Dose Constraints and Planning Considerations for Thoracic Radiation Therapy: Delphi Consensus from a National Survey of Experts

PURPOSE/OBJECTIVE(S)

Many physicians refer to trial protocols or published guidelines (NCCN, QUANTEC, HyTEC) for dose-volume histogram (DVH) metrics. However, there may be variation in implementing these metrics during plan optimization. Some studies have suggested better outcomes for patients treated at high-volume, high-expertise centers. These differences may in part be due to greater standardization or center-specific treatment planning processes. We surveyed radiation oncologists with stated thoracic-specific expertise using the Delphi method to formulate consensus DVH metrics that would be considered ideal for high-quality radiation treatment plans.

MATERIALS/METHODS

Thoracic radiation oncology experts were identified using departmental websites of ACGME-accredited radiation oncology programs. After confirming their expertise, panelists were invited to submit their institutional templates and complete three rounds of questions related to normal organ dose constraints, target coverage metrics, prescribing practices, and other planning considerations. Queried radiation schemes included conventional fractionation, twice-daily fractionation, and stereotactic body radiation therapy (3 and 5 fractions). Preliminary consensus statements were generated using median values for DVH metrics and were iteratively refined in subsequent surveys. Consensus was pre-defined as ≥75% agreement among panelists.

RESULTS

A total of 194 experts were invited, and 100 agreed to participate. The panel was 28% female and included experts from 29 states with a median of 11 years of clinical experience (IQR 6-19). 89% specialized in 1-2 disease sites. Response rates for the Demographics, round 1, 2, and 3 surveys were 83%, 78%, 57%, and 55%, respectively. 93% of panelists believed that DVH metrics should provide thresholds for both optimal and acceptable criteria for treatment planning. 49 of the 96 proposed normal tissue dose constraint statements were iterated to consensus (Table 1), and 5 of 7 proposed target coverage metric statements achieved consensus.

CONCLUSION

This study highlights the heterogeneity in metrics used by thoracic radiation oncologists and provides levels of consensus on ideal and acceptable dose constraints as guidance for treatment planning. Future directions include using these statements to develop prescription templates and acceptance criteria for treatment planning systems for widespread use as well as extending this Delphi approach to additional disease sites.

Patterns of Locoregional Pancreatic Cancer Recurrence after Total Neoadjuvant Therapy and Implications on Optimal Neoadjuvant Radiation Treatment Volumes

PURPOSE/OBJECTIVE(S)

Neoadjuvant treatment for patients with localized pancreatic adenocarcinoma (PDAC) has improved survival duration. As survival increases, local disease control becomes even more important. We sought to understand the patterns of locoregional recurrence following total neoadjuvant therapy (TNT) and determine the impact of treatment volumes on recurrence.

MATERIALS/METHODS

Patients with PDAC managed with neoadjuvant chemotherapy and chemoradiation (TNT) followed by surgery who developed an isolated locoregional or simultaneously locoregional and distant recurrence were identified. Locoregional recurrences were individually contoured utilizing commercially available software. When available, original neoadjuvant dose distributions were registered to the scans on which the locoregional recurrences were contoured. Recurrences where then classified as in-field (> 95% of prescription dose), marginal (50-95% of prescription dose), or out of field (< 50% of prescription dose). Target volumes were created using four commonly utilized PDAC contouring guidelines to characterize the relationship of the local recurrence to the RT dose distribution.

RESULTS

Of 474 patients treated with TNT and surgery, 80 (17%) patients developed a locoregional recurrence with or without distant recurrence, visible on diagnostic imaging. Of the 80 patients, 56 (70%) had tumors in the pancreatic head; 46 (57.5%) were borderline resectable, 23 (28.8%) locally advanced, and 11 (13.6%) resectable. The most common initial neoadjuvant therapies were FOLFIRINOX (57.5%) and gemcitabine/nab-paclitaxel (18.8%). Chemoradiation included concurrent gemcitabine (47.5%) or 5-fluorouracil (26.3%). RT dose distributions were available for 38 patients; 22 (57.9%) had in-field failures, 9 (23.7%) marginal failures, and 7 (18.4%) out of field failures. Each published contouring atlas covered a relatively low percentage of recurrences, which are summarized in Table 1. Regions at particularly high likelihood of recurrence that were under covered on existing atlases included: aortic-diaphragmic junction, retro-pancreatic duodenal nodal basin, and the region to the right of the superior mesenteric artery (SMA).

CONCLUSION

We present the largest series (to our knowledge) of mapped locoregional recurrences for patients being treated with TNT in PDAC. These recurrences differ substantially from established atlases and highlight anatomical regions of highest priority for RT coverage. A novel visual contouring volume highlighting these regions will be presented which will strive to advance the use of RT in the TNT setting.

Targeting Myc-driven stress addiction in colorectal cancer

MYC is a proto-oncogene that encodes a powerful regulator of transcription and cellular programs essential for normal development, as well as the growth and survival of various types of cancer cells. MYC rearrangement and amplification is a common cause of hematologic malignancies. In epithelial cancers such as colorectal cancer, genetic alterations in MYC are rare. Activation of Wnt, ERK/MAPK, and PI3K/mTOR pathways dramatically increases Myc levels through enhanced transcription, translation, and protein stability. Elevated Myc promotes stress adaptation, metabolic reprogramming, and immune evasion to drive cancer development and therapeutic resistance through broad changes in transcriptional and translational landscapes. Despite intense interest and effort, Myc remains a difficult drug target. Deregulation of Myc and its targets has profound effects that vary depending on the type of cancer and the context. Here, we summarize recent advances in the mechanistic understanding of Myc-driven oncogenesis centered around mRNA translation and proteostress. Promising strategies and agents under development to target Myc are also discussed with a focus on colorectal cancer.

Role of biologically important imidazole moiety on the antimicrobial and anticancer activity of Fe(III) and Mn(II) complexes

Currently, most pathogens influencing a number of epidemics outline a notable warning to human health. It has pushed researchers to design new antimicrobial drugs using transition metals that are studied in proceeding fewer years for their antimicrobial properties. Henceforth, in this work, two mononuclear complexes [Imz-H][Fe(pda)₂]⋅1⋅3H₂O (1) and [Mn(Imz)₆]⋅2Cl^-⋅2H₂O (2) [Imz = imidazole and H₂pda = 2,6 pyridine dicarboxylic acid] are isolated and characterized systematically by various spectral and single-crystal XRD studies. The antimicrobial activity of the present hexadentate complexes of Fe(III) and Mn(II) against Gram-positive as well as Gram-negative bacteria is also assessed. Augmented activity against standard isolates of Staphylococcus aureus with a minimum inhibitory concentration (MIC) is observed. Similar activity was also observed toward Escherichia coli, Klebsiella pneumoniae and Listeria monocytogenes. 1 and 2 have excellent bactericidal activity, and no resistant mutant for S. aureus was seen. The compound also unveiled antibiofilm activity and was capable to disrupt significantly the pre-formed biofilms and this property was confirmed by XTT assay experiment. The MTT assay data indicate that 1 and 2 can be used as anticancer agents toward the RAW 64.7 (human macrophage/monocyte) cell line. Further, the molecular docking study reveals that the role of imidazole is very important in the biological activity of these complexes. Moreover, our results suggest that 1 and 2 with its effective anti-microbial, anti-biofilm and cytotoxicity activity can be used to treat bacterial and fungal infections and could be appraised clinically for further applications.Communicated by Ramaswamy H. Sarma.

Olax scandens Mediated Biogenic Synthesis of Ag-Cu Nanocomposites: Potential Against Inhibition of Drug-Resistant Microbes

In the present study, we have synthesized silver-copper nanocomposites (Ag-Cu NCs) using an Olax scandens leaf extract (green synthesis method) and evaluated their antimicrobial potential against less susceptible pathogens. The kinetics of Ag-Cu NCs synthesis was followed by UV-VIS and fluorescence spectroscopy. The physicochemical characterization of as-synthesized Ag-Cu NCs was executed using electron microscopy, Energy Dispersive X-Ray, Fourier Transform Infrared Spectroscopy, and a Differential Light Scattering method. As-synthesized Ag-Cu NCs induced the formation of Reactive Oxygen Species (ROS), thereby causing alteration and decrementation of cellular proteins, DNA, lipids, etc., and eventually leading to cell death, as determined by a Live/Dead assay. Next, we assessed the anti-biofilm potential of as-synthesized Ag-Cu NCs against biofilm forming bacteria. The as-synthesized Ag-Cu NCs, when compared to monometallic silver nanoparticles, exhibited significantly higher anti-microbial activity against both sensitive as well as drug resistant microbial isolates.

Cardiac glycoside digoxin ameliorates pro-inflammatory cytokines in PBMCs of rheumatoid arthritis patients in vitro

Rheumatoid arthritis (RA) is a systemic autoimmune disorder characterized by hyperplasia of the synovial membrane along with persistent inflammation of joints. Earlier studies suggest the crucial role of Th1 and Th17 subsets of T-helper cells in the pathogenesis of RA. Digoxin, a cardiac glycoside, is widely used in the treatment of heart failure. Keeping into consideration the potential of digoxin to regulate inflammatory responses in the host, we assessed its effect on the peripheral blood mononuclear cells (PBMCs) of RA patients. The PBMCs were incubated with a varying amount (10-500 nM) of digoxin for 24 h at 37 °C. There was a significant reduction in the population of Th17 cells upon treatment with digoxin. On the other hand, the digoxin treatment failed to modify the expression of T-bet and IFN-γ at both proteins as well as mRNA level in the treated PBMCs. The cardiac glycoside also inhibited transcription factor ROR-γt in the Th17 cells. We also found a decrease in the levels of IL-1β, IL-6, IL-17, and IL-23 cytokines in the culture supernatant of digoxin treated PBMCs isolated from RA patients. The data of the present study suggest the preferential role of digoxin in suppressing the differentiation of Th17 cells in RA patients.

T helper cell subpopulations repertoire in peripheral blood and its correlation with sex of newly diagnosed arthritis patients: A gender based study

Rheumatoid arthritis (RA) is an inflammatory autoimmune disorder. Autoreactive T cells play a very significant role in the pathogenesis of RA. However, the exact mechanisms of disease severity and pathogenesis are poorly understood. We attempted to correlate T-helper cell activities with sexes of newly diagnosed patients with RA. The patients were divided based on their sex and disease severity. Examination of the expression of various factors using quantitative real-time PCR and FACS analysis of peripheral blood mononuclear cells revealed that T-bet, ROR-γt, Foxp3, and the level of cytokines associated with Th1 cells were almost identical among male and female patients with RA. Interestingly, there was a high correlation between Th17 expression and disease severity in female patients with RA. In general, there was no significant correlation between Th1 cell population and the disease severity in newly diagnosed patients with RA. In contrast, the frequency of both Th17 and Treg cells was higher in patients with more severe disease. The results suggested that, in patients with RA, the T-helper cell balance within peripheral blood was skewed towards the Th17 and Treg phenotypes. Besides Th17- and Treg-associated cytokines, elevated expression of IL-27/IL-23 cytokines might also be responsible for increased disease severity in female patients with RA.

A quinoline-based fluorescent probe for selective detection and real-time monitoring of copper ions – a differential colorimetric approach

A quinoline moiety was used as a building block for designing a probe for the selective detection of copper ions in a partially aqueous medium.

Regulation of phosphorus bioavailability by iron nanoparticles in a monomictic lake

Dissolved reactive phosphorous (DRP) in lake systems is conventionally considered to predominate over other dissolved P species, however, this view neglects an important set of interactions that occurs between P and reactive iron hydroxide surfaces. This study addresses the coupling of P with dispersed iron nanoparticles in lakes, an interaction that may fundamentally alter the bioavailability of P to phytoplankton. We used diffusive gradients in thin films (DGT) and ultrafiltration to study Fe-P coupling in the water column of a monomictic lake over a hydrological year. Fe and P were predominantly colloidal (particle diameters > ~5 nm < ~20 nm) in both oxic epilimnetic and anaerobic hypolimnetic waters, but they were both DGT-labile under sub-oxic conditions, consistent with diffusion and dissolution of Fe-and-P-bearing colloids within the DGT diffusive gel. During peak stratification, increases in Fe and P bioavailability were spatially and temporally coincident with Fe nanoparticle dissolution and the formation of a deep chlorophyll maximum at 5-8 m depth. These results provide a window into the coupling and decoupling of P with mobile iron colloids, with implications for our understanding of the behaviour of nutrients and their influence on phytoplankton community dynamics.

Prevalence of healthcare-associated infection at a tertiary hospital in the Northern Cape Province, South Africa

Background: Healthcare-associated infections (HCAIs) are a well-known public health threat; however, published data on the endemic burden of HCAIs in sub-Saharan Africa are limited. This study aimed to determine the prevalence of primary bloodstream infection (PBSI), surgical site infection (SSI), lower respiratory tract infection (LRTI) and urinary tract infection (UTI) at Kimberley Hospital Complex (KHC), Northern Cape.Methods: A one-day pointprevalence survey was conducted between February 2016 and March 2016 on all patients admitted to 15 selected wards at KHC. The Standardised Centers for Disease Control and National Nosocomial Infection Surveillance Systems criteria were used.Results: A total of 326 patients were surveyed and the overall HCAI prevalence rate was 7.67%. This included 4.60% SSIs, 1.53% UTIs, 0.92% PBSIs and 0.92% LRTIs. Patients with HCAI stayed a mean of 20.8 days compared with 9.1 days for the remaining patients. Almost 75% (n = 240) of the surveyed patients had one or more recognised risk factors. The most isolated microorganism among the 11 microorganisms isolated was Klebsiella pneumoniae (36.4%). Half (54.5%) of the isolated organisms were resistant to penicillin. At the time of the survey, 42.0% of all the patients were on antimicrobials of which amoxicillin/clavulanic acid was most commonly prescribed (29.9%). Conclusion: The overall HCAI prevalence rate found in KHC is encouraging, but the prevalence of SSI is of concern. Further studies are needed to identify risk factors and target this as an area where preventative interventions can be implemented.

Application of Next Generation Sequencing for Diagnostic Testing of Tree Fruit Viruses and Viroids

Conventional detection of viruses and virus-like diseases of plants is accomplished using a combination of molecular, serological, and biological indexing. These are the primary tools used by plant virologists to monitor and ensure trees are free of known viral pathogens. The biological indexing assay, or bioassay, is considered to be the "gold standard" as it is the only method of the three that can detect new, uncharacterized, or poorly characterized viral disease agents. Unfortunately, this method is also the most labor intensive and can take up to three years to complete. Next generation sequencing (NGS) is a technology with rapidly expanding possibilities including potential applications for the detection of plant viruses. In this study, comparisons are made between tree fruit testing by conventional and NGS methods, to demonstrate the efficacy of NGS. A comparison of 178 infected trees, many infected with several viral pathogens, demonstrated that conventional and NGS were equally capable of detecting known viruses and viroids. Comparable results were obtained for 170 of 178 of the specimens. Of the remaining eight specimens, some discrepancies were observed between viruses detected by the two methods, representing less than 5% of the specimens. NGS was further demonstrated to be equal or superior for the detection of new or poorly characterized viruses when compared with a conventional bioassay. These results validated both the effectiveness of conventional virus testing methods and the use of NGS as an additional or alternative method for plant virus detection.

Feasibility of cochlear implantation in Mucopolysaccharidosis

Mucopolysaccharidoses (MPS) are a group of rare inherited metabolic disorders resulting from deficiencies of particular enzymes involved in the breakdown of glycosaminoglycans. Amongst the manifestations of MPS within the head and neck patients may develop conductive, mixed or sensorineural hearing loss.

OBJECTIVE

The main objective of this paper is to describe the management of profound sensorineural hearing loss in children with Mucopolysaccaridosis. The primary outcome measures for this case series were improvement in auditory performance and speech perception scores following cochlear implantation. Secondary outcome measures included surgical complications.

METHODS

We carried out a casenote review of the first two cases of cochlear implantation (CI) to rehabilitate profound sensory neural hearing loss in Mucopolysaccharidoses. Improvement in auditory performance was measured by categories of auditory performance (CAP) score, speech reception score (SRS) and the IHR McCormick toy discrimination test.

RESULTS

Both patients with MPS had demonstrable benefit from CI in terms of auditory performance and speech perception. The first patient improved from pre-operatively only managing to recognise environmental sounds to understanding conversation without lip-reading with a familiar talker. Following CI, the second patient can discriminate speech in noisy environments to a degree, without lip-reading. No peri-operative complications were noted in either patient.

CONCLUSION

As the medical management of the MPS has progressed there is likely to be a corresponding increase in survival. This increased life-expectancy will likely lead to greater numbers of patients with MPS surviving long enough to develop profound hearing loss. Likewise, when considering the risks and benefits of quality of life interventions such as CI in patients with MPS, it is more likely that the risks of surgery and general anaesthesia will be considered acceptable. Clinicians managing such patients will need to be aware of these developments.

Molecular epidemiology of Malassezia globosa and Malassezia restricta in Sudanese patients with pityriasis versicolor

Pityriasis versicolor is a superficial infection of the stratum corneum caused by Malassezia yeasts. The cutaneous Malassezia globosa and Malassezia restricta in Sudanese patients with pityriasis versicolor were elucidated using a molecular-based, culture-independent method and compared with that in healthy individuals. Scale samples were collected by applying an Opsite™ transparent dressing to lesional and non-lesional sites on 29 Sudanese patients with pityriasis versicolor and 54 healthy individuals. Malassezia DNA was extracted directly from the samples. The overall level of colonization by Malassezia globosa and Malassezia restricta was analyzed by real-time PCR using a TaqMan probe. The overall level of colonization by Malassezia at the lesional sites was higher than that at the non-lesional sites for all body sites, including the face, neck, cheeks, and trunk (2.7- to 6.0-fold increase). Both M. globosa and M. restricta were detected in patients and healthy individuals. However, M. globosa predominated at lesional sites, whereas the level of colonization by both species was similar in healthy individuals.

Therapeutic feeding at a rural hospital in Zimbabwe

OBJECTIVE

The purpose of this audit was to review treatment outcomes of participants in the Cooperazione e sviluppo/Cooperation and Development (CESVI), Therapeutic Feeding Programme (TFP) (i.e., death vs cure vs absconded) and to make recommendations for improving this and other similar programmes.

DESIGN

This study was a retrospective chart review. The charts of all patients admitted to the TFP from 1 January 2005 to 31 December 2005 were analyzed.

SETTING

The Salvation Army Howard Hospital is a district hospital in rural Zimbabwe. The hospital provides both inpatient and outpatient paediatric care.

SUBJECTS

132 consecutive children were enrolled in the TFP in 2005.

INTERVENTION

The objectives of the TFP included identification of children with severe malnutrition; treating complications associated with severe malnutrition and prescribing appropriate dietary treatment.

MAIN OUTCOME MEASURES

The main outcome of interest was whether TFP participants died, were cured, or absconded. We assessed factors that may be associated with these outcomes such as age, gender, comorbidities and length of stay.

RESULTS

Female children and children with marasmus were more likely to abscond from the programme than male children and children with kwashiorkor (p = 0.041, 0.039 respectively). The majority of children who died while in the programme did so within the first week of their admission. The majority of children who were cured while in the programme achieved this goal after two weeks of hospitalization (p < 0.0001).

CONCLUSION

Given the contextual factors in rural African settings that could potentially impede the healthy growth and development of children, this review has produced programmatic recommendations and suggestions for future research directions.

Insertion of the F factor into the cluster of rfa (rough A) genes of Salmonella typhimurium

From F(+) strains of Salmonella typhimurium, isolates were obtained representing two new classes of Hfr strains, HfrK1 and HfrK2, in which the insertion of the F factor into the rfa genes results in chromosome mobilization either clockwise or anticlockwise from rfa, and in the Rfa phenotype. The point of insertion of the F factor into the cluster of rfa genes, revealed by studies of the early transfer of their normal alleles, is as follows: xyl-cysE-rfa-657 (HfrK2-1, SA540 -->)-(<-- HfrK1-1, SA458)-rfaG-(<-- HfrK1-2, SA464)-pyrE-metA