Epidemiology of healthcare-associated Pseudomonas aeruginosa in intensive care units: are sink drains to blame?

BACKGROUND

Pseudomonas aeruginosa (PA) is a common cause of healthcare-associated infection (PA-HAI) in the intensive care unit (ICU).

AIM

To describe the epidemiology of PA-HAI in ICUs in Ontario, Canada, and to identify episodes of sink-to-patient PA transmission.

METHODS

This was a prospective cohort study of patients in six ICUs from 2018 to 2019, with retrieval of PA clinical isolates, and PA-screening of antimicrobial-resistant organism surveillance rectal swabs, and of sink drain, air, and faucet samples. All PA isolates underwent whole-genome sequencing. PA-HAI was defined using US National Healthcare Safety Network criteria. ICU-acquired PA was defined as PA isolated from specimens obtained ≥48 h after ICU admission in those with prior negative rectal swabs. Sink-to-patient PA transmission was defined as ICU-acquired PA with close genomic relationship to isolate(s) previously recovered from sinks in a room/bedspace occupied 3-14 days prior to collection date of the relevant patient specimen.

FINDINGS

Over ten months, 72 PA-HAIs occurred among 60/4263 admissions. The rate of PA-HAI was 2.40 per 1000 patient-ICU-days; higher in patients who were PA-colonized on admission. PA-HAI was associated with longer stay (median: 26 vs 3 days uninfected; P < 0.001) and contributed to death in 22/60 cases (36.7%). Fifty-eight admissions with ICU-acquired PA were identified, contributing 35/72 (48.6%) PA-HAIs. Four patients with five PA-HAIs (6.9%) had closely related isolates previously recovered from their room/bedspace sinks.

CONCLUSION

Nearly half of PA causing HAI appeared to be acquired in ICUs, and 7% of PA-HAIs were associated with sink-to-patient transmission. Sinks may be an under-recognized reservoir for HAIs.

Stable, chronic in-vivo recordings from a fully wireless subdural-contained 65,536-electrode brain-computer interface device

Minimally invasive, high-bandwidth brain-computer-interface (BCI) devices can revolutionize human applications. With orders-of-magnitude improvements in volumetric efficiency over other BCI technologies, we developed a 50-μm-thick, mechanically flexible micro-electrocorticography (μECoG) BCI, integrating 256×256 electrodes, signal processing, data telemetry, and wireless powering on a single complementary metal-oxide-semiconductor (CMOS) substrate containing 65,536 recording and 16,384 stimulation channels, from which we can simultaneously record up to 1024 channels at a given time. Fully implanted below the dura, our chip is wirelessly powered, communicating bi-directionally with an external relay station outside the body. We demonstrated chronic, reliable recordings for up to two weeks in pigs and up to two months in behaving non-human primates from somatosensory, motor, and visual cortices, decoding brain signals at high spatiotemporal resolution.

Pattern completion and disruption characterize contextual modulation in the visual cortex

Vision is fundamentally context-dependent, with neuronal responses influenced not just by local features but also by surrounding contextual information. In the visual cortex, studies using simple grating stimuli indicate that congruent stimuli - where the center and surround share the same orientation - are more inhibitory than when orientations are orthogonal, potentially serving redundancy reduction and predictive coding. Understanding these center-surround interactions in relation to natural image statistics is challenging due to the high dimensionality of the stimulus space, yet crucial for deciphering the neuronal code of real-world sensory processing. Utilizing large-scale recordings from mouse V1, we trained convolutional neural networks (CNNs) to predict and synthesize surround patterns that either optimally suppressed or enhanced responses to center stimuli, confirmed by in vivo experiments. Contrary to the notion that congruent stimuli are suppressive, we found that surrounds that completed patterns based on natural image statistics were facilitatory, while disruptive surrounds were suppressive. Applying our CNN image synthesis method in macaque V1, we discovered that pattern completion within the near surround occurred more frequently with excitatory than with inhibitory surrounds, suggesting that our results in mice are conserved in macaques. Further, experiments and model analyses confirmed previous studies reporting the opposite effect with grating stimuli in both species. Using the MICrONS functional connectomics dataset, we observed that neurons with similar feature selectivity formed excitatory connections regardless of their receptive field overlap, aligning with the pattern completion phenomenon observed for excitatory surrounds. Finally, our empirical results emerged in a normative model of perception implementing Bayesian inference, where neuronal responses are modulated by prior knowledge of natural scene statistics. In summary, our findings identify a novel relationship between contextual information and natural scene statistics and provide evidence for a role of contextual modulation in hierarchical inference.

NEURD: automated proofreading and feature extraction for connectomics

We are now in the era of millimeter-scale electron microscopy (EM) volumes collected at nanometer resolution (Shapson-Coe et al., 2021; Consortium et al., 2021). Dense reconstruction of cellular compartments in these EM volumes has been enabled by recent advances in Machine Learning (ML) (Lee et al., 2017; Wu et al., 2021; Lu et al., 2021; Macrina et al., 2021). Automated segmentation methods can now yield exceptionally accurate reconstructions of cells, but despite this accuracy, laborious post-hoc proofreading is still required to generate large connectomes free of merge and split errors. The elaborate 3-D meshes of neurons produced by these segmentations contain detailed morphological information, from the diameter, shape, and branching patterns of axons and dendrites, down to the fine-scale structure of dendritic spines. However, extracting information about these features can require substantial effort to piece together existing tools into custom workflows. Building on existing open-source software for mesh manipulation, here we present "NEURD", a software package that decomposes each meshed neuron into a compact and extensively-annotated graph representation. With these feature-rich graphs, we implement workflows to automate a variety of tasks that would otherwise require extensive manual effort, such as state of the art automated post-hoc proofreading of merge errors, cell classification, spine detection, axon-dendritic proximities, and computation of other features. These features enable many downstream analyses of neural morphology and connectivity, making these new massive and complex datasets more accessible to neuroscience researchers focused on a variety of scientific questions.

First-line Palliative Chemotherapy for Colorectal Cancer: a Population-based Analysis of Delivery and Outcomes in a Single-payer Health System

AIMS

Clinical practice guidelines recommend palliative chemotherapy for most patients with metastatic colorectal cancer. However, outcomes observed in the real world compared with patients enrolled in clinical trials have not been sufficiently described. The objective of this study was to evaluate the delivery and outcomes of first-line palliative chemotherapy administered to patients with colorectal cancer in routine clinical practice compared with clinical trials.

MATERIALS AND METHODS

Using linked health administrative data, we carried out a retrospective population-level cohort study on patients diagnosed with colorectal cancer in Ontario, Canada from 2010 to 2019. Patient, disease and treatment characteristics were summarised. The primary outcome was median overall survival, stratified by treatment prescribed and age. Demographics and outcomes in this real-world population were compared with those from pivotal clinical trials. A multivariable Cox regression model reporting hazard ratios and 95% confidence intervals was used to determine factors associated with survival in patients receiving systemic treatment.

RESULTS

We identified 70 987 patients with a new diagnosis of colorectal cancer, of which 4613 received first-line chemotherapy for unresectable locally advanced or metastatic disease and formed the study cohort. Fifty-eight per cent were male and the mean age was 63 years. Most had colon cancer (69%), at least one comorbidity (73%) and lived in an urban location (79%). Less than half (47%) had surgery after diagnosis. The most common regimen prescribed was folinic acid, 5-fluorouracil and irinotecan (FOLFIRI) with bevacizumab or epidermal growth factor receptor inhibitors (EGFRi; n = 2784, 60%). Among all treated patients, the median overall survival was 17.1 months, with survival difference by regimen [median overall survival 18.3 for FOLFIRI with bevacizumab or EGFRi, 19.6 for folinic acid, 5-fluorouracil and oxaliplatin (FOLFOX)/capecitabine, oxaliplatin (XELOX) with bevacizumab or EGFRi, 13.6 for FOLFIRI alone and 7.8 for 5-fluorouracil or capecitabine]. Patients aged >80 years were most likely to have received single-agent 5-fluorouracil or capecitabine, and had inferior overall survival compared with their younger counterparts. Compared with pivotal clinical trials, patients in the real world had inferior overall survival outcomes despite similar demographic characteristics (including age and sex).

CONCLUSIONS

In this real-world population-based analysis of patients receiving first-line chemotherapy for unresectable locally advanced or metastatic colorectal cancer, survival outcomes were inferior to those reported in randomised trials despite similarities in age and sex. This information can be used when counselling patients in routine practice about expected outcomes.

Multi-Modal Digital Impressions For Palatal Defects

INTRODUCTION

This in-vitro study investigated limitations of intra-oral scanners (IOS) in capturing palatal defects at decreased mouth openings. The trueness and precision of composite 3D-printed models from Cone-Beam Computed Tomography (CBCT) and IOS were measured.

METHODS

A partially dentate palatal defect model was scanned with IOS (3M™TrueDefinition) at various simulated mouth openings. Five silicone impressions were poured in gypsum. Scans were taken using 3M™TrueDefinition; Planmeca Planscan®, n=5 each. Model was scanned on two CBCT (PlanmecaProFace®; Accuitomo170®CBCT, n=5 each). Geomagic®Control2014™ was used to create composite-models merging CBCT with IOS. Thirty composite-models were 3D-printed. Trueness and precision were measured. Pearson Correlation Coefficients measured correlation between mouth opening and data capture. Data analysed using Kruskal-Wallis, Wilcoxon rank-sum, and ANOVA. Statistical significance inferred when p⟨0.05.

RESULTS

Mouth openings ⟨20mm, IOS didn't capture information of soft tissue. Increased mouth opening positively correlated with increased data capture(r=0.93, p=0.001). AccuitomoCBCT and TrueDefinition IOS composite-models had the highest (trueness) and [precision](median (IQR) 0.172 mm(0.062-0.426)); [mean [SD] 0.080 mm [0.008]]. Casts had the lowest results (median (IQR) 0.289 mm(0.119-1.565));[mean [SD] 0.338 mm [0.089]](p⟨0.001).

CONCLUSION

Mouth opening ⟨20mm resulted in insufficient data capture by IOS for clinical applications. Composite digital models showed promising trueness and precision results.

Quasiparticle Poisoning of Superconducting Qubits from Resonant Absorption of Pair-Breaking Photons

The ideal superconductor provides a pristine environment for the delicate states of a quantum computer: because there is an energy gap to excitations, there are no spurious modes with which the qubits can interact, causing irreversible decay of the quantum state. As a practical matter, however, there exists a high density of excitations out of the superconducting ground state even at ultralow temperature; these are known as quasiparticles. Observed quasiparticle densities are of order 1  μm^{-3}, tens of orders of magnitude greater than the equilibrium density expected from theory. Nonequilibrium quasiparticles extract energy from the qubit mode and can induce dephasing. Here we show that a dominant mechanism for quasiparticle poisoning is direct absorption of high-energy photons at the qubit junction. We use a Josephson junction-based photon source to controllably dose qubit circuits with millimeter-wave radiation, and we use an interferometric quantum gate sequence to reconstruct the charge parity of the qubit. We find that the structure of the qubit itself acts as a resonant antenna for millimeter-wave radiation, providing an efficient path for photons to generate quasiparticles. A deep understanding of this physics will pave the way to realization of next-generation superconducting qubits that are robust against quasiparticle poisoning.

Risk factors for inguinal hernia repair among US adults

PURPOSE

To investigate demographic, clinical, and behavioral risk factors for undergoing inguinal hernia repair within a large and ethnically diverse cohort.

METHODS

We conducted a retrospective case-control study from 2007 to 2020 on 302,532 US individuals from a large, integrated healthcare delivery system with electronic health records, who participated in a survey of determinants of health. Participants without diagnosis or procedure record of an inguinal hernia at enrollment were included. We then assessed whether demographic (age, sex, race/ethnicity), clinical, and behavioral factors (obesity status, alcohol use, cigarette smoking and physical activity) were predictors of undergoing inguinal hernia repair using survival analyses. Risk factors showing statistical significance (P < 0.05) in the univariate models were added to a multivariate model.

RESULTS

We identified 7314 patients who underwent inguinal hernia repair over the study period, with a higher incidence in men (6.31%) compared to women (0.53%). In a multivariate model, a higher incidence of inguinal hernia repair was associated with non-Hispanic white race/ethnicity, older age, male sex (aHR = 13.55 [95% confidence interval 12.70-14.50]), and more vigorous physical activity (aHR = 1.24 [0.045]), and alcohol drinker status (aHR = 1.05 [1.00-1.11]); while African-American (aHR = 0.69 [0.59-0.79]), Hispanic/Latino (aHR = 0.84 [0.75-0.91]), and Asian (aHR = 0.35 [0.31-0.39]) race/ethnicity, obesity (aHR = 0.33 [0.31-0.36]) and overweight (aHR = 0.71 [0.67-0.75]) were associated with a lower incidence. The use of cigarette was significantly associated with a higher incidence of inguinal hernia repair in women (aHR 1.23 [1.09-1.40]), but not in men (aHR 0.96 [0.91-1.02]).

CONCLUSION

Inguinal hernia repair is positively associated with non-Hispanic white race/ethnicity, older age, male sex, increased physical activity, alcohol consumption and tobacco use (only in women); while negatively associated with obesity and overweight status. Findings from this large and ethnically diverse study may support future prediction tools to identify patients at high risk of this surgery.

Diode laser targeting red-complex bacteria in periodontitis: a systematic review

OBJECTIVE

This systematic review examines the effectiveness of diode laser irradiation in reducing the levels of red complex bacteria as well as periodontal parameters of pocket depth and clinical attachment level.

MATERIALS AND METHODS

We conducted electronic searches across databases such as Scopus, Embase, Medline, and Web of Science databases in July 2022. Randomized controlled trials that evaluated the reduction of red-complex bacteria in patients with periodontitis using diode lasers were included. The primary focus was the reduction in the microbial count of red complex bacteria, whereas probing depth and attachment level were considered secondary outcomes. Articles in languages other than English were excluded. Study quality was assessed based on the Cochrane Handbook for Systematic Reviews of Interventions and the ROB2 tool.

RESULTS

After searching the databases, eight independent studies were included, with a sample size of 210 subjects. The average age group of the study population was 30-60 years, and there was a lack of consensus on the antimicrobial effect of diode lasers. Out of the eight studies, four studies reported no significant difference in the levels of red complex bacteria before and after laser application. Three studies reported significantly lower levels of red complex bacteria in the intergroup comparison. One study reported that laser had no significant effect on intergroup bacterial levels. The combination of diode laser irradiation with scaling reduced the count of red complex bacteria and improved the clinical parameters, although not significantly.

CONCLUSIONS

Based on the limited evidence available, the adjunctive use of diode laser for scaling and root planning may provide some additional benefit in terms of reduction of red complex bacterial count and clinical parameters. Further well-designed trials and the use of objective measures are necessary before outlining universal guidelines for best practice. The adjunctive use of diode laser in non-surgical periodontal therapy may provide a reduction in the red complex microbial count and improvement in clinical parameters, decreasing the need for periodontal surgery.

Long-Term Outcomes of De-Intensified Chemoradiotherapy for Human Papillomavirus-Associated Oropharyngeal Squamous Cell Carcinoma

PURPOSE/OBJECTIVE(S)

To report long-term oncologic outcomes among patients with human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) treated with definitive de-intensified chemoradiotherapy.

MATERIALS/METHODS

Major criteria for de-intensification were (1) AJCC 7th edition T0-T3, N0-N2c, M0 (AJCC 8th edition T0-T3, N0-N2, M0), (2) pathologically confirmed p16 positive, and (3) no or minimal/remote smoking history (non-mutated p53 if ≥30 pack-years). Treatment was 60 Gy intensity-modulated radiotherapy with first-choice concurrent cisplatin 30 mg/m2 once per week (alternative regimens permissible for cisplatin ineligible patients). Patients with T0-T2 N0-1 (AJCC 7th edition) were recommended 60 Gy radiation alone. Systemic therapy received included: cisplatin 30 mg/m2 (n = 122), cetuximab (n = 15), cisplatin 40 mg/m2 (n = 12), carboplatin/paclitaxel (n = 2), and radiation alone (n = 25). Kaplan Meier estimates for overall survival (OS), progression-free survival (PFS), locoregional control (LRC), and freedom from distant metastasis (FFDM) were calculated. Cox regression models were used for comparisons among subgroups.

RESULTS

A total 176 patients received de-intensified treatment (n = 153 prospective protocol, n = 23 off-protocol). Median follow-up was 52.6 months (range 5.3 - 102.0, 90.8% with minimum 2-year follow-up); 56.8% (n = 100) were never smokers and 43.2% (n = 76) former smokers; former smokers had median 9 pack-years smoking history (range 0.25 - 50) with 46% ≥10 pack-years. Outcomes were as follows: 2-year OS 99.4% and 5-year OS 91.8%; 2-year PFS 94.1% and 5-year PFS 84.3%; 2-year LRC 98.3% and 5-year LRC 95.8%; 2-year FFDM 95.8% and 5-year FFDM 93.2%. Median time to progression events were 21.1 months (range, 7.2 - 54.1) with 37.5% (6 of 16) of recurrences occurring after 24 months. Six total locoregional events occurred (five recurrences and one site of persistent disease), within the 60 Gy planning target volume. Twenty-three patients with T0-T2 N0-1 disease received radiation alone with 2-year PFS 92.9% (5-year 83.8%) and 2-year LRC 100% (5-year 95.2%). Outcomes for former smokers with ≥10 pack-years were comparable to patients with less or no smoking history (2-year PFS 94.1% vs 94.1%; 5-year PFS 90.6% vs 82.7%; HR 0.58, p = 0.38). Early results suggest similar oncologic outcomes among those treated off-protocol (median follow-up 25.6 months) with 1 of 23 patients experiencing locoregional recurrence.

CONCLUSION

Dose de-intensification of 60 Gy radiotherapy with weekly cisplatin results in favorable long-term tumor control in patients with HPV-associated OPSCC. De-intensified 60 Gy alone may be efficacious in carefully selected patients with T0-T2 N0-1 (AJCC 7th edition) disease. Inclusion of biologically favorable patients with more extensive former smoking history in de-intensification clinical trials may be warranted.

Failure Mode and Effects Analysis for Treatment Workflow of a Novel Ring Gantry Linac

PURPOSE/OBJECTIVE(S)

A new ring gantry Linac machine combined with a PET ring is available in the market. It has 3 separate centers, one for laser, one for CT imaging and a 3rd for the Linac. As a first-generation machine of its kind, the workflow heavily depends on user-input. As example, it uses two separate coordinate systems, IEC for lasers and CT localization offsets and DICOM for treatment planning. The planner must manually convert between the two systems. We hypothesize that the unique design of the machine that is heavily dependent on users' input increases the potential of failure of treatment. The present work investigates failure modes for treatment delivery using the methodology of failure modes and effects analysis (FMEA) and proposes solutions to mitigate some of the failure modes (FMs).

MATERIALS/METHODS

A group of two radiation oncologists, two radiation therapists and three medical physicists was assembled. The process map for treatment delivery on the X1 was created and FMs were identified. Members independently graded each FM on 3 parameters, likelihood of occurrence, detectability of FM and level of severity on patient treatment. A grading scale of 1-5 was used with five representing the worst outcome in each parameter. Each member also identified the origin of each FM to be human, machine or clinical process. Mitigation solutions were proposed.

RESULTS

The process map of treatment delivery on X1 consists of six major processes and 24 sub-processes. A total of 27 FMs were identified, with many 19/27 (70%) caused by human errors and 7/27 (27%) caused by machine. From all responses, we tallied a median of 11 FMs (40%) that have both S≥ 4 and O or D ≥ 4. To further focus our analysis, we looked at the highest PRN scores from each member and found 7 FMs that were common. 1 FM was in "initiation of Treatment" sub-process and 6 FMs in "Treatment delivery" sub-process. Proposed solutions to these FMs were concerned with software upgrades. Examples are, allow changes in fractionation, allow dose tracking, auto calculation of couch position for various sub processes, allow DICOM image transfer and many more. The current clinical workflow that we adopted for these FMs either puts the burden on the user to confirm/verify parameters or the use of third-party software. In addition to these high-scoring FMs, we adopted changes in clinical workflow to mitigate other FMs, most of them through third-party software.

CONCLUSION

This study confirmed that the unique design and user-dependent machine environment, human failures are high accounting for 70% of FMs in treatment delivery alone. Our current workflow of the machine depends on direct user input to calculate/confirm certain parameters or the use of third-party software, which also depends on the user for proper completion of the task. Suggested solutions also included proposed improvement to the machine's software and user interface.

An Analysis of Delays in Treatment Time for Prostate Cancer Patients in Sub-Saharan Africa

PURPOSE/OBJECTIVE(S)

Time interval from diagnosis of prostate cancer to treatment is an important predictor of survival outcomes for patients. These time intervals can be prolonged in resource-limited settings, such as those in Sub-Saharan Africa (SSA). The purpose of this project was to analyze the time interval between diagnosis and either hormonal or radiotherapy treatment for prostate cancer patients in Nigeria and Tanzania. The outcomes can inform the implementation of the recent Lancet Oncology Commission recommendations on increasing access to radiotherapy services in SSA to curb the growing cancer burden in the region.

MATERIALS/METHODS

Data were extracted from electronic patient records at the NSIA-LUTH Cancer Center (NLCC) in Lagos, Nigeria and at the Ocean Road Cancer Institute (ORCI) in Dar Es Salaam, Tanzania. Included patients were prostate cancer patients who received hypofractionated radiotherapy (HFRT) at ORCI between January 6 - June 16, 2022, and either HFRT or conventionally fractionated radiotherapy (CFRT) at NLCC between February 1 - July 27, 2022. Simple descriptive statistics were used to calculate the mean time interval between the patient's date of diagnosis of prostate cancer and the start of hormonal or radiotherapy treatment.

RESULTS

Time to hormonal therapy was collected for 23 ORCI patients and 28 NLCC patients. The mean time interval from date of diagnosis to start of hormonal therapy was 19.3 weeks for patients in Tanzania and 8.0 weeks for patients in Nigeria. Time to radiotherapy was collected for 23 ORCI patients and 50 NLCC patients. The mean time interval from date of diagnosis to start of radiotherapy was 59.13 weeks for patients in Tanzania and 48.5 weeks for patients in Nigeria.

CONCLUSION

Prostate cancer patients in Nigeria and Tanzania experience significant delay in receiving hormonal and radiotherapy treatment, especially when compared to wait times in well-resourced countries. For example, a recent assessment of U.S. patients in the National Cancer Database who were diagnosed with prostate cancer between 2004-2015 revealed that the mean interval from diagnosis to definitive therapy (either surgery or some form of radiotherapy) was 11.3 weeks - significantly less than the mean times documented in our study of SSA patients (Cone et al., 2020). Additionally, patients in Tanzania experienced longer treatment delays compared to patients in Nigeria, highlighting potential disparities in access to care between SSA countries. These prolonged delay times are likely to negatively impact survival and represent an intervention opportunity to alleviate the cancer crisis in SSA.

Surgically Targeted Radiation Therapy (STaRT) for Brain Metastases: Initial Experience from a Prospective Multi-Institutional Registry

PURPOSE/OBJECTIVE(S)

Resection and intraoperative brachytherapy for patients with large, operable brain metastasis allows for both relief of mass effect and the delivery of radiotherapy (RT) to the resection cavity with a favorable dosimetric profile. The objective of this study was to analyze early patterns-of-care and treatment-related toxicity outcomes for brain metastasis patients treated with surgically targeted radiation therapy (STaRT) using a novel brachytherapy carrier.

MATERIALS/METHODS

Patients with brain metastasis, de novo and recurrent disease, who enrolled onto a prospective multi-institutional observational study (NCT04427384) were the subject of this analysis. Patients underwent resection and immediate implantation of bioresorbable, conformable, 20 mm x 20 mm x 4 mm collagen tile brachytherapy device(s) containing four uniform-intensity Cesium-131 sources. Toxicities were categorized using the CTCAE v5.0 adverse event (AE) criteria.

RESULTS

From 10/2020 to 01/2023, 13 participating sites enrolled and treated 48 patients with 51 metastases (13 with de novo and 35 patients with recurrent brain metastases), and 3 patients had 2 lesions implanted at the same procedure. Median age was 61 years (range: 28-80), 52% were female, and the most common primary types were lung (56%) and breast (13%). The median maximum pre-operative dimension was 3.4 cm (range: 1.7-5.7) and median pre-operative tumor volume 13.7cm3 (range: 1.7-132). 64% had received prior RT with a median time from last RT to STaRT of 14.6 months range: 3.5-57.3). Median KPS at screening was 80 (range: 50-100), and remained stable at post op visit (80, range: 50-100), and at 3-months following treatment (80, range 50-100), respectively (p>0.05). The median time for implantation was 3 minutes (range: 0.4-30). At a median follow-up of 4 months (range: <1-18), no patient experienced a radiation-attributed AE, and only 1 attributable Gr >3 AE was noted (Gr 5 intracerebral hemorrhage deemed probably related to surgery and unrelated to the implanted device).

CONCLUSION

Early results from this prospective multi-center trial demonstrate the feasibility and safety of STaRT. The lack of radiation-related AE, even with short follow-up, is intriguing given the relatively large lesion size and proportion of patients treated for recurrent, previously irradiated disease. Additional follow-up will provide data on tumor control outcomes and radiation necrosis rates using this novel technique.

Can Advanced Radiotherapy Clinical Trials be Conducted in Resources Limited Countries?

PURPOSE/OBJECTIVE(S)

The Lancet Oncology Commission on Cancer in Sub-Saharan Africa (SSA) highlighted the region's increasing cancer incidence and mortality, and recommended a series of actions to address this growing crisis. One such approach recommended by the Commission to increase access to curative treatment is the use of hypofractionated radiotherapy (HFRT). Here we highlight the barriers and facilitators to launching HFRT in SSA, as identified through the HypoAfrica clinical trial.

MATERIALS/METHODS

HypoAfrica is a longitudinal multi-center clinical trial that was launched in late 2021 at three centers in Nigeria, Tanzania, and South Africa. The goal of HypoAfrica was to assess the feasibility of implementing HFRT for localized prostate cancer in SSA. To date, 155 of 182 subjects have been enrolled in this study. During the last year, a team of radiation oncology professionals from Africa, Europe, Australia, and USA met once every Saturday and reviewed the sites' data to identify the barriers to the implementation of HFRT and find solutions to overcome these challenges. With the intent to expand HFRT trials and practice to new SSA countries and radiotherapy centers, we also conducted an online survey to elucidate the readiness of radiotherapy centers across SSA to perform HFRT.

RESULTS

The major challenge identified by this team was securing high-quality data that will yield statistically significant results. Factors that contribute to quality data are: harmonization of machine and patient-specific quality assurance (QA) procedures across the centers, data quality harmonization, and challenges associated with machine maintenance. Immediate solutions implemented included introduction of low-cost QA tools for patient-specific QA measurements, ongoing training of the site's healthcare professionals, implementation of preventative maintenance for Linacs, and data centralization infrastructure. These actions have resulted in the production of a high-quality, standardized dataset. Planned longer-term solutions to HFRT challenges include implementation of ongoing training, telehealth for remote support and QA, and the creation of an Imaging and Radiation Oncology Core for Africa. The online survey indicated that 61% of respondents' institutions perform HFRT for palliative purposes, emphasizing the readiness of sites in SSA to utilize HFRT for curative purposes.

CONCLUSION

The study serves as a useful guide for increasing access to HFRT treatment in resource-limited settings and for conducting multicenter radiotherapy clinical trials.

Expanding Radiotherapy Access in Sub-Saharan Africa: An Analysis of Travel Burdens and Patient-Related Benefits of Hypofractionation

PURPOSE/OBJECTIVE(S)

The purpose of this project was to examine the travel burdens for radiotherapy patients in Nigeria, Tanzania, and South Africa, and to assess the patient-related benefits of hypofractionated radiotherapy (HFRT) for breast and prostate cancer patients in these countries. The outcomes can inform the implementation of the recent Lancet Oncology Commission recommendations on increasing the adoption of HFRT in Sub-Saharan Africa (SSA) to enhance radiotherapy access in the region.

MATERIALS/METHODS

Data were extracted from electronic patient records at the NSIA-LUTH Cancer Center (NLCC) in Lagos, Nigeria and the Inkosi Albert Luthuli Central Hospital (IALCH) in Durban, South Africa, from written records at the University of Nigeria Teaching Hospital (UNTH) Oncology Center in Enugu, Nigeria, and from phone interviews at Ocean Road Cancer Institute (ORCI) in Dar Es Salaam, Tanzania. Google Maps was used to calculate the shortest driving distance between a patient's home address and their respective radiotherapy center. QGIS was used to map the straight-line distances to each center. Descriptive statistics were used to compare transportation costs, time expenditures, and lost wages when using HFRT versus conventionally fractionated radiotherapy (CFRT) for breast and prostate cancer. All transportation- and wage-related cost data were contextualized within each country's monthly adjusted net national income (MANNI) per capita, as reported by 2020 data from the World Bank.

RESULTS

Patients in Nigeria (n = 390) traveled a median distance of 24.0 km (interquartile range (IQR) = 238.5 km) to NLCC and 86.7 km (IQR = 87.3 km) to UNTH, patients in Tanzania (n = 23) traveled a median distance of 537.0 km (IQR = 587.5 km) to ORCI, and patients in South Africa (n = 412) traveled a median distance of 18.0 km (IQR = 15.0 km) to IALCH. Estimated transportation cost savings for breast cancer patients in Lagos and Enugu were 12,895 Naira and 7,369 Naira (20% and 11% of MANNI per capita), respectively, and for prostate cancer patients were 25,329 and 14,276 Naira (38% and 22% of MANNI per capita), respectively. Prostate cancer patients in Tanzania saved a median of 137,765 Shillings (78% of MANNI per capita) in transportation costs. Significant time expenditures - a relevant consideration for patient convenience - were also saved for ORCI patients, including a median of 80.0 hours (includes travel, treatment, and wait times). Mean transportation cost savings for patients in South Africa were 4,777 Rand (72% of MANNI per capita) for breast cancer and 9,486 Rand (143% of MANNI per capita) for prostate cancer.

CONCLUSION

Cancer patients in SSA travel considerable distances to access radiotherapy services. HFRT decreases patient-related costs and time expenditures, which may increase radiotherapy access and alleviate the growing burden of cancer in the region.

Implementation Science in Radiation Oncology: Case Study for Liver SBRT

PURPOSE/OBJECTIVE(S)

The translation of research into clinical practice is challenging and implementation science is becoming as important as the trial design and development. Implementation science methodologies have been shown to reduce research-to-practice gap in other clinical settings. This is especially true for the field of Radiation Oncology where modern hypofractionated techniques, like Stereotactic Ablative Body Radiotherapy for Liver are at a high risk of over enthusiastic implementation as well as underutilization. We present the results of a multicomponent implementation methodology utilized to develop our Liver SBRT program as a model to safely translate a complex technology into clinical practice.

MATERIALS/METHODS

After review of literature and market research a setup was created with focus on machine requirements, immobilization devices, motion management techniques and QA techniques. Clinical tools in the form of checklists were developed for patient selection, simulation along with image fusion, target delineation, planning (conformity indices, dose constraint criteria) and treatment delivery. All patients were treated on Truebeam® after Bodyfix® immobilization with plastic wrap. Planning was completed on Eclipse TPS with dose constraints and conformity guidelines defined per the RTOG 1112 and TG 101. Clinical outcomes including clinical and imaging follow-up for tumor control and toxicity were recorded. For this report, all patients treated were reviewed and compared to published data to assess the success of the implementation methodology.

RESULTS

A total of 64 consecutive Patients treated with liver SBRT at Dignity Health Cancer Institute (DHCI) were eligible for the study. 58 patients treated for primary liver malignancies were included in this analysis to assess outcomes including control of disease and toxicity to compare to the published literature. Median follow up for these patients 6.5 months (4-46mnths). Median GTV volume was 38.7cc (0.1cc-2056.1 cc), median PTV volume was 159.35 cc (21.5cc-2673.5cc). Median SBRT prescription dose was 50 Gy/5 fractions (35-50 Gy). Median Liver- GTV was 1595.8 cc(770.7cc-2983.0cc). Following toxicities were noted- Grade 1- 10.3%, Grade 2 - 1.72%, Grade 3- 3.44%. No Grade 4 toxicity was noted. 1 year LC rate was 96.6%. 8.6% showed out of field liver failure and 6.9% developed distant metastasis. These results were compared to the current published literature and are shown to be comparable.

CONCLUSION

Strong and well thought out Implementation methodologies can ensure reproducing results in clinical practice, comparable to the controlled environment of trials. These are crucial in translation of clinical trials utilizing advanced technologies to promote the culture of safety in clinical practice of Radiation Oncology. Regular assessment and tracking of clinical outcomes can be used as Quality markers for directing care and reimbursements for future.

Role of pinch in Argon impurity transport in ohmic discharges of Aditya-U Tokamak

We present experimental results of the trace argon impurity puffing in the ohmic plasmas of Aditya-U tokamak performed to study the argon transport behaviour. Argon line emissions in visible and Vacuum Ultra Violet (VUV) spectral ranges arising from the plasma edge and core respectively are measured simultaneously. During the experiments, space resolved brightness profile of Ar1+ line emissions at 472.69 nm (3p44s 2P3/2-3p44p 2D3/2), 473.59 nm (3p44s 4P5/2-3p44p 4P3/2), 476.49 nm (3p44s 2P1/2-3p44p 2P3/2), 480.60 nm (3p44s 4P5/2-3p44p 4P5/2) are recorded using a high resolution visible spectrometer. Also, a VUV spectrometer has been used to simultaneously observe Ar13+ line emission at 18.79 nm (2s22p 2P3/2-2s2p2 2P3/2) and Ar14+ line emission at 22.11 nm (2s2 1S0-2s2p 1P1). The diffusivity and convective velocity of Ar are obtained by comparing the measured radial emissivity profile of Ar1+ emission and the line intensity ratio of Ar13+ and Ar14+ ions, with those simulated using the impurity transport code, STRAHL. Argon diffusivities ~ 12 m2/s and ~ 0.3 m2/s have been observed in the edge (ρ > 0.85) and core region of the Aditya-U, respectively. The diffusivity values both in the edge and core region are found to be higher than the neo-classical values suggesting that the argon impurity transport is mainly anomalous in the Aditya-U tokamak. Also, an inward pinch of ~ 10 m/s mainly driven by Ware pinch is required to match the measured and simulated data. The measured peaked profile of Ar density suggests impurity accumulation in these discharges.

Vascular Interventions in Oncology

Vascular interventions are an important and established tool in the management of the oncology patient. The goal of these procedures may be curative, palliative or adjunctive in nature. Some of the common vascular interventions used in oncology include transarterial embolisation or chemoembolisation, selective internal radiation therapy, chemosaturation, venous access lines, superior vena cava stenting and portal vein embolisation. We provide an overview of the principles, technology and approach of vascular techniques for tumour therapy in both the arterial and venous systems. Arterial interventions are currently mainly used in the management of hepatocellular carcinoma. Transarterial embolisation, chemoembolisation and selective internal radiation therapy deliver targeted catheter-delivered treatments with the aim of reducing tumour burden, controlling tumour growth or increasing survival in patients not eligible for transplantation. Chemosaturation is a regional chemotherapy technique that delivers high doses of chemotherapy directly to the liver via the hepatic artery, while reducing the risks of systemic effects. Venous interventions are more adjunctive in nature. Venous access lines are used to provide a means of delivering chemotherapy and other medications directly into the bloodstream. Superior vena cava stenting is a palliative procedure that is used to relieve symptoms of superior vena cava obstruction. Portal vein embolisation is a procedure that allows hypertrophy of a healthy portion of the liver in preparation for liver resection. Interventional radiology-led vascular interventions play an essential part of cancer management. These procedures are minimally invasive and provide a safe and effective adjunct to traditional cancer treatment methods. Appropriate work-up and discussion of each patient-specific problem in a multidisciplinary setting with interventional radiology is essential to provide optimum patient-centred care.

Better safe than so ray: national survey of radiation protection amongst interventional radiology trainees in the United Kingdom

OBJECTIVE

To establish the provision and use of radiation personal protective equipment (PPE) and dosimetry amongst UK interventional radiology (IR) trainees and highlight areas of improvement in order to enhance the radiation safety.

METHODS

A survey questionnaire was designed by members of the British Society of Interventional Radiology (BSIR) trainee committee via survey monkey and distributed to UK IR trainees via the BSIR membership mailing list, local representatives and Twitter. The survey was open from 04/01/2021 to 20/02/2021. Only IR trainees in years ST4 and above were included.

RESULTS

Of the 73 respondents, 62 qualified for analysis. Respondents (81% male) spent a median of 5.5 sessions (half day list) per week in the angiography suite and 58% (n=36) had difficulty finding appropriately sized lead aprons at least once a week. Overall 53% (n=33) had concerns about their radiation PPE. Furthermore 56% of trainees (n=35) experienced back pain among other symptoms attributed to wearing the lead aprons available to them. 77% (n=48) regularly wore lead glasses. For trainees requiring prescription glasses (n=22) overfit goggles were provided however 17 (77%) of these trainees felt the goggles compromised their ability to perform the procedure. Eye and finger dosimeters were used by 50% and 52% of respondents respectively. Compliance with body dosimetry was 99%.

CONCLUSION

Provision of radiation PPE and dose monitoring for IR trainees is suboptimal, particularly access to adequate eye protection or suitably fitting leads. Based on the findings of this survey, recommendations have been made to promote the safety and radiation awareness of IR trainees.

ADVANCES IN KNOWLEDGE

Radiation protection practices for IR trainees nationally are poor. Provision of suitable eye protection and well fitting lead body protection is low.

Evaluating the perceptions of workplace-based assessments in surgical training: a systematic review

INTRODUCTION

Workplace-based assessments (WBAs) are intended to maximise learning opportunities in surgical training. There is speculation as to whether mandatory assessments in this form contribute to a tick-box culture. The objective of this review was to investigate surgical trainees' attitudes towards WBAs.

METHODS

This systematic review of qualitative studies was performed in accordance with the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) statement. The literature was searched on the Medline®, Embase™, PubMed and Web of Science™ databases on 22 March 2022.

RESULTS

Sixteen studies were included in the review, mostly carried out on users of the Intercollegiate Surgical Curriculum Programme portfolio in the UK. Trainees felt that WBAs were educationally useful, providing opportunity for feedback, but this was overshadowed by a pressure to reach a set annual quota for WBAs and achieve high scores. Other themes included inaccurate recording of WBAs, the role of WBAs as formative or summative assessments, engagement and accessibility of trainers, and lack of time to complete WBAs.

CONCLUSIONS

Negative perceptions about WBAs were widespread among surgical trainees despite a recognition of their capacity to facilitate learning. This review supports the recent removal of the annual quota for WBAs in UK surgical training programmes.

A systematic review of the effectiveness of community-based interventions aimed at improving health literacy of parents/carers of children

AIM

The aim of this systematic review was to examine the effectiveness of community-based health literacy interventions in improving the health literacy of parents.

METHODS

A systematic review of six databases - MEDLINE, PsycINFO, CINAHL, Cochrane Library, Embase, and Education Source - was conducted to identify relevant articles. Risk of bias was assessed using version two of the Cochrane risk of bias tool for randomised controlled trials or the Cochrane collaboration risk of bias in non-randomised studies of interventions. The study findings were grouped and synthesised following the synthesis without meta-analysis framework.

RESULTS

Eleven community-based health literacy interventions for parents were identified. Study design included randomised controlled trials (n = 4), non-randomised studies with comparison group (n = 4), and non-randomised studies without a comparison group (n = 3). Interventions were delivered digitally, in person or a combination of the two. The risk of bias was high in over half the studies (n = 7). The main findings of the studies showed some potential for both in person and digital interventions to increase parental health literacy. Studies were heterogeneous preventing a meta-analysis.

CONCLUSION

Community-based, health literacy interventions have been identified as potential methods for enhancing parental health literacy. Due to the small number of included studies and their potential for bias, these results must be interpreted with caution. This study emphasises the need for additional theory and evidence-based research on the long-term effects of community interventions.

A Retrospective Service- Evaluation of Implant Success, Survival, Periimplant Health and Prosthetic Complications in a Cohort of Head and Neck Cancer Patients

OBJECTIVES

To determine the success, survival, peri-implant health and prosthetic complications in head and neck cancer patients receiving oral rehabilitation utilising dental implants between 2008 and the present day.

MATERIALS AND METHODS

Service evaluation. Survival Group: Retrospective review of records to determine implant survival and prosthetic complications. Success Group: Examination to determine implant success and health.

RESULTS

Survival Group: 260 implants in 81 individuals, median follow up 49.2 months. 89.3% implant survival at 96 months, no further failures up to 133 months. 40.9% individuals required repair or remake of prosthesis by 72 months - mostly denture re-lines. Success group: 164 implants in 48 individuals, median follow up 56 months. Peri-implant mucositis detected in 22% of fixtures (37.5% individuals); peri-implantitis in 12.8% (25% individuals); 33.3% fixtures exhibiting periimplantitis at 120 months. Previous smoking significantly associated with development of peri-implantitis (HR 2.372, p=0.032, 95CI:1.232, 93.317). Compromised survival (e.g. peri-implantitis), absolute (not in mouth) or clinical failure estimated to occur in 28.1% fixtures at 101 months, mostly due to peri-implantitis.

CONCLUSIONS

There is a large burden of ongoing care in this cohort, requiring interventions to improve peri-implant health and maintain complex prostheses. Oral rehabilitation and ongoing maintenance in this cohort is complex and multi-disciplinary.