns about safety and tolerability are important obstacles to maintaining adequate medication adherence. Raltegravir (RAL) is indicated for twice-daily dosing and when taken with emtricitabine (FTC)/tenofovir disoproxil fumarate (TDF), it becomes a twice-daily multiple-tablet regimen. Elvitegravir (EVG)/cobicistat (COBI)/FTC/TDF, STB, is the first approved once-a-day integrase strand transfer inhibitor (INSTI) containing single-tablet regimen that combines EVG, an INSTI, and COBI, a novel pharmacoenhancer, with the preferred nucleos(t)ide backbone of FTC/TDF.

METHODS

This was a 48-week prospective, single-arm open-label study of the switch to STB in virologically sup-pressed HIV-1-infected adult patients on FTC/TDF and twice-daily RAL for at least 6 months. Objectives were to evaluate the tolerability and safety of a regimen simplification to once-a-day STB, while maintaining viral suppression through 48 weeks.

RESULTS

Forty-eight individuals in the United States were enrolled. The median age was 44 years, 96% were male, and 83% were White. The median time on RAL + FTC/TDF treatment prior to enrollment was 34 months. Ninety-six percent of participants cited regimen simplification as the reason to enroll in the switch study. At base-line, the median CD4 count was 714 cell/µL and estimated glomerular filtration rate (eGFR) was 105 mL/min. At week 48, all assessed study participants remained viro-logically suppressed to the lower limit of quantification (HIV-1 RNA<50 copies/mL) and maintained high CD4 cell count (median, 751 cells/mL) and stable eGFR (median, 100.5 mL/min). STB was well tolerated with no discontinuations, no study drug-related serious adverse events, and no study drug-related grade 3/4 adverse events.

CONCLUSIONS

All participants switching to 1 tablet once-a-day STB from a twice-daily RAL + FTC/TDF regimen remained virologically suppressed. STB was well tolerated. Switching to STB may be a viable option for virologically suppressed patients wanting to simplify from a twice-daily RAL-containing regimen.

Colon cancer therapy: recent developments in nanomedicine to improve the efficacy of conventional chemotherapeutic drugs

The number of patients with colorectal cancer, the third most frequently diagnosed malignancy in the world, has increased markedly over the past 20 years and will continue to increase in the future. Despite recent advances in chemotherapy, currently used anticancer molecules are unable to improve the prognosis of advanced or recurrent colorectal cancer, which remains incurable. The transport of classical drugs by nanoparticles has shown great promise in terms of improving drug distribution and bioavailability, increasing tissue half-life and concentrating anticancer molecules in the tumor mass, providing optimal drug delivery to tumor tissue, and minimizing drug toxicity, including those effects associated with pharmaceutical excipients. In addition, colon cancer targeting may be improved by incorporating ligands for tumor-specific surface receptors. Similarly, nanoparticles may interact with key drug-resistance molecules to prevent a reduction in intracellular drug levels drug. Recently published data have provided convincing pre-clinical evidence regarding the potential of active-targeted nanotherapeutics in colon cancer therapy, although, unfortunately, only a few of these therapies have been translated into early-phase clinical trials. As nanotechnology promises to be a new strategy for improving the prognosis of colon cancer patients, it would be very useful to analyze recent progress in this field of research. This review discusses the current status of nanoparticle-mediated cancer-drug delivery, the challenges restricting its application, and the potential implications of its use in colon cancer therapy.

Regulatory systems in bone marrow for hematopoietic stem/progenitor cells mobilization and homing

Regulation of hematopoietic stem cell release, migration, and homing from the bone marrow (BM) and of the mobilization pathway involves a complex interaction among adhesion molecules, cytokines, proteolytic enzymes, stromal cells, and hematopoietic cells. The identification of new mechanisms that regulate the trafficking of hematopoietic stem/progenitor cells (HSPCs) cells has important implications, not only for hematopoietic transplantation but also for cell therapies in regenerative medicine for patients with acute myocardial infarction, spinal cord injury, and stroke, among others. This paper reviews the regulation mechanisms underlying the homing and mobilization of BM hematopoietic stem/progenitor cells, investigating the following issues: (a) the role of different factors, such as stromal cell derived factor-1 (SDF-1), granulocyte colony-stimulating factor (G-CSF), and vascular cell adhesion molecule-1 (VCAM-1), among other ligands; (b) the stem cell count in peripheral blood and BM and influential factors; (c) the therapeutic utilization of this phenomenon in lesions in different tissues, examining the agents involved in HSPCs mobilization, such as the different forms of G-CSF, plerixafor, and natalizumab; and (d) the effects of this mobilization on BM-derived stem/progenitor cells in clinical trials of patients with different diseases.

How is gene transfection able to improve current chemotherapy? The role of combined therapy in cancer treatment

Despite advances in cancer treatment, a large number of patients eventually develop metastatic disease that is generally incurable. Systemic chemotherapy remains the standard treatment for these patients. Several chemotherapeutic combinations have proven effective in the management of cancer. Paradoxically, although the purpose of polychemotherapy is to improve the prognosis and prolong the survival of patients, it often carries considerable toxicity that causes substantial adverse symptoms. For this reason, a major goal of cancer research is to improve the effectiveness of these cytotoxic agents and reduce their adverse effects. Gene transfer has been proposed as a new strategy to enhance the efficacy of anti-tumor drugs in the treatment of intractable or metastatic cancers. In fact, the association of gene therapy and drugs (combined therapy) has been reported to increase the anti-proliferative effect of classical treatments in lung, bladder, pancreatic, colorectal and breast cancers, among others. Various especially promising therapies have been proposed in this context, including the use of suicide genes, antisense oligonucleotides, ribozymes and RNA interference. In this chapter, we review recent progress in the development of novel anti-cancer strategies that associate cytotoxic agents with gene transfer to enhance their antitumor effect.

Measuring higher-order modes in a low-loss, hollow-core, photonic-bandgap fiber

We perform detailed measurements of the higher-order-mode content of a low-loss, hollow-core, photonic-bandgap fiber. Mode content is characterized using Spatially and Spectrally resolved (S2) imaging, revealing a variety of phenomena. Discrete mode scattering to core-guided modes are measured at small relative group-delays. At large group delays a continuum of surface modes and core-guided modes can be observed. The LP11 mode is observed to split into four different group delays with different orientations, with the relative orientations preserved as the mode propagates through the fiber. Cutback measurements allow for quantification of the loss of different individual modes. The behavior of the modes in the low loss region of the fiber is compared to that in a high loss region of the fiber. Finally, a new measurement technique is introduced, the sliding-window Fourier transform of high-resolution transmission spectra of hollow-core fibers, which displays the dependence of HOM content on both wavelength and group delay. This measurement is used to illustrate the HOM content as function of coil diameter.