Systematic Implementation of Effective Quality Assurance Processes for the Assessment of Radiation Target Volumes in Head and Neck Cancer

PURPOSE

Significant heterogeneity exists in clinical quality assurance (QA) practices within radiation oncology departments, with most chart rounds lacking prospective peer-reviewed contour evaluation. This has the potential to significantly affect patient outcomes, particularly for head and neck cancers (HNC) given the large variance in target volume delineation. With this understanding, we incorporated a prospective systematic peer contour-review process into our workflow for all patients with HNC. This study aims to assess the effectiveness of implementing prospective peer review into practice for our National Cancer Institute Designated Cancer Center and to report factors associated with contour modifications.

METHODS AND MATERIALS

Starting in November 2020, our department adopted a systematic QA process with real-time metrics, in which contours for all patients with HNC treated with radiation therapy were prospectively peer reviewed and graded. Contours were graded with green (unnecessary), yellow (minor), or red (major) colors based on the degree of peer-recommended modifications. Contours from November 2020 through September 2021 were included for analysis.

RESULTS

Three hundred sixty contours were included. Contour grades were made up of 89.7% green, 8.9% yellow, and 1.4% red grades. Physicians with >12 months of clinical experience were less likely to have contour changes requested than those with <12 months (8.3% vs 40.9%; P < .001). Contour grades were significantly associated with physician case load, with physicians presenting more than the median number of 50 cases having significantly less modifications requested than those presenting <50 (6.7% vs 13.3%; P = .013). Physicians working with a resident or fellow were less likely to have contour changes requested than those without a trainee (5.2% vs 12.6%; P = .039). Frequency of major modification requests significantly decreased over time after adoption of prospective peer contour review, with no red grades occurring >6 months after adoption.

CONCLUSIONS

This study highlights the importance of prospective peer contour-review implementation into systematic clinical QA processes for HNC. Physician experience proved to be the highest predictor of approved contours. A growth curve was demonstrated, with major modifications declining after prospective contour review implementation. Even within a high-volume academic practice with subspecialist attendings, >10% of patients had contour changes made as a direct result of prospective peer review.

Vaccination after developing long COVID: Impact on clinical presentation, viral persistence, and immune responses

BACKGROUND

Vaccination protects against severe COVID-19 manifestations. For those with post-COVID-19 conditions (PCC) or long COVID, the impact of COVID-19 vaccination on the evolution of symptoms, immune responses, and viral persistence is unclear.

METHODS

In this prospective observational cohort study, we evaluated the number of PCC symptoms, affected organ systems, and psychological well-being scores before and after patients with PCC received COVID-19 vaccination. We simultaneously evaluated biomarkers of systemic inflammation and levels of plasma cytokines/chemokines. We measured plasma and intracellular levels of SARS-CoV-2 antigens, and immunoreactivity to SARS-CoV-2 antigens in blood.

RESULTS

COVID-19 vaccination was associated with decreases in number of PCC symptoms (pre-vaccination: 6.56 ± 3.1 vs post-vaccination: 3.92 ± 4.02; P <0.001) and affected organ systems (pre-vaccination: 3.19 ± 1.04 vs post-vaccination: 1.89 ± 1.12; P <0.001), and increases in World Health Organization (WHO)-5 Well-Being Index Scores (pre-vaccination: 42.67 ± 22.76 vs post-vaccination: 56.15 ± 22.83; P <0.001). Patients with PCC also had significantly decreased levels of several pro-inflammatory plasma cytokines/chemokines after COVID-19 vaccination including sCD40L, GRO-⍺, macrophage inflammatory protein (MIP)-1⍺, interleukin (IL)-12p40, G-colony stimulating factor (CSF), M-CSF, IL-1β, and stem cell factor (SCF). PCC participants presented a certain level of immunoreactivity toward SARS-CoV-2, that was boosted with vaccination. SARS-CoV-2 S1 antigen persisted in the blood of PCC participants, mostly in non-classical monocytes, regardless of participants receiving vaccination.

CONCLUSIONS

Our study shows higher pro-inflammatory responses associated with PCC symptoms and brings forward a possible role for vaccination in mitigating PCC symptoms by decreasing systemic inflammation. We also observed persistence of viral products independent of vaccination that could be involved in perpetuating inflammation through non-classical monocytes.

In Silico Discovery and Investigation of Novel Small Molecules Targeting PSMA7 for the Treatment of GBM

PURPOSE/OBJECTIVE(S)

The five-year survival rate for glioblastoma (GBM; WHO grade 4) remains only 5%, even with the current standard treatment of maximal safe surgical tumor resection followed by radiation treatment (RT) and concomitant and adjuvant temozolomide (TMZ). Therefore, alternative treatment therapies, such as blood-brain barrier (BBB)-permeable small molecule drugs, are needed to significantly improve patient outcomes by addressing other critical pathways in GBM progression and overcome GBM resistance to the standard treatment. Previously, we identified and validated proteasome subunit alpha type-7 (PSMA7), a subunit of the 20S proteasome, as a druggable, therapeutically vulnerable target in GBM by in vitro and in vivo methods. In this study, we performed in silico molecular docking screenings using a small molecule library to identify BBB-permeable small molecules predicted to bind to PSMA7 and investigated their potential as novel therapeutics for the treatment of GBM.

MATERIALS/METHODS

In silico molecular docking screenings were performed using the National Cancer Institute Diversity Set VI small molecule library and the crystal structure of PSMA7 obtained from the native human 20S proteasome (RCSB PDB: 5LE5). Molecules were scored based on their predicted likelihood to bind to PSMA7. Top ranked molecules were screened using the SwissADME webtool, to select molecules predicted to be BBB-permeable and not a substrate for the permeability glycoprotein (P-gp), for testing with in vitro studies. Then, in vitro cell viability assays were used to determine IC50 values for molecules in human GBM PDX and normal human cell lines. The potential for molecules to sensitize GBM cells towards TMZ and/or RT was evaluated in vitro. In vitro proteasome activity assays were used to investigate whether molecules altered the three major protease activities performed by the proteasome.

RESULTS

Computational virtual screenings using two docking algorithms (i.e., AutoDock Vina and Glide XP) identified and ranked the top small molecules most likely to bind to PSMA7. In silico screening using the SwissADME webtool predicted 99 of these molecules to be BBB-permeable and not a substrate for the P-gp. Subsequent in vitro cell viability studies determined eight of these molecules have lower IC50 values in human GBM PDX cells compared to normal human cells. Furthermore, we examined the potential of these eight molecules to sensitize GBM cells to TMZ and/or RT in vitro. Moreover, we found that three of these molecules inhibited all three major protease activities performed by the proteasome in GBM cells.

CONCLUSION

Our study identified BBB-permeable small molecules predicted to target PSMA7 that demonstrated greater toxicity to GBM cells than normal cells and inhibited proteasome activities, suggesting a potential mechanism of action. Taken together, these small molecules are potential candidates for preclinical studies and may serve as novel targeted therapies for the treatment of GBM.

Patient-Reported Cognitive Outcomes and Survival after Stereotactic Radiosurgery for 15 or More Brain Metastases

PURPOSE/OBJECTIVE(S)

Overall survival (OS) in metastatic cancer patients has been improving with continued advancements, necessitating greater attention to treatment related toxicities. Patients with ≥ 15 brain metastases (BM) continue to be treated with whole brain radiation therapy (WBRT), despite poor neurocognitive outcomes. We analyzed our institutional experience of treating these patients with stereotactic radiosurgery (SRS), with the aim of evaluating safety, cognitive outcomes, and survival metrics.

MATERIALS/METHODS

Patients who received SRS for ≥ 15 BMs in 1-5 fractions from 2014-2022 using the previously described single isocenter multi-target technique were included. Cognitive outcomes were objectively evaluated using serial Patient-Reported Outcome Measurement Information System (PROMIS) scores. Kaplan-Meier method was used for survival analysis and log-rank test was used for intergroup comparisons.

RESULTS

A total of 118 patients underwent 124 courses of LINAC-based SRS. The mean and median number of lesions treated per patient was 24.8 and 20, respectively (range 15 - 94). Most common primary histologies were lung (47.6%), melanoma (21.0%), and breast (14.5%). The median SRS dose was 24 Gy (range 18 - 30 Gy) with 87.9% receiving 3 fraction SRS. At the time of SRS, 19.4% patients had received prior WBRT and 24.2% had received at least one prior SRS course. The rate of any grade radiation necrosis (RN) and ≥ grade 3 RN were 15.3% and 3.2% respectively. New onset seizures were seen in 2.4%, alopecia in 2.4%, and subjective cognitive decline in 4% of patients. Median follow-up by reverse Kaplan-Meier method was 17.8 months (m). Cognitive data was available for 38 patients. Mean PROMIS scores at baseline, 3m, 6m and 9m after SRS were 32.0, 31.6, 30.4 and 28.7 out of 40, respectively. When longitudinal trends were available, 25 of 31 patients had a stable or improved PROMIS score. The 12m local control was 97.6%. Cumulative incidence of distant intracranial failure was 79.2%. One year freedom from neurological death, leptomeningeal disease, and salvage WBRT were 85.6%, 87.6% and 71.7% respectively. Median OS from brain metastases diagnosis was 11.3m (95% CI 7.2m - 15.3m) overall, while it was 9.2m (6.5 - 11.8m) after excluding patients who had prior WBRT or SRS (n = 79). One-year survival was 40% from diagnosis and 38.7% from SRS. On Cox regression analysis, prior WBRT (p = 0.002), higher KPS (p = 0.050), systemic therapy after SRS (p<0.001), and controlled extracranial disease (p = 0.007) predicted for improved OS.

CONCLUSION

We present here the largest study evaluating SRS for patients with ≥ 15 BMs. We found that SRS was safe, had favorable cognitive outcomes, and comparable survival outcomes to contemporary studies evaluating WBRT in this patient population. Treatment-naïve patients had a median survival of > 6 months, long enough to benefit from cognitive sparing with SRS. Our study supports further randomized studies comparing SRS and memory avoidance WBRT approaches for patients with ≥ 15 BMs.

Vertebral Compression Fracture Post Spine Stereotactic Body Radiotherapy: The Role of Vertebral Endplate

PURPOSE/OBJECTIVE(S)

Maintaining hydrostatic pressure -via Pascal's Principle- between vertebral bodies is essential to decrease the chance of vertebral compression fracture (VCF). Vertebral endplates (EP) play an essential role in this matter through maintaining the mechanical environment as well as the proper nutrition of avascular discs. The purpose of this study is to establish the correlation of VCF with disrupted EP by tumor involvement.

MATERIALS/METHODS

A retrospective analysis of de novo spine metastases treated with stereotactic body radiotherapy (SBRT) between 2013-2019. Patients (pts) with previous surgical intervention were excluded. VCF defined as new or progression of existing loss of vertebral body height. The vertebral EP region defined in relation to the vertebral body as superior EP vs inferior EP. Kaplan-Meier curves used to analyze the variables. A multivariate proportional hazard model used to assess the risk of all covariates.

RESULTS

A total of 111 pts were treated with SBRT with a median dose of 27 Gy (10-35 Gy). Median follow-up was 18 months (1.2-107). The median age was 60 years (24-87) and 59 were males (53%) and 52 were females (47%). The median body mass index (BMI) was 27 kg/m2 (16-47). Almost 9 pts diagnosed with osteoporosis prior radiation. Twelve pts received prolonged steroids. Twenty pts received bisphosphonate and 8 pts received denosumab. The median PTV was 50cc (8-465) and median Conformity Index was 1.05 (0.42-1.4). Almost 75% of pts received >95% of the dose covering 100% of the PTV. The most common histopathologies were renal cell carcinoma (25%), lung (13%) and breast (11%). Most of the pts (77%) had SINS score of 7 or less. 48 pts (43%) had either superior or inferior EP disruption secondary to the tumor at the time of radiation. Twenty pts (18%) had both superiorly and inferiorly disrupted EP. Around 20 pts (18%) developed VCF. The median time to VCF was 5.2 months (1.1-57.4). The one-year cumulative incidence of VCF was 18%. The 1-year cumulative incidence of VCF with either superiorly and/or inferiorly disrupted EP was 29% vs 6%, p value <0.001. The 1-year cumulative incidence of VCF with both superiorly and inferiorly disrupted EP was 57% vs 7% (p value <0.001). The median time to VCF was earlier in pts with both disrupted EP (2.4 months vs 5.7 months, p value <0.05). Other risk factors like SINS score of >7 and local recurrence (LR) associated with higher risk of VCF. On multivariate analysis, LR (HR 8.2 [CI 2.4-28, p- value <0.001]), tumor disrupting the EP (HR 4.5 [CI 1.3-16, p-value<0.018]) and SINS score of seven and above (HR 1.7 [CI 1.3-2.25, p-value <0.001]) correlated with the VCF risk.

CONCLUSION

In this retrospective analysis, tumor disrupting the EP, disease recurrence and high SINS score increased the risk of VCF. Cement augmentation either prophylactically or immediately following SBRT is currently being studied in a prospective trial within our institution.

Oncogenic Activities of Tribbles1 (TRIB1) Pseudokinase Overexpressed in GBM are Mediated by Protein-Protein Interactions

PURPOSE/OBJECTIVE(S)

Glioblastoma (GBM) is the most aggressive form of glioma with a low 5-year survival rate. The current treatments are inadequate and crippled by therapy resistance. Therefore, there is an unmet need to identify druggable therapeutic targets in GBM. In this study we identified TRIB1, a Ser/Thr pseudokinase that acts as a scaffold to initiate Ubiquitin Proteasome System-mediated degradation of its substrates. We and others have found that TRIB1 activates the canonical MAPK and Akt signaling cascades. Previous reports also suggest that TRIB1 contributes to chemotherapy resistance in various cancers. Therefore, we evaluated oncogenic roles of TRIB1 in GBM cells and its contribution to therapy resistance.

MATERIALS/METHODS

Patient-centered reverse translational approach was utilized to identify novel therapeutic targets. To this end, TRIB1 was identified by statistical association (Cox regression analysis) of the patient-derived gene expression profiling data publicly available from TCGA GBM cohort. TRIB1 was functionally validated in vitro by generating stable overexpression cell lines (patient-derived) by antibiotic selection. Conditional knockdown of TRIB1 was achieved by doxycycline induction. Protein-protein interactions were evaluated by co-immunoprecipitation. Protein levels were detected by western blotting. Changes in tumor volume and overall survival (OS) were calculated.

RESULTS

The mRNA profiling of TCGA GBM cohort revealed that increased TRIB1 gene expression was associated with worse OS of GBM patients [HR = 1.3 (1.0-1.5); P = 0.019]. The same analyses in our institutional cohort revealed a similar association. Mice bearing TRIB1 transgene overexpressing tumors had the increased tumor volume and shorter OS compared to empty vector control at the end of experiment. Overexpression of TRIB1 increased the phosphorylation/activation of ERK and Akt in patient-derived primary cell lines. Akt but not ERK activation was decreased after TRIB1 knockdown. TRIB1 bound directly to ERK and Akt in these cells. TRIB1 also formed a complex with p53, COP1 and HDAC1 in patient-derived primary cell lines. This protein-protein interaction was independent of TP53 mutation status.

CONCLUSION

Our data suggest that TRIB1 overexpressed in GBM executes various oncogenic functions through interaction with different proteins. Activating ERK signaling, can induce cell proliferation. Similarly, by activating Akt it can cause prosurvival effects. Finally, by associating with HDAC1 and COP1, TRIB1 can modulate p53 function. All these protein-protein interactions ultimately contribute to chemoradiotherapy resistance in GBM cells. We are currently developing small molecule inhibitors targeting the above-mentioned interactions of TRIB1 to overcome therapeutic resistance.

Hypoxia-Inducible Transgelin-2 Confers Treatment Resistance through Activation of PI3K/Akt/GSK3β Pathway in Glioblastoma

PURPOSE/OBJECTIVE(S)

Glioblastoma (GBM) patients with wild-type IDH experience worse survival response to the standard treatment of surgery followed by radiation therapy (RT) and temozolomide (TMZ) chemotherapy compared to their mutant IDH counterparts. This treatment has remained relatively ineffective partly due to the highly invasive phenotype of GBM leading to therapeutic resistance and tumor recurrence. Hypoxia is one of the key characteristic features of GBM which results in cancer metastasis and confers treatment resistance. Therefore, it is paramount to identify targets to help overcome hypoxia-induced treatment resistance in glioblastoma. Our lab has identified transgelin-2 (TAGLN2) to be significantly upregulated in IDH-wt GBM through multiple molecular profiling studies. This study aims to understand the mechanisms by which TAGLN2 confers treatment resistance for developing additional treatments for GBM. Additionally, active drug development efforts are also underway to target TAGLN2 for circumventing these therapeutic resistance mechanisms for effective GBM therapy.

MATERIALS/METHODS

RNAi-mediated TAGLN2 knockdown (KD) approach was employed to assess the functions of TAGLN2 in GBM patient-derived xenograft (PDX) cell lines. Series of in vitro functional assays were performed to assess the role of TAGLN2 in these cell lines. Cell proliferation, invasion ± RT and/or TMZ were assessed by MTS and Trans-well invasion assays. Subsequently, WB analysis of oncogenic signaling pathways was performed following Transgelin-2 KD. Co-IP assays and Biacore/SPR analyses were performed to study the binding affinity and kinetics for the interaction of PTEN with TAGLN2. Further, cells were intracranially implanted in nude mice to assess the role of TAGLN2 on tumor growth in vivo.

RESULTS

Conditional KD of TAGLN2 reduces cell proliferation, survival and invasive potential of GBM PDX cell lines. TAGLN2 KD also improved the sensitivity of these cells to both TMZ and radiation in vitro, as assessed by proliferation, survival, clonal expansion, and invasion. Histopathological studies of human GBM tumors and mouse xenograft tumors showed elevated expression of TAGLN2 in the peri-necrotic region of the tumors indicating that TAGLN2 protein level was upregulated by hypoxia. We also show that TAGLN2 is induced in hypoxic microenvironments with GBM PDX cell lines and its overexpression may enhance cellular resistance towards conventional therapy. Subsequently, we also show that hypoxia-induced TAGLN2 activates the PI3K/Akt oncogenic pathway through binding and inhibition of PTEN. Finally, in vivo data using an orthotopic xenograft mouse model shows reduction of tumor growth with knockdown of TAGLN2.

CONCLUSION

Our in vitro and in vivo xenograft studies suggest that TAGLN2 confers treatment resistance to GBM contributing to tumor recurrence. Altogether, TAGLN2 may serve as a potential therapeutically vulnerable target in GBM specifically through its role in cell survival and invasion.

Pulse parameter optimizer: an efficient tool for achieving prescribed dose and dose rate with electron FLASH platforms

Purpose. Commercial electron FLASH platforms deliver ultra-high dose rate doses at discrete combinations of pulse parameters including pulse width (PW), pulse repetition frequency (PRF) and number of pulses (N), which dictate unique combinations of dose and dose rates. Additionally, collimation, source to surface distance, and airgaps also vary the dose per pulse (DPP). Currently, obtaining pulse parameters for the desired dose and dose rate is a cumbersome manual process involving creating, updating, and looking up values in large spreadsheets for every treatment configuration. This work presents a pulse parameter optimizer application to match intended dose and dose rate precisely and efficiently.Methods. Dose and dose rate calculation methods have been described for a commercial electron FLASH platform. A constrained optimization for the dose and dose rate cost function was modelled as a mixed integer problem in MATLAB (The MathWorks Inc., Version9.13.0 R2022b, Natick, Massachusetts). The beam and machine data required for the application were acquired using GafChromic film and alternating current current transformers (ACCTs). Variables for optimization included DPP for every collimator, PW and PRF measured using ACCT and airgap factors.Results. Using PW, PRF,Nand airgap factors as parameters, a software was created to optimize dose and dose rate, reaching the closest match if exact dose and dose rates are not achievable. Optimization took 20 s or less to converge to results. This software was validated for accuracy of dose calculation and precision in matching prescribed dose and dose rate.Conclusion. A pulse parameter optimization application was built for a commercial electron FLASH platform to increase efficiency in dose, dose rate, and pulse parameter prescription process. Automating this process reduces safety concerns associated with manual look up and calculation of these parameters, especially when many subjects at different doses and dose rates are to be safely managed.

Epidemiological and clinical characteristics of patients with monkeypox in the GeoSentinel Network: a cross-sectional study

BACKGROUND

The early epidemiology of the 2022 monkeypox epidemic in non-endemic countries differs substantially from the epidemiology previously reported from endemic countries. We aimed to describe the epidemiological and clinical characteristics among individuals with confirmed cases of monkeypox infection.

METHODS

We descriptively analysed data for patients with confirmed monkeypox who were included in the GeoSentinel global clinical-care-based surveillance system between May 1 and July 1 2022, across 71 clinical sites in 29 countries. Data collected included demographics, travel history including mass gathering attendance, smallpox vaccination history, social history, sexual history, monkeypox exposure history, medical history, clinical presentation, physical examination, testing results, treatment, and outcomes. We did descriptive analyses of epidemiology and subanalyses of patients with and without HIV, patients with CD4 counts of less than 500 cells per mm³ or 500 cells per mm³ and higher, patients with one sexual partner or ten or more sexual partners, and patients with or without a previous smallpox vaccination.

FINDINGS

226 cases were reported at 18 sites in 15 countries. Of 211 men for whom data were available, 208 (99%) were gay, bisexual, or men who have sex with men (MSM) with a median age of 37 years (range 18-68; IQR 32-43). Of 209 patients for whom HIV status was known, 92 (44%) men had HIV infection with a median CD4 count of 713 cells per mm³ (range 36-1659; IQR 500-885). Of 219 patients for whom data were available, 216 (99%) reported sexual or close intimate contact in the 21 days before symptom onset; MSM reported a median of three partners (IQR 1-8). Of 195 patients for whom data were available, 78 (40%) reported close contact with someone who had confirmed monkeypox. Overall, 30 (13%) of 226 patients were admitted to hospital; 16 (53%) of whom had severe illness, defined as hospital admission for clinical care rather than infection control. No deaths were reported. Compared with patients without HIV, patients with HIV were more likely to have diarrhoea (p=0·002), perianal rash or lesions (p=0·03), and a higher rash burden (median rash burden score 9 [IQR 6-21] for patients with HIV vs median rash burden score 6 [IQR 3-14] for patients without HIV; p<0·0001), but no differences were identified in the proportion of men who had severe illness by HIV status.

INTERPRETATION

Clinical manifestations of monkeypox infection differed by HIV status. Recommendations should be expanded to include pre-exposure monkeypox vaccination of groups at high risk of infection who plan to engage in sexual or close intimate contact.

FUNDING

US Centers for Disease Control and Prevention, International Society of Travel Medicine.

Monkeypox in Montréal: Epidemiology, Phylogenomics, and Public Health Response to a Large North American Outbreak

BACKGROUND

Monkeypox, a viral zoonotic disease, is causing a global outbreak outside of endemic areas.

OBJECTIVE

To characterize the outbreak of monkeypox in Montréal, the first large outbreak in North America.

DESIGN

Epidemiologic and laboratory surveillance data and a phylogenomic analysis were used to describe and place the outbreak in a global context.

SETTING

Montréal, Canada.

PATIENTS

Probable or confirmed cases of monkeypox.

MEASUREMENTS

Epidemiologic, clinical, and demographic data were aggregated. Whole-genome sequencing and phylogenetic analysis were performed for a set of outbreak sequences. The public health response and its evolution are described.

RESULTS

Up to 18 October 2022, a total of 402 cases of monkeypox were reported mostly among men who have sex with men (MSM), most of which were suspected to be acquired through sexual contact. All monkeypox genomes nested within the B.1 lineage. Montréal Public Health worked closely with the affected communities to control the outbreak, becoming the first jurisdiction to offer 1 dose of the Modified Vaccinia Ankara-Bavarian Nordic vaccine as preexposure prophylaxis (PrEP) to those at risk in early June 2022. Two peaks of cases were seen in early June and July (43 and 44 cases per week, respectively) followed by a decline toward near resolution of the outbreak in October. Reasons for the biphasic peak are not fully elucidated but may represent the tempo of vaccination and/or several factors related to transmission dynamics and case ascertainment.

LIMITATIONS

Clinical data are self-reported. Limited divergence among sequences limited genomic epidemiologic conclusions.

CONCLUSION

A large outbreak of monkeypox occurred in Montréal, primarily among MSM. Successful control of the outbreak rested on early and sustained engagement with the affected communities and rapid offer of PrEP vaccination to at-risk persons.

PRIMARY FUNDING SOURCE

None.

Low-Dose Whole Thorax Radiation Therapy for COVID-19 Pneumonia: Inpatient Onboarding Process for a Randomized Controlled Trial

Purpose/Objective(s)

The mortality of the SARS-CoV-2 virus (COVID-19) has been associated with a pulmonary inflammatory response resulting in hypoxemia and rapid clinical decline. Recent work has indicated a potential therapeutic window for treatment to prevent ventilator-dependence thereby reducing mortality. PREVENT is an ongoing prospective multicenter Phase II randomized controlled trial where patients hospitalized with COVID-19 pneumonia are randomized to ultra-low dose radiation therapy (RT) versus control. This study is registered at clinicaltrials.gov, NCT04466683. The following is a description of the inpatient onboarding process of the center contributing the largest number of patients to this trial.

Materials/Methods

COVID-19 hospital admissions from the previous day were attained by the clinical research manager each morning, screened for eligibility, and then sent to the designated radiation oncologist who further delineated from this list. Common exclusion criteria were: 1. Oxygen saturation > 96% on room air, 2. Age < 50, 3. > 9 days from initial COVID-19 symptomatology. From this list, HIPAA-compliant text message contact was made with infectious disease, critical care, and nursing staff with reciprocal discussion of the trial protocol and approval for consulting the patient. Subsequently, a virtual consult was made with the patient, with witnessed informed consent obtained via telephone and in person by our research associate. Patients randomized to RT were treated within 24 hours of consent. Simulation and treatment were performed on a linear accelerator with one personal protective equipment-protected therapist moving in and out of the treatment room, and a second therapist manning the console. On-site dose calculation was performed by physics, after which the radiation oncologist approved the fields prior to treatment delivery. Simulation and treatment were performed without a computer plan; therapists underwent several practice sessions prior to treating patients on trial.

Results

Between August 28, 2020 and October 6, 2020, the first 10 enrolled patients on this multicenter trial were randomized and treated at our institution; no research staff member nor radiation oncology clinical team member contracted COVID-19 while employing this protocol.

Conclusion

This represents the first published protocol to address efficient and safe recruitment of COVID-19 patients for a radiation oncology trial. Despite the procedural hurdles of conducting a trial in the midst of a pandemic, the combination of recruitment efficiency (> 2 patients/week) and safety to the research and clinical teams (no COVID-19 infections) of this protocol has allowed for the PREVENT trial to make substantial progress in meeting recruitment goals (n = 100). This onboarding process serves as a model in conducting recruitment of COVID-19 patients for clinical trials, and is worthy of emulation at additional centers.

634 Review of Nephroureteric Surgical Service in a District Urological Center

Background

New Cross hospital has been offering radical/partial nephrectomy, nephro-ureterectomy for cancer patients and simple nephrectomy for non-functioning kidney with availability of robotic system facilities since 2016.

Methodology

Retrospective analysis of data collected prospectively between January 2019 and September 2019. All patients underwent nephrectomy/nephroureterectomy and their demographic, comorbidities and surgical outcomes data analysed.

Results

7 underwent lap robotic nephroureterectomy, 27 underwent laparoscopic radical nephrectomy, 4 underwent laparoscopic simple nephrectomy, compared to total of 13 combined cases in 2018. FtM ratio- 1:1.92(13:25). Mean cohort age 64. Mean cohort BMI is 28.3. Mean pre-op HB is 132.9. Average op time for nephroureterectomy is 247 minutes, nephrectomy is 108.2 minutes. Average blood lost is 70mls, no patient of the cohort required any blood transfusion. 1 case sustained splenic laceration had surgical repair, 1 case was abandoned due to extensive bowel involvement. No cases required conversion from laparoscopic to open procedure. Post operatively, 1 patient developed VT, 1 patient had subcut haematoma, Average increase in serum creatinine is 42, and average Hb drop is 10.7. Average admission period were 3.7 days.

Conclusions

Our urological centre manage to perform more laparoscopic nephroureteric procedures as compare to previous year without much decline in terms of patient surgical outcome.

Targeted caspofungin prophylaxis for invasive aspergillosis in high-risk liver transplant recipients, a single-center experience

BACKGROUND

Invasive aspergillosis (IA) is a rare but highly lethal complication after orthotopic liver transplantation (OLT). Targeted antifungal prophylaxis has been proposed as a strategy to prevent IA among orthotopic liver transplant recipient (OLTr), but limited data are available to support its efficacy.

METHOD

We conducted a single-center, retrospective, before and after cohort study, comparing IA incidences among OLTr who did not receive antifungal prophylaxis after transplantation (cohort 1) to OLTr who received targeted antifungal prophylaxis after liver transplantation (cohort 2). Patients in cohort 2 received caspofungin prophylaxis if they presented one of the following risk factors: retransplantation, acute liver failure, dialysis, or Aspergillus colonization prior to transplantation. The primary outcome was IA at 90 days after transplantation.

RESULTS

A total of 391 OLTr were included in the study; 181 patients in the cohort 1 (no prophylaxis) and 210 patients in the cohort 2 (targeted prophylaxis). Among patients in cohort 2, 19% (40/ 210) were considered at high risk for IA and 85% (34/40) of those received caspofungin prophylaxis. The incidence of IA at 90 days was 3.3% (6/ 181) and 0.5% (1/ 210), in cohort 1 and 2, respectively (OR 0.14; 95%CI 0.01-0.83; P = .03). Ninety-day mortality was similar among the two cohorts (3.9% (7/181) and 2.4% (5/210) in cohort 1 and 2, respectively (OR 0.61; 95% 0.18-1.93; P = .40)). The 90-day mortality among the OLTs with IA was 71% (5/7).

CONCLUSION

Targeted caspofungin prophylaxis was associated with lower rate of IA.

Anisakiasis in a Canadian patient with incarcerated epigastric hernia

Anisakiasis is human zoonotic parasitic infection caused by a nematode parasite called Anisakis. This infection is usually reported in Asian countries where consumption of raw seafood is common. Very few cases have been reported in North America. We present the case of a female Canadian patient with an Anisakis larvae in an incarcerated ventral hernia. Cases of Anisakis infections are exceedingly rare in western countries, with very few previous reports describing extra-gastrointestinal cases. Diagnosis is often difficult since the symptoms of anisakiasis are not pathognomonic. As the larvae cannot survive in the body, conservative treatment might be effective in intestinal anisakiasis and surgery is usually performed when complications are encountered. Preventive measures are crucial and include educating the public about the risks of raw fish consumption and the importance of visually inspecting consumed fish and freezing it before ingestion to kill the larvae and prevent the infection.

MSR1 repeats modulate gene expression and affect risk of breast and prostate cancer

Background

MSR1 repeats are a 36-38 bp minisatellite element that have recently been implicated in the regulation of gene expression, through copy number variation (CNV).

Patients and methods

Bioinformatic and experimental methods were used to assess the distribution of MSR1 across the genome, evaluate the regulatory potential of such elements and explore the role of MSR1 elements in cancer, particularly non-familial breast cancer and prostate cancer.

Results

MSR1s are predominately located at chromosome 19 and are functionally enriched in regulatory regions of the genome, particularly regions implicated in short-range regulatory activities (H3K27ac, H3K4me1 and H3K4me3). MSR1-regulated genes were found to have specific molecular roles, such as serine-protease activity (P = 4.80 × 10-7) and ion channel activity (P = 2.7 × 10-4). The kallikrein locus was found to contain a large number of MSR1 clusters, and at least six of these showed CNV. An MSR1 cluster was identified within KLK14, with 9 and 11 copies being normal variants. A significant association with the 9-copy allele and non-familial breast cancer was found in two independent populations (P = 0.004; P = 0.03). In the white British population, the minor allele conferred an increased risk of 1.21-3.51 times for all non-familial disease, or 1.7-5.3 times in early-onset disease. The 9-copy allele was also found to be associated with increased risk of prostate cancer in an independent population (odds ratio = 1.27-1.56; P =0.009).

Conclusions

MSR1 repeats act as molecular switches that modulate gene expression. It is likely that CNV of MSR1 will affect risk of development of various forms of cancer, including that of breast and prostate. The MSR1 cluster at KLK14 represents the strongest risk factor identified to date in non-familial breast cancer and a significant risk factor for prostate cancer. Analysis of MSR1 genotype will allow development of precise stratification of disease risk and provide a novel target for therapeutic agents.

Indigenous Transmission of Mycobacterium africanum in Canada: A Case Series and Cluster Analysis

Mycobacterium africanum is an important cause of human tuberculosis and is found almost exclusively in West Africa. We identified a cluster of patients in Montreal, Canada, with M africanum disease that share identical genotypic signatures by mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) typing and a putative epidemiological link, thus providing evidence of possible local transmission of M africanum in Montreal over a 10-year period.

Abstract PD9-11: Platelet derived growth factor receptor-β signaling: A novel therapeutic target for breast cancer associated brain metastasis

PDGFRβ is a receptor tyrosine kinase found in cells of mesenchymal origin such as fibroblasts and pericytes. Activation of this receptor is dependent on paracrine ligand induction, and its preferred ligand, PDGFB, is released by neighboring epithelial and endothelial cells. While expression of both PDGFRβ and PDGFB has been noted in patient breast tumors for decades, how PDGFB-to-PDGFRβ tumor-stromal signaling mediates breast cancer initiation, progression, and metastasis remains unclear. To test this important research question, we developed a mouse model of mesenchymal-specific PDGFRβ hyper-activation. PDGFRβ mutant mammary glands exhibit increased tertiary side-branching and epithelial proliferation confirming a stromal-specific PDGFRβ effect on neighboring epithelium during normal development. To test the effect of hyper-active mesenchymal PDGFRβ on disease progression, experimental tail vein metastasis assays were performed where we observed prominent brain metastases in 50% of the PDGFRβ mutantmice (n=5/10) with no brain lesions seen in controls (n=0/19). There was no difference in the incidence of lung or liver metastases in the mutant mice suggesting a pro-metastatic function for PDGFRβ in the brain metastatic niche. To rule out dysfunction of the blood brain barrier contributing to the observed metastatic spread, we then intracranially injected mammary tumor cells, and as expected based on our metastasis assay, found that larger tumors formed in the brains of PDGFRβ mutant mice versus controls. To our knowledge, these combined findings are the first example where genetic manipulation of the stroma increases breast cancer associated brain metastases (BCBM). Given that these pre-clinical data suggest that primary breast tumors expressing high PDGFB could preferentially metastasize to the brain, we analyzed PDGFB protein expression in a tissue microarray comprised of HER2-positive and triple negative breast cancer (TNBC) primary tumors (total n=425). While high PDGFB did not correlate with site-independent metastatic recurrence, it was prognostic of brain metastasis, mirroring our mouse data. Evaluation of PDGFB in a small cohort of matched primary breast tumors with associated brain (n=5) and lung metastases (n=2) revealed intense PDGFB staining in 100% of the brain metastases, but only 50% of the lung metastases. These findings further suggest that high primary tumor PDGFBexpression defines a subset of breast cancer patients predisposed to brain metastases and that these patients may benefit from therapeutic inhibition of PDGFRβ signaling. To test this pre-clinically, we treated mice harboring intracranial tumors with the PDGFR specific inhibitor crenolanib. Excitingly, crenolanib treatment significantly inhibited the brain tumor burden in these mice. Combined, our findings to date (1) advocate that primary tumor expression of PDGFB is a novel prognostic biomarker for the development of BCBM and (2) support clinical trial evaluation of PDGFR inhibitors for the prevention and treatment of BCBM. Ongoing studies are evaluating how the PDGFRβ-expressing mesenchymal cells within the brain promote a pro-metastatic niche.

Citation Format: Sizemore GM, Hammer AM, Thies KA, Hildreth BE, Russell LO, Sizemore ST, Trimboli AJ, Kladney RD, Steck SA, Das M, Bolyard CM, Pilarski R, Schoenfield L, Otero J, Chakravarti A, Ringel M, Kaur B, Leone G, Ostrowski MC. Platelet derived growth factor receptor-β signaling: A novel therapeutic target for breast cancer associated brain metastasis [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD9-11.

Reconstitution and substrate specificity for isopentenyl pyrophosphate of the antiviral radical SAM enzyme viperin

Viperin is a radical SAM enzyme that has been shown to possess antiviral activity against a broad spectrum of viruses; however, its molecular mechanism is unknown. We report here that recombinant fungal and archaeal viperin enzymes catalyze the addition of the 5'-deoxyadenosyl radical (5'-dA^•) to the double bond of isopentenyl pyrophosphate (IPP), producing a new compound we named adenylated isopentyl pyrophosphate (AIPP). The reaction is specific for IPP, as other pyrophosphate compounds involved in the mevalonate biosynthetic pathway did not react with 5'-dA^• Enzymatic reactions employing IPP derivatives as substrates revealed that any chemical change in IPP diminishes its ability to be an effective substrate of fungal viperin. Mutational studies disclosed that the hydroxyl group on the side chain of Tyr-245 in fungal viperin is the likely source of hydrogen in the last step of the radical addition, providing mechanistic insight into the radical reaction catalyzed by fungal viperin. Structure-based molecular dynamics (MD) simulations of viperin interacting with IPP revealed a good fit of the isopentenyl motif of IPP to the active site cavity of viperin, unraveling the molecular basis of substrate specificity of viperin for IPP. Collectively, our findings indicate that IPP is an effective substrate of fungal and archaeal viperin enzymes and provide critical insights into the reaction mechanism.

Role of honey after tonsillectomy: a systematic review and meta-analysis of randomised controlled trials

BACKGROUND

Honey reduced post-tonsillectomy pain, but its effects on awakening at night, inflammation and healing of the tonsillar fossa were controversial.

OBJECTIVES

This systematic review and meta-analysis of randomised controlled trials (RCTs) evaluated the effect of oral honey on pain, consumption of painkillers, awakening at night, healing of tonsillar fossa and adverse effects in children after tonsillectomy.

METHODS

A search of MEDLINE, EMBASE, Scopus, CINAHL and Cochrane Collaboration Library databases was performed without any restriction of publication year. The end date of search was 30 June 2016. The search was supplemented by search from Google, hand search of cross-references of selected articles and reviews, and contacting the authors of different studies. The inclusion criteria were RCTs comparing the effect of honey with control on different outcomes, in children after tonsillectomy.

RESULTS

Our search generated 64 studies, and eight RCTs met our inclusion criteria. The methodological quality of RCTs was poor. Compared to control, honey significantly decreased postoperative pain from day 1 to day 7 (P = 0.05 to <0.0001); consumption of painkillers from days 1 to 5 (P = 0.03 to 0.003) and on day 10 (P = 0.002); and number of awakening at night due to pain on days 2 and 4 after tonsillectomy (P = 0.0001, 0.004). The healing of tonsillar fossa was significantly greater with honey compared to control on days 3-4 (P = 0.02) and days ≥9 (P = 0.01) after tonsillectomy. The adverse effects were not significantly different between honey and control groups. The Grading of Recommendation, Assessment, Development and Evaluation (GRADE) of the evidence for different outcomes varied from 'low' to 'very low'.

CONCLUSIONS

Honey improved pain, requirement of painkillers and awakening at night due to pain in children after tonsillectomy. There was little improvement in healing of tonsillar fossa. The GRADE of the evidence varied from 'low' to 'very low'. A good-quality, placebo-controlled RCT of different doses and durations of administration of honey is required to evaluate its clear efficacy and safety in children after tonsillectomy.

Stromal PTEN inhibits the expansion of mammary epithelial stem cells through Jagged-1

Fibroblasts within the mammary tumor microenvironment are active participants in carcinogenesis mediating both tumor initiation and progression. Our group has previously demonstrated that genetic loss of PTEN in mammary fibroblasts induces an oncogenic secretome that remodels the extracellular milieu accelerating ErbB2-driven mammary tumor progression. While these prior studies highlighted a tumor suppressive role for stromal PTEN, how the adjacent normal epithelium transforms in response to PTEN loss was not previously addressed. To identify these early events, we have evaluated both phenotypic and genetic changes within the pre-neoplastic mammary epithelium of mice with and without stromal PTEN expression. We report that fibroblast-specific PTEN deletion greatly restricts mammary ductal elongation and induces aberrant alveolar side-branching. These mice concomitantly exhibit an expansion of the mammary epithelial stem cell (MaSC) enriched basal/myoepithelial population and an increase in in vitro stem cell activity. Further analysis revealed that NOTCH signaling, specifically through NOTCH3, is diminished in these cells. Mechanistically, JAGGED-1, a transmembrane ligand for the NOTCH receptor, is downregulated in the PTEN-null fibroblasts leading to a loss in the paracrine activation of NOTCH signaling from the surrounding stroma. Reintroduction of JAGGED-1 expression within the PTEN-null fibroblasts was sufficient to abrogate the observed increase in colony forming activity implying a direct role for stromal JAGGED-1 in regulation of mammary stem cell properties. Importantly, breast cancer patients whose tumors express both low stromal JAG1 and low stromal PTEN exhibit a shorter time to recurrence than those whose tumors express low levels of either alone suggesting similar stromal signaling in advanced disease. Combined, these results unveil a novel stromal PTEN-to-JAGGED-1 axis in maintaining the mammary epithelial stem cell niche, and subsequently inhibiting breast cancer initiation and disease progression.