Impact of respiratory motion on proton pencil beam scanning FLASH radiotherapy: anin silicoand phantom measurement study

OBJECTIVE

To investigate the effects of respiratory motion on the delivered dose in the context of proton pencil beam scanning (PBS) transmission FLASH-RT by simulation and phantom measurements. 
Approach: An in-house simulation code was employed to perform in silico simulation of 2D dose distributions for clinically relevant proton PBS transmission FLASH-RT treatments. A moving simulation grid was introduced to investigate the impacts of various respiratory motion and treatment delivery parameters on the dynamic PBS dose delivery. A strip-ionization chamber array detector and an IROC motion platform were employed to perform phantom measurements of the 2D dose distribution for treatment fields similar to those used for simulation. 
Main results: Clinically relevant respiratory motion and treatment delivery parameters resulted in degradation of the delivered dose compared to the static delivery as translation and distortion. Simulation showed that the gamma passing rates (2 mm/2% criterion) and target coverage (V100%) could drop below 50% and 80%, respectively, for certain scenarios if no mitigation strategy was used. The gamma passing rates and target coverage could be restored to more than 95% and 98%, respectively, for short beams delivered at the maximal inhalation or exhalation phase. The simulation results were qualitatively confirmed in phantom measurements with the motion platform. 
Significance: Respiratory motion could cause dose quality degradation in a clinically relevant proton PBS transmission FLASH-RT treatment if no mitigation strategy is employed, or if an adequate margin is not given to the target. Besides breath-hold, gated delivery can be an alternative motion management strategy to ensure high consistency of the delivered dose while maintaining minimal dose to the surrounding normal tissues. To the best of our knowledge, this is the first study on motion impacts in the context of proton transmission FLASH radiotherapy.

Comprehensive Evaluation of Carbon-Fiber-Reinforced Polyetheretherketone (CFR-PEEK) Spinal Hardware for Proton and Photon Planning

Purpose: To evaluate a novel spine implant, carbon-fiber-reinforced polyetheretherketone (CFR-PEEK), for proton and photon treatment planning. Materials and Methods: We compared target coverage and sparing of organs-at-risk (OARs) for a spinal phantom with 4 different spine configurations: (a) normal (no implant); (b) Titanium; (c) CFR-PEEK; and (d) hybrid (CFR-PEEK with Titanium tulip head). The spinal phantom was imaged via computed tomography (CT) scan, and the iterative Metal Artifact Reduction (iMAR) CT set was used for planning. A representative spinal chordoma target and associated OARs were contoured. The prescription dose was 50 Gy to the initial target volume, followed by a 24 Gy boost, for which multi-field optimization (MFO) proton plans were developed with a 3 mm setup and 3.5% range uncertainties. For photon planning, volumetric modulated arc therapy (VMAT) plans were developed for the initial and boost plans. OAR dose constraints were set according to our institutional guidelines. Results: For the 4 spine configurations, the proton plans achieved similar nominal target coverage and OARs sparing. While evaluating coverage and OAR dose under uncertainty scenario analysis for initial clinical target volume (CTV) 50 Gy 95% and 90% coverage, higher means and the narrower band of doses variations were achieved for the normal and CFR-PEEK plans. Similarly, uncertainty analysis of spinal cord D_max showed tighter distribution for normal and CFR-PEEK plans. Overall plan quality showed no significant difference for photon planning when compared to normal spine versus other inserts. However, for proton planning, there is a larger difference for the normal spine insert scenario versus the Titanium insert scenario. For each insert scenario comparison between photon and proton plans, there was a larger difference for OARs: heart and spinal cord. Conclusion: The CFR-PEEK implant has similar clinical properties to a normal spine for proton planning, allowing us to pass protons through the material and achieve superior target coverage and OAR sparing under nominal and uncertainty conditions.

VA-Radiation Oncology Quality Surveillance Program

PURPOSE

We sought to develop a quality surveillance program for approximately 15,000 US veterans treated at the 40 radiation oncology facilities at the Veterans Affairs (VA) hospitals each year.

METHODS AND MATERIALS

State-of-the-art technologies were used with the goal to improve clinical outcomes while providing the best possible care to veterans. To measure quality of care and service rendered to veterans, the Veterans Health Administration established the VA Radiation Oncology Quality Surveillance program. The program carries forward the American College of Radiology Quality Research in Radiation Oncology project methodology of assessing the wide variation in practice pattern and quality of care in radiation therapy by developing clinical quality measures (QM) used as quality indices. These QM data provide feedback to physicians by identifying areas for improvement in the process of care and identifying the adoption of evidence-based recommendations for radiation therapy.

RESULTS

Disease-site expert panels organized by the American Society for Radiation Oncology (ASTRO) defined quality measures and established scoring criteria for prostate cancer (intermediate and high risk), non-small cell lung cancer (IIIA/B stage), and small cell lung cancer (limited stage) case presentations. Data elements for 1567 patients from the 40 VA radiation oncology practices were abstracted from the electronic medical records and treatment management and planning systems. Overall, the 1567 assessed cases passed 82.4% of all QM. Pass rates for QM for the 773 lung and 794 prostate cases were 78.0% and 87.2%, respectively. Marked variations, however, were noted in the pass rates for QM when tumor site, clinical pathway, or performing centers were separately examined.

CONCLUSIONS

The peer-review protected VA-Radiation Oncology Surveillance program based on clinical quality measures allows providers to compare their clinical practice to peers and to make meaningful adjustments in their personal patterns of care unobtrusively.

Surgery after chemoradiotherapy in patients with stage III (N2 or N3, excluding T4) non-small-cell lung cancer: a systematic review

Background

Chemoradiation with curative intent is considered the standard of care in patients with locally advanced, stage iii non-small-cell lung cancer (nsclc). However, some patients with stage iii (N2 or N3, excluding T4) nsclc might be eligible for surgery. The objective of the present systematic review was to investigate the efficacy of surgery after chemoradiotherapy compared with chemoradiotherapy alone in patients with potentially resectable locally advanced nsclc.

Methods

A search of the medline, embase, and PubMed databases sought randomized controlled trials (rcts) comparing surgery after chemoradiotherapy with chemoradiotherapy alone in patients with stage iii (N2 or N3, excluding T4) nsclc.

Results

Three included rcts consistently found no statistically significant difference in overall survival between patients with locally advanced nsclc who received surgery and chemoradiotherapy or chemoradiotherapy alone. Only one rct found that progression-free survival was significantly longer in patients treated with chemoradiation and surgery (hazard ratio: 0.77; 95% confidence interval: 0.62 to 0.96). In a post hoc analysis of the same trial, the overall survival rate was higher in the surgical group than in matched patients in a chemoradiation-only group if a lobectomy was performed (p = 0.002), but not if a pneumonectomy was performed. Furthermore, fewer treatment-related deaths occurred in patients who underwent lobectomy than in those who underwent pneumonectomy.

Conclusions

For patients with locally advanced nsclc, the benefits of surgery after chemoradiation are uncertain. Surgery after chemoradiation for patients who do not require a pneumonectomy might be an option.

Morpholino-mediated SOD1 reduction ameliorates an amyotrophic lateral sclerosis disease phenotype

Neurotoxicity due to the accumulation of mutant proteins is thought to drive pathogenesis in neurodegenerative diseases. Mutations in superoxide dismutase 1 (SOD1) are linked to familial amyotrophic lateral sclerosis (fALS); these mutations result in progressive motor neuron death through one or more acquired toxicities. Interestingly, SOD1 is not only responsible for fALS but may also play a significant role in sporadic ALS; therefore, SOD1 represents a promising therapeutic target. Here, we report slowed disease progression, improved neuromuscular function, and increased survival in an in vivo ALS model following therapeutic delivery of morpholino oligonucleotides (MOs) designed to reduce the synthesis of human SOD1. Neuropathological analysis demonstrated increased motor neuron and axon numbers and a remarkable reduction in astrogliosis and microgliosis. To test this strategy in a human model, we treated human fALS induced pluripotent stem cell (iPSC)-derived motor neurons with MOs; these cells exhibited increased survival and reduced expression of apoptotic markers. Our data demonstrated the efficacy of MO-mediated therapy in mouse and human ALS models, setting the stage for human clinical trials.

Motor neurons with differential vulnerability to degeneration show distinct protein signatures in health and ALS

The lethal disease amyotrophic lateral sclerosis (ALS) is characterized by the loss of somatic motor neurons. However, not all motor neurons are equally vulnerable to disease; certain groups are spared, including those in the oculomotor nucleus controlling eye movement. The reasons for this differential vulnerability remain unknown. Here we have identified a protein signature for resistant oculomotor motor neurons and vulnerable hypoglossal and spinal motor neurons in mouse and man and in health and ALS with the aim of understanding motor neuron resistance. Several proteins with implications for motor neuron resistance, including GABAA receptor α1, guanylate cyclase soluble subunit alpha-3 and parvalbumin were persistently expressed in oculomotor neurons in man and mouse. Vulnerable motor neurons displayed higher protein levels of dynein, peripherin and GABAA receptor α2, which play roles in retrograde transport and excitability, respectively. These were dynamically regulated during disease and thus could place motor neurons at an increased risk. From our analysis is it evident that oculomotor motor neurons have a distinct protein signature compared to vulnerable motor neurons in brain stem and spinal cord, which could in part explain their resistance to degeneration in ALS. Our comparison of human and mouse shows the relative conservation of signals across species and infers that transgenic SOD1G93A mice could be used to predict mechanisms of neuronal vulnerability in man.

Human motor neuron generation from embryonic stem cells and induced pluripotent stem cells

Motor neuron diseases (MNDs) are a group of neurological disorders that selectively affect motor neurons. There are currently no cures or efficacious treatments for these diseases. In recent years, significant developments in stem cell research have been applied to MNDs, particularly regarding neuroprotection and cell replacement. However, a consistent source of motor neurons for cell replacement is required. Human embryonic stem cells (hESCs) could provide an inexhaustible supply of differentiated cell types, including motor neurons that could be used for MND therapies. Recently, it has been demonstrated that induced pluripotent stem (iPS) cells may serve as an alternative source of motor neurons, since they share ES characteristics, self-renewal, and the potential to differentiate into any somatic cell type. In this review, we discuss several reproducible methods by which hESCs or iPS cells are efficiently isolated and differentiated into functional motor neurons, and possible clinical applications.

Epidemiology of influenza-associated hospitalization in adults, Toronto, 2007/8

The purpose of this investigation was to identify when diagnostic testing and empirical antiviral therapy should be considered for adult patients requiring hospitalization during influenza seasons. During the 2007/8 influenza season, six acute care hospitals in the Greater Toronto Area participated in active surveillance for laboratory-confirmed influenza requiring hospitalization. Nasopharyngeal (NP) swabs were obtained from patients presenting with acute respiratory or cardiac illness, or with febrile illness without clear non-respiratory etiology. Predictors of influenza were analyzed by multivariable logistic regression analysis and likelihoods of influenza infection in various patient groups were calculated. Two hundred and eighty of 3,917 patients were found to have influenza. Thirty-five percent of patients with influenza presented with a triage temperature >or=38.0 degrees C, 80% had respiratory symptoms in the emergency department, and 76% were >or=65 years old. Multivariable analysis revealed a triage temperature >or=38.0 degrees C (odds ratio [OR] 3.1; 95% confidence interval [CI] 2.3-4.1), the presence of respiratory symptoms (OR 1.7; 95% CI 1.2-2.4), admission diagnosis of respiratory infection (OR 1.8; 95% CI 1.3-2.4), admission diagnosis of exacerbation of chronic obstructive pulmonary disease (COPD)/asthma or respiratory failure (OR 2.3; 95% CI 1.6-3.4), and admission in peak influenza weeks (OR 4.2; 95% CI 3.1-5.7) as independent predictors of influenza. The likelihood of influenza exceeded 15% in patients with respiratory infection or exacerbation of COPD/asthma if the triage temperature was >or=38.0 degrees C or if they were admitted in the peak weeks during the influenza season. During influenza season, diagnostic testing and empiric antiviral therapy should be considered in patients requiring hospitalization if respiratory infection or exacerbation of COPD/asthma are suspected and if either the triage temperature is >or=38.0 degrees C or admission is during the weeks of peak influenza activity.

Integrating regional and community lung cancer services to improve patient care

Lung cancer is the leading cause of cancer death in Canada. The organization of health care services is central to the delivery of accessible, high-quality medical care and may be one factor that influences patient outcome. An exciting opportunity arose for clinicians to initiate the redesign of lung cancer services provided by three institutions in the Greater Toronto Area. This qualitative report describes the integrated lung cancer network that they developed, the innovation it has facilitated, and the systematic approach being taken to evaluate its impact. Available clinical resources were deployed to restructure services along patient-centred lines and to provide greater access to the specialist lung cancer team. A non-hierarchical clinical network was established that consolidates the lung cancer team. A multi-institutional and multidisciplinary tumour board and comprehensive thoracic oncology clinics are at its core. This innovative organizational paradigm considers all of the available services at each facility and aims to fully integrate specialists across the three institutions, thereby maximizing resource utilization. We believe that this paradigm may have wider applicability. The network is currently working to complete a current program of further service improvements and to objectively assess its impact on patient outcome.

p38alpha blockade inhibits colorectal cancer growth in vivo by inducing a switch from HIF1alpha- to FoxO-dependent transcription

Colorectal cancer cell (CRC) fate is governed by an intricate network of signaling pathways, some of which are the direct target of DNA mutations, whereas others are functionally deregulated. As a consequence, cells acquire the ability to grow under nutrients and oxygen shortage conditions. We earlier reported that p38alpha activity is necessary for proliferation and survival of CRCs in a cell type-specific manner and regardless of their phenotype and genotype. Here, we show that p38alpha sustains the expression of HIF1alpha target genes encoding for glycolytic rate-limiting enzymes, and that its inhibition causes a drastic decrease in ATP intracellular levels in CRCs. Prolonged inactivation of p38alpha triggers AMPK-dependent nuclear localization of FoxO3A and subsequent activation of its target genes, leading to autophagy, cell cycle arrest and cell death. In vivo, pharmacological blockade of p38alpha inhibits CRC growth in xenografted nude mice and azoxymethane-treated Apc(Min) mice, achieving both a cytostatic and cytotoxic effect, associated with high nuclear expression of FoxO3A and increased expression of its target genes p21 and PTEN. Hence, inhibition of p38alpha affects the aerobic glycolytic metabolism specific of cancer cells and might be taken advantage of as a therapeutic strategy targeted against CRCs.

Novel splice isoforms of STRADalpha differentially affect LKB1 activity, complex assembly and subcellular localization

STRADalpha is a pseudokinase that forms a heterotrimeric complex with the scaffolding protein MO25 and the tumor suppressor serine threonine protein kinase LKB1. Mutations in the LKB1 gene are responsible for the Peutz-Jeghers Syndrome (PJS) characterized by a predisposition to hamartomatous polyps and hyperpigmentation of the buccal mucosa. Mutations in LKB1 have also been observed in some sporadic tumours unrelated to PJS. The LKB1/STRAD/MO25 complex is involved in the regulation of numerous signaling pathways including metabolism, proliferation and cellular polarity of human intestinal epithelial cells. Cell polarization, together with tissue-restricted transcription, represents the main feature of enterocyte differentiation. Since a full-length STRADalpha transcript has not been identified thus far in these cells, we evaluated the expression of endogenous STRADalpha in five colorectal cancer cell lines characterized by their diverse ability to differentiate in vitro. We report herein the discovery of several novel splice isoforms of STRADalpha that differentially affect the kinase activity, complex assembly, subcellular localization of LKB1 and the activation of the LKB1-dependent AMPK pathway.

[Alcohol related risk survey about health workers]

The link between drinking and consequent injuries during job activities has been stresses by the most important international organizations and by ISTAT. Luckily, the low 125/01 has opened to "occupational doctor" the possibility of analysing the alcohol related risks among particular working classes, i.e. hospital workers. Thus, it has been conducted a survey in our Hospital in order to understand the entity of the alcohol related risk. The 32.59 of the sample was classified as teetotallers, 45.81% was in the range of low risk probability, while the 24.58% was in the high risk one. It has also been noticed a significant link between the highest level of risk and male employees, but nothing in relation with age or the type of job. In conclusion, this study has represented the first step for our next training programs to reduce the alcohol related risks and give a support to those workers who have already drinking problems.

A novel cell type-specific role of p38alpha in the control of autophagy and cell death in colorectal cancer cells

Cancer develops when molecular pathways that control the fine balance between proliferation, differentiation, autophagy and cell death undergo genetic deregulation. The prospects for further substantial advances in the management of colorectal cancer reside in a systematic genetic and functional dissection of these pathways in tumor cells. In an effort to evaluate the impact of p38 signaling on colorectal cancer cell fate, we treated HT29, Caco2, Hct116, LS174T and SW480 cell lines with the inhibitor SB202190 specific for p38alpha/beta kinases. We report that p38alpha is required for colorectal cancer cell homeostasis as the inhibition of its kinase function by pharmacological blockade or genetic inactivation causes cell cycle arrest, autophagy and cell death in a cell type-specific manner. Deficiency of p38alpha activity induces a tissue-restricted upregulation of the GABARAP gene, an essential component of autophagic vacuoles and autophagosomes, whereas simultaneous inhibition of autophagy significantly increases cell death by triggering apoptosis. These data identify p38alpha as a central mediator of colorectal cancer cell homeostasis and establish a rationale for the evaluation of the pharmacological manipulation of the p38alpha pathway in the treatment of colorectal cancer.

pRb: master of differentiation. Coupling irreversible cell cycle withdrawal with induction of muscle-specific transcription

The protein product of the retinoblastoma (RB) gene is necessary for the completion of the muscle differentiation program and for myogenic basic helix-loop-helix-dependent transcription. In fact, in addition to induction and maintenance of permanent cell cycle withdrawal through negative regulation of E2F-responsive genes involved in proliferation, pRb also plays a positive role in the activation of muscle-specific genes. In pRb-/- myocytes, the expression of late myogenic markers is defective and myoblast fusion into myotubes occurs without irreversible cell cycle exit. This evidence demonstrates only a partial functional redundancy between pRb and its relatives p107 and pRb2/p130, as these pRb-/- multinucleated cells, which display p107 levels higher than normal myotubes, respond to mitogens with cell cycle re-entry and DNA synthesis. At the molecular level, pRb myogenic functions are mediated by cooperation with MyoD, Myocyte enhancer factor 2 (MEF2), High mobility group box protein-1 (HBP1) and histone deacetylase1, affecting chromatin configuration and tissue-specific transcription, and by post-translational modification in response to intracellular signaling cascades.

[Manual lymph drainage of post-mastectomy "big arm"]

We estimate the effectiveness of the manual lymphodrainage in the patients with post-mastectomy lymphedema of the upper limb associated to axillary lymphnodes dissection of the ipsilateral arm. The best results were found in the patients with soft and recent lymphedema (which means that was seen within one year); the worst were found in the chronic hard lymphedema. An important psychological assistance and physiotherapy were required to complete the rehabilitation. However, the physiotherapy was very effective when associated to pressed bandage of the arm, at the end of the LDM therapy. Furthermore, the muscle contraction in the bandage had reinforced the lymphoematic pump effect.

Manipulative therapy in the treatment of benign cervicobrachialgia of mechanical origin

The authors compared two methods of rehabilitation, traditional physical therapy and manual therapy, in the treatment of benign cervicobrachialgia of mechanical origin, typical of young subjects, generally consequent to mild and moderate trauma, occasional strain or incorrect posture repeated in time. A MID (minor intervertebral deficit) is at its origin, characterized by the absence of objective instrumental signs (X-ray, CT scan, MRI) and it is only diagnosed based on clinical history and accurate physical examination of the spine segment involved. A sample of 80 patients was divided at random into two groups: the first group was submitted to traditional physiotherapy, the second to manipulative therapy carried out according to the French method of R. Meigne. The results obtained, which were evaluated by univaried ANOVA and Student's "t" test statistical analysis, showed the greater effectiveness of manipulative treatment, in the short term and in the long term.

Adhesion molecules in gonarthrosis and knee prosthesis aseptic loosening follow-up: possible therapeutic implications

The involvement of the synovium is common in phlogistic processes of various joint diseases. Apart from synoviocytes and the other cells in the synovial tissue, circulating cells recruited from peripheral blood also participate in the phlogistic process. The increased expression of adhesion molecules on both circulating and endothelial cell surface may further this recruitment. We studied 15 patients affected by serious gonarthrosis requiring a prosthetic implant (GPI) and 7 with knee prosthesis aseptic loosening (KPL) to evaluate adhesion molecule expression and phlogistic infiltration in the synovium using immunohistochemistry and microscopic analysis. As control we studied 10 subjects affected by degenerative meniscopathies undergoing a selective arthroscopic surgical meniscectomy. Analysis with Kruskal-Wallis test showed no statistical significant differences in the expression of CD54, CD11a, CD11b and CD18 in three groups examined. The model of variance analysis (Friedman test), showed that CD54 expression is greater in patients with GPI and KPL in comparison with the other molecules. Adhesion molecules and their functions are important in arthropathies not only because their evaluation can allow us to identify the degree of inflammation and to predict its evolution, but also because pharmacological control of their expression could have important therapeutic implications.

[Hemodynamic and respiratory changes during hip and knee arthroplasty. An echocardiographic study]

BACKGROUND

The "bone cement implantation syndrome" is a rare but severe complication observed especially during the insertion of cemented prostheses in hip and knee replacement surgery. Several mechanisms are involved: effects of methylmethacrilate, embolism of fat, air and bone marrow, and release of tissue thromboplastin during acetabular and femoral reaming. Aim of this study was to detect embolic events, right heart impairment, hemodynamic and respiratory changes during hip and knee replacement surgery.

METHODS

DESIGN

Prospective study, between February-May 2001.

ENVIRONMENT

Orthopedic Operative room.

PATIENTS

Twenty-one patients who underwent total hip or knee arthroplasty under general anesthesia. Patients were divided in methylmethacrylate cemented prostheses groups (CEM, n=10) and totally uncemented prostheses (NON CEM, n=11).

DATA COLLECTION

Standard anesthesia monitoring and omniplane TEE were performed. TEE probe was positioned in order to obtain "inflow-outflow" views of right heart. Measurements were obtained after anesthesia induction (T1), during femoral realing (T2) at prostheses insertion (T3), and at the end of surgery (T4).

RESULTS

Hemodynamic and respiratory parameters measured in different phases of surgical procedures were not different within groups and between groups. Fourtheen patients had TEE evidence of emboli, and the phenomenon was more evident in CEM group (Z= -347; p<0.001). During prostheses insertion, a slight, not significant increase in right ventricular dimensions was observed in both groups, without any right ventricular wall kinetic abnormality. No difference was observed between groups. No adverse cardiac or cerebrovascular events in intra- and postoperatory period were observed.

CONCLUSIONS

In normal patients total hip or knee arthroplasty is associated with embolic phenomena, without any significant change in systemic and right heart hemodynamics. Insertion of cemented prostheses does not modify hemodynamic profile. It remains to be elucidated if the occurrence of emboli has a critical role in patients with cardiorespiratory disease.