A Randomised Phase II Trial to Evaluate the Feasibility of Radiotherapy Dose Escalation, Facilitated by Intensity-Modulated Arc Radiotherapy Techniques, in High-Risk Neuroblastoma

BACKGROUND AND PURPOSE

For high-risk neuroblastoma, planning target volume coverage is often compromised to respect adjacent kidney tolerance. This trial investigated whether intensity-modulated arc radiotherapy techniques (IMAT) could facilitate dose escalation better than conventional techniques.

MATERIALS AND METHODS

Children with high-risk abdominal neuroblastoma referred for radiotherapy to the primary tumour site and involved regional lymph nodes were randomised to receive either standard dose (21 Gy in 14 fractions) or escalated dose (36 Gy in 24 fractions) radiotherapy. Dual planning with both a conventional anterior-posterior parallel opposed pair radiotherapy technique and an IMAT technique was performed. The quality of target volume and organ-at-risk delineation, and dosimetric plans, were externally reviewed. Dosimetric parameters were used to judge the superior technique for treatment. This feasibility trial was not powered to detect improvement in outcome with dose escalation.

RESULTS

Between 2017 and 2020, 50 patients were randomised and dual-planned. The IMAT technique was judged more favourable in 48 patients. In all patients randomised to receive 36 Gy, IMAT would have permitted delivery of the full dose (median D50% 36.0 Gy, inter-quartile range 36.0-36.1 Gy) to the target volume, whereas dose compromise would have been required with conventional planning (median D50% 35.6 Gy, inter-quartile range 28.7-35.9 Gy).

CONCLUSION

IMAT facilitates safe dose escalation to 36 Gy in patients receiving radiotherapy for neuroblastoma. The value of dose escalation is now being evaluated in a current prospective phase III randomised trial.

Fully Automated Measurement of the Insall-Salvati Ratio with Artificial Intelligence

Patella alta (PA) and patella baja (PB) affect 1-2% of the world population, but are often underreported, leading to potential complications like osteoarthritis. The Insall-Salvati ratio (ISR) is commonly used to diagnose patellar height abnormalities. Artificial intelligence (AI) keypoint models show promising accuracy in measuring and detecting these abnormalities.An AI keypoint model is developed and validated to study the Insall-Salvati ratio on a random population sample of lateral knee radiographs. A keypoint model was trained and internally validated with 689 lateral knee radiographs from five sites in a multi-hospital urban healthcare system after IRB approval. A total of 116 lateral knee radiographs from a sixth site were used for external validation. Distance error (mm), Pearson correlation, and Bland-Altman plots were used to evaluate model performance. On a random sample of 2647 different lateral knee radiographs, mean and standard deviation were used to calculate the normal distribution of ISR. A keypoint detection model had mean distance error of 2.57 ± 2.44 mm on internal validation data and 2.73 ± 2.86 mm on external validation data. Pearson correlation between labeled and predicted Insall-Salvati ratios was 0.82 [95% CI 0.76-0.86] on internal validation and 0.75 [0.66-0.82] on external validation. For the population sample of 2647 patients, there was mean ISR of 1.11 ± 0.21. Patellar height abnormalities were underreported in radiology reports from the population sample. AI keypoint models consistently measure ISR on knee radiographs. Future models can enable radiologists to study musculoskeletal measurements on larger population samples and enhance our understanding of normal and abnormal ranges.

Dual carbon isotope-based brown carbon aerosol characteristics at a high-altitude site in the northeastern Himalayas: Role of biomass burning

PM2.5 samples (n = 34) were collected from January to April 2017 over Shillong (25.7°N, 91.9°E; 1064 m amsl), a high-altitude site situated in the northeastern Himalaya. The main aim was to understand the sources, characteristics, and optical properties of local vs long-range transported carbonaceous aerosols (CA) using chemical species and dual carbon isotopes (13C and 14C). Percentage biomass burning (BB)/biogenic fraction (fbio, calculated from 14C) varied from 67 to 92 % (78 ± 7) and correlated well with primary BB tracers like f60, and K+, suggesting BB as a considerable source. Rain events are shown to reduce the fbio fraction, indicating majority of BB-derived CA are transported. Further, δ13C (-26.6 ± 0.4) variability was very low over Shillong, suggesting it's limitations in source apportionment over the study region, if used alone. Average ratio of absorption coefficient of methanol-soluble BrC (BrCMS) to water-soluble BrC (BrCWS) at 365 nm was 1.8, indicating a significant part of BrC was water-insoluble. A good positive correlation between fbio and mass absorption efficiency of BrCWS and BrCMS at 365 nm with the higher slope for BrCMS suggests BB derived water-insoluble BrC was more absorbing. Relative radiative forcing (RRF, 300 to 2500 nm) of BrCWS and BrCMS with respect to EC were 11 ± 5 % and 23 ± 16 %, respectively. Further, the RRF of BrCMS was up to 60 %, and that of BrCWS was up to 22 % with respect to EC for the samples with fbio ≥ 0.85 (i.e., dominated by BB), reflecting the importance of BB in BrC RRF estimation.

Use of Suprapubic Panniculus for Split-Thickness Skin Graft in Buried Penis Repair

Background

In the United States, acquired buried penis deformity is an increasingly more common condition. Management of the buried penis deformity is accomplished with removal of macerated skin and subcutaneous tissue from the panniculus and prepubic region, and replacement of denuded penile skin. If local tissue advancement is insufficient to cover the defect, a skin graft may be required. Though the anterior thigh is commonly used, this creates a second defect. Here we describe 2 cases of split-thickness skin grafts harvested from the panniculus to cover buried penis deformities.

Methods

Two patients with a buried penis deformity were identified. The denuded suprapubic tissue was elevated. Using inferior traction, split-thickness skin grafts were harvested and placed onto the shaft of the penis. The remaining excess tissue was resected.

Results

One patient had a fungal rash that resolved with topical treatment. The other patient had a hematoma requiring surgical evacuation. Neither patient had any other complications, and both had over 95% take of the split-thickness skin grafts.

Conclusions

These cases demonstrate the successful use of pannicular skin grafts for buried penis deformity correction. This donor site avoids creation of a second defect. As demonstrated here, the grafts are a durable option, even in the setting of local infection and hematoma.

Novel Ameloblastin Variants, Contrasting Amelogenesis Imperfecta Phenotypes

Amelogenesis imperfecta (AI) comprises a group of rare, inherited disorders with abnormal enamel formation. Ameloblastin (AMBN), the second most abundant enamel matrix protein (EMP), plays a critical role in amelogenesis. Pathogenic biallelic loss-of-function AMBN variants are known to cause recessive hypoplastic AI. A report of a family with dominant hypoplastic AI attributed to AMBN missense change p.Pro357Ser, together with data from animal models, suggests that the consequences of AMBN variants in human AI remain incompletely characterized. Here we describe 5 new pathogenic AMBN variants in 11 individuals with AI. These fall within 3 groups by phenotype. Group 1, consisting of 6 families biallelic for combinations of 4 different variants, have yellow hypoplastic AI with poor-quality enamel, consistent with previous reports. Group 2, with 2 families, appears monoallelic for a variant shared with group 1 and has hypomaturation AI of near-normal enamel volume with pitting. Group 3 includes 3 families, all monoallelic for a fifth variant, which are affected by white hypoplastic AI with a thin intact enamel layer. Three variants, c.209C>G; p.(Ser70*) (groups 1 and 2), c.295T>C; p.(Tyr99His) (group 1), and c.76G>A; p.(Ala26Thr) (group 3) were identified in multiple families. Long-read AMBN locus sequencing revealed these variants are on the same conserved haplotype, implying they originate from a common ancestor. Data presented therefore provide further support for possible dominant as well as recessive inheritance for AMBN-related AI and for multiple contrasting phenotypes. In conclusion, our findings suggest pathogenic AMBN variants have a more complex impact on human AI than previously reported.

Evaluation of European-based polygenic risk score for breast cancer in Ashkenazi Jewish women in Israel

BACKGROUND

Polygenic risk score (PRS), calculated based on genome-wide association studies (GWASs), can improve breast cancer (BC) risk assessment. To date, most BC GWASs have been performed in individuals of European (EUR) ancestry, and the generalisation of EUR-based PRS to other populations is a major challenge. In this study, we examined the performance of EUR-based BC PRS models in Ashkenazi Jewish (AJ) women.

METHODS

We generated PRSs based on data on EUR women from the Breast Cancer Association Consortium (BCAC). We tested the performance of the PRSs in a cohort of 2161 AJ women from Israel (1437 cases and 724 controls) from BCAC (BCAC cohort from Israel (BCAC-IL)). In addition, we tested the performance of these EUR-based BC PRSs, as well as the established 313-SNP EUR BC PRS, in an independent cohort of 181 AJ women from Hadassah Medical Center (HMC) in Israel.

RESULTS

In the BCAC-IL cohort, the highest OR per 1 SD was 1.56 (±0.09). The OR for AJ women at the top 10% of the PRS distribution compared with the middle quintile was 2.10 (±0.24). In the HMC cohort, the OR per 1 SD of the EUR-based PRS that performed best in the BCAC-IL cohort was 1.58±0.27. The OR per 1 SD of the commonly used 313-SNP BC PRS was 1.64 (±0.28).

CONCLUSIONS

Extant EUR GWAS data can be used for generating PRSs that identify AJ women with markedly elevated risk of BC and therefore hold promise for improving BC risk assessment in AJ women.

The impact of electronic pathways and digital systems on neck of femur fracture outcomes globally: a systematic review

INTRODUCTION

Electronic pathways (e-pathways) and digital systems are novel interventions with several uses in healthcare, ranging from clinical decision support systems to checklists for care delivery. Their application in the management of neck of femur (NOF) fractures is evolving and they may play a key role in facilitating improvements in care delivery. The primary aim of this review was to outline the impact of e-pathways/digital systems on NOF fracture outcomes.

METHODS

A systematic literature search was performed using the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. A total of 698 citations were evaluated, of which 38 passed the inclusion/exclusion criteria. Six studies were then finalised following full-text review. Heterogenous data meant a narrative synthesis was undertaken. Risk of bias for each paper was assessed using the Downs and Black scale.

RESULTS

A statistically significant improvement was demonstrated for time to theatre (3/6 studies), length of hospital stay (2/6 studies) and secondary fracture prevention (2/6 studies). Although postoperative delirium and mortality improved with the introduction of e-pathways/digital systems, statistical significance was not achieved. No outcome measures were adversely affected.

CONCLUSIONS

This systematic review of the literature demonstrates that e-pathways and digital systems are promising novel interventions, displaying a significant positive impact on several NOF fracture outcomes. Owing to the novel nature of e-pathways and digital systems in orthopaedics, a limited number of studies were identified for review, each with variable study design. More high quality homogenous prospective cohort studies with a standardised primary outcome measure are required for more definitive conclusions of efficacy to be drawn.

CT vs. MRI: Which is More Accurate in Grading Rectal Wall Infiltration after Hydrogel Spacer Placement for Prostate Cancer Patients?

PURPOSE/OBJECTIVE(S)

The purpose of this study was to evaluate the incidence and severity of rectal wall infiltration (RWI) in prostate cancer patients after rectal hydrogel spacer implantation, a commonly used procedure to minimize rectal radiation exposure during prostate radiotherapy. The study aimed to determine correlation of RWI using computed tomography (CT) scans and magnetic resonance imaging (MRI) scans in order to determine the optimal post-placement imaging modality.

MATERIALS/METHODS

This retrospective study was conducted on 370 patients diagnosed with localized prostate cancer who underwent rectal hydrogel spacer placement from 2020 to 2022. CT scans were performed on all patients, with a smaller subset also undergoing MRI scans. The images were independently evaluated by three radiation oncologists to grade RWI levels using a standardized scoring system based on CT and MRI images after hydrogel placement. The levels were categorized as 0 (no RWI), 1 (focal RWI), 2 (moderate RWI), and 3 (significant RWI).

RESULTS

Any grade of RWI was identified in 79.8% of men with the majority (41%) being RWI grade 1. The median time for CT scans was 9 days after hydrogel spacer placement and 14.5 days for MRI scans. For the subset of patients with both CT and MRI scans after spacer (mostly SpaceOAR Vue), RWI was detected in 58.33% of patients based on CT and 61.11% of patients based on MRI. Table 1 shows the mean percentage of patients with each score of RWI for each imaging modality. MRI was more likely to lead to a designation of RWI of any grade compared to CT and more often led to detection of RWI grades 2-3.

CONCLUSION

Our findings demonstrate that the incidence and severity of RWI may be higher than previously reported in clinical trials and that MRI may be a more sensitive imaging modality. Caution is needed in the utilization of rectal spacer gels given the potential for complications with misplacement prior to radiation therapy. Further study is warranted to determine the potential impact of low-grade RWI on the safety of subsequent treatment.

Enhancement and Implementation of a Health Information Technology Module to Improve the Discrete Capture of Cancer Staging in a Diverse Regional Health System

PURPOSE

Cancer staging is the foundation for all cancer management decisions. For real-time use, stage must be embedded in the electronic health record as a discrete data element. The objectives of this quality improvement (QI) initiative were to (1) identify barriers to utilization of an existing discrete cancer staging module, (2) identify health information technology (HIT) solutions to support discrete capture of cancer staging data, and (3) increase capture across the oncology enterprise in our diverse health system.

METHODS

Six sigma QI methodologies were used to define barriers and solutions to improve discrete cancer staging. Design thinking principles informed solution development to test prototypes. Two multidisciplinary teams of disease-specific clinicians within GI and genitourinary conducted phased testing pilots to determine health system solutions. Solutions were expanded to all oncology specialties across our health system.

RESULTS

Baseline average discrete staging capture across our health system was 31%. Poor workflow efficiency, limited accountability, and technical design gaps were key barriers to timely, complete staging. Implementation of more than 25 design enhancements to a HIT solution and passive user alerts led to a postimplementation capture rate of 58% across 55 outpatient clinics involving more than 400 clinicians.

CONCLUSION

We identified key barriers to discrete data capture and designed solutions through iterative use of QI methodologies and disease-specific pilots. After implementation, discrete capture of cancer staging nearly doubled across our diverse health system. This approach is scalable and transferable to other initiatives to develop and implement clinically relevant HIT solutions across a diverse health system.

Circulating tumor DNA association with residual cancer burden after neoadjuvant chemotherapy in triple-negative breast cancer in TBCRC 030

BACKGROUND

We aimed to examine circulating tumor DNA (ctDNA) and its association with residual cancer burden (RCB) using an ultrasensitive assay in patients with triple-negative breast cancer (TNBC) receiving neoadjuvant chemotherapy.

PATIENTS AND METHODS

We identified responders (RCB 0/1) and matched non-responders (RCB 2/3) from the phase II TBCRC 030 prospective study of neoadjuvant paclitaxel versus cisplatin in TNBC. We collected plasma samples at baseline, 3 weeks and 12 weeks (end of therapy). We created personalized ctDNA assays utilizing MAESTRO mutation enrichment sequencing. We explored associations between ctDNA and RCB status and disease recurrence.

RESULTS

Of 139 patients, 68 had complete samples and no additional neoadjuvant chemotherapy. Twenty-two were responders and 19 of those had sufficient tissue for whole-genome sequencing. We identified an additional 19 non-responders for a matched case-control analysis of 38 patients using a MAESTRO ctDNA assay tracking 319-1000 variants (median 1000 variants) to 114 plasma samples from 3 timepoints. Overall, ctDNA positivity was 100% at baseline, 79% at week 3 and 55% at week 12. Median tumor fraction (TFx) was 3.7 × 10-4 (range 7.9 × 10-7-4.9 × 10-1). TFx decreased 285-fold from baseline to week 3 in responders and 24-fold in non-responders. Week 12 ctDNA clearance correlated with RCB: clearance was observed in 10 of 11 patients with RCB 0, 3 of 8 with RCB 1, 4 of 15 with RCB 2 and 0 of 4 with RCB 3. Among six patients with known recurrence, five had persistent ctDNA at week 12.

CONCLUSIONS

Neoadjuvant chemotherapy for TNBC reduced ctDNA TFx by 285-fold in responders and 24-fold in non-responders. In 58% (22/38) of patients, ctDNA TFx dropped below the detection level of a commercially available test, emphasizing the need for sensitive tests. Additional studies will determine whether ctDNA-guided approaches can improve outcomes.

mTOR-dependent loss of PON1 secretion and antiphospholipid autoantibody production underlie autoimmunity-mediated cirrhosis in transaldolase deficiency

Transaldolase deficiency predisposes to chronic liver disease progressing from cirrhosis to hepatocellular carcinoma (HCC). Transition from cirrhosis to hepatocarcinogenesis depends on mitochondrial oxidative stress, as controlled by cytosolic aldose metabolism through the pentose phosphate pathway (PPP). Progression to HCC is critically dependent on NADPH depletion and polyol buildup by aldose reductase (AR), while this enzyme protects from carbon trapping in the PPP and growth restriction in TAL deficiency. Although AR inactivation blocked susceptibility to hepatocarcinogenesis, it enhanced growth restriction, carbon trapping in the non-oxidative branch of the PPP and failed to reverse the depletion of glucose 6-phosphate (G6P) and liver cirrhosis. Here, we show that inactivation of the TAL-AR axis results in metabolic stress characterized by reduced mitophagy, enhanced overall autophagy, activation of the mechanistic target of rapamycin (mTOR), diminished glycosylation and secretion of paraoxonase 1 (PON1), production of antiphospholipid autoantibodies (aPL), loss of CD161+ NK cells, and expansion of CD38+ Ito cells, which are responsive to treatment with rapamycin in vivo. The present study thus identifies glycosylation and secretion of PON1 and aPL production as mTOR-dependent regulatory checkpoints of autoimmunity underlying liver cirrhosis in TAL deficiency.

Glutaredoxin proteins from E. coli isoforms were compared in terms of energy frustration

Glutaredoxin (GRXs) protein plays a vital role inside the cell, including redox control of transcription to the cell's antioxidant defense, apoptosis, and cellular differentiation regulation. In this study, we have investigated the energy landscape and characterized the pattern of local frustration in different forms and states of the GRX protein ofE. coli.Analysis was done on the conformational alterations, significant changes in the frustration pattern, and different GRXs such as GRX-II, GRX-III, GRX-II-GSH, and GRX-III-GSH complex. We have found the practice of frustration, and structure was quite similar in the same isoform having different states of protein; however, a significant difference was observed between different isoforms. Moreover, oxidation of GRX-I introduced an extra α-helix increasing the destabilizing interactions within the protein. The study of frustrated contacts on oxidized and reduced GRX and with bound and unbound Glutathione indicates its potential application in activating and regulating the behavior of GRXs.

Nutritional considerations for a new era: A CF foundation position paper

OBJECTIVE

To provide interim advice and considerations to the CF Community around CF nutrition in the current era.

METHODS

The Cystic Fibrosis (CF) Foundation organized a multidisciplinary committee to develop a Nutrition Position Paper based on the rapidly changing nutrition landscape in CF, due in part to widespread use of cystic fibrosis transmembrane regulator highly effective modulator therapy (HEMT). Four workgroups were formed: Weight Management, Eating Behavior/Food Insecurity, Salt Homeostasis and Pancreatic Enzyme use. Each workgroup conducted their own focused review of the literature.

RESULTS

The committee summarized current understanding of issues pertaining to the four workgroup topics and provided 6 key take-aways around CF Nutrition in the new era.

CONCLUSION

People with CF (pwCF) are living longer, particularly with the advent of HEMT. The traditional high fat, high calorie CF diet may have negative nutritional and cardiovascular consequences as pwCF age. Individuals with CF may have poor diet quality, food insecurity, distorted body image, and an higher incidence of eating disorders. An increase in overweight and obesity may lead to new considerations for nutritional management, given potential effects of overnutrition on pulmonary and cardiometabolic parameters.

ENIGMA CHEK2gether Project: A Comprehensive Study Identifies Functionally Impaired CHEK2 Germline Missense Variants Associated with Increased Breast Cancer Risk

PURPOSE

Germline pathogenic variants in CHEK2 confer moderately elevated breast cancer risk (odds ratio, OR ∼ 2.5), qualifying carriers for enhanced breast cancer screening. Besides pathogenic variants, dozens of missense CHEK2 variants of uncertain significance (VUS) have been identified, hampering the clinical utility of germline genetic testing (GGT).

EXPERIMENTAL DESIGN

We collected 460 CHEK2 missense VUS identified by the ENIGMA consortium in 15 countries. Their functional characterization was performed using CHEK2-complementation assays quantifying KAP1 phosphorylation and CHK2 autophosphorylation in human RPE1-CHEK2-knockout cells. Concordant results in both functional assays were used to categorize CHEK2 VUS from 12 ENIGMA case-control datasets, including 73,048 female patients with breast cancer and 88,658 ethnicity-matched controls.

RESULTS

A total of 430/460 VUS were successfully analyzed, of which 340 (79.1%) were concordant in both functional assays and categorized as functionally impaired (N = 102), functionally intermediate (N = 12), or functionally wild-type (WT)-like (N = 226). We then examined their association with breast cancer risk in the case-control analysis. The OR and 95% CI (confidence intervals) for carriers of functionally impaired, intermediate, and WT-like variants were 2.83 (95% CI, 2.35-3.41), 1.57 (95% CI, 1.41-1.75), and 1.19 (95% CI, 1.08-1.31), respectively. The meta-analysis of population-specific datasets showed similar results.

CONCLUSIONS

We determined the functional consequences for the majority of CHEK2 missense VUS found in patients with breast cancer (3,660/4,436; 82.5%). Carriers of functionally impaired missense variants accounted for 0.5% of patients with breast cancer and were associated with a moderate risk similar to that of truncating CHEK2 variants. In contrast, 2.2% of all patients with breast cancer carried functionally wild-type/intermediate missense variants with no clinically relevant breast cancer risk in heterozygous carriers.

Evaluation of the impact of continuous Kangaroo Mother Care (KMC) initiated immediately after birth compared to KMC initiated after stabilization in newborns with birth weight 1.0 to < 1.8 kg on neurodevelopmental outcomes: Protocol for a follow-up study

BACKGROUND

Preterm birth or low birth weight is the single largest cause of death in newborns, however this mortality can be reduced through newborn care interventions, including Kangaroo Mother Care (KMC). Previously, a multi-country randomized controlled trial, coordinated by the World Health Organization (WHO), reported a significant survival advantage with initiation of continuous KMC immediately after birth compared with initiation of continuous KMC a few days after birth when the baby is considered clinically stable. Whether the survival advantage would lead to higher rates of neurodevelopmental morbidities, or the immediate KMC will also have a beneficial effect on cognitive development also, has not been investigated. We therefore propose to test the hypothesis that low-birth-weight infants exposed to immediate KMC will have lower rates of neurodevelopmental impairment in comparison to traditional KMC-treated infants, by prospectively following up infants already enrolled in the immediate KMC trial for the first 2 years of life, and assessing their growth and neurodevelopment.

METHODS

This prospective cohort study will enroll surviving neonates from the main WHO immediate KMC trial. The main trial as well as this follow-up study are being conducted in five low- and middle-income countries in South Asia and sub-Saharan Africa. The estimated sample size for comparison of the risk of neurodevelopmental impairment is a total of 2200 children. The primary outcome will include rates of cerebral palsy, hearing impairment, vision impairment, mental and motor development, and epilepsy and will be assessed by the age of 3 years. The analysis will be by intention to treat.

DISCUSSION

Immediate KMC can potentially reduce low-birth-weight-associated complications such as respiratory disease, hypothermia, hypoglycemia, and infection that can result in impaired neurocognitive development. Neuroprotection may also be mediated by improved physiological stabilization that may lead to better maturation of neural pathways, reduced risk of hypoxia, positive parental impact, improved sleep cycles, and improved stress responses. The present study will help in evaluating the overall impact of KMC by investigating the long-term effect on neurodevelopmental impairment in the survivors.

TRIAL REGISTRATION

Clinical Trials Registry-India CTRI/2019/11/021899. Registered on 06 November 2019. Trials registration of parent trial: ACTRN12618001880235; Clinical Trials Registry-India: CTRI/2018/08/015369.

Closed-loop optogenetic control of the dynamics of neural activity in non-human primates

Electrical neurostimulation is effective in the treatment of neurological disorders, but associated recording artefacts generally limit its applications to open-loop stimuli. Real-time and continuous closed-loop control of brain activity can, however, be achieved by pairing concurrent electrical recordings and optogenetics. Here we show that closed-loop optogenetic stimulation with excitatory opsins enables the precise manipulation of neural dynamics in brain slices from transgenic mice and in anaesthetized non-human primates. The approach generates oscillations in quiescent tissue, enhances or suppresses endogenous patterns in active tissue and modulates seizure-like bursts elicited by the convulsant 4-aminopyridine. A nonlinear model of the phase-dependent effects of optical stimulation reproduced the modulation of cycles of local-field potentials associated with seizure oscillations, as evidenced by the systematic changes in the variability and entropy of the phase-space trajectories of seizures, which correlated with changes in their duration and intensity. We also show that closed-loop optogenetic neurostimulation could be delivered using intracortical optrodes incorporating light-emitting diodes. Closed-loop optogenetic approaches may be translatable to therapeutic applications in humans.

Characterization of paddy-residue burning derived carbonaceous aerosols using dual carbon isotopes

A large scale paddy-residue burning (PRB) happens every year in the northwest Indo-Gangetic Plain (IGP) during the post-monsoon season, and winds transport pollutants from the source region up to the northern Indian Ocean affecting air quality of the IGP and marine region. In this study, day-night pairs of fine aerosol samples (n = 69) were collected during October-November over Patiala (30.2°N, 76.3°E, 250 m amsl), a site located in the source region of PRB. Carbonaceous aerosols (CA) were characterised using chemical species and dual carbon isotopes (¹³C and ¹⁴C) to estimate bio vs non-bio contributions and understand their characteristics. Percentage of bio fraction (f_bio, estimated using ¹⁴C) in CA varied from 74 % to 87 % (avg: 80 ± 3) during days and 71 % to 96 % (avg: 85 ± 7 %) during nights. Further, the f_bio was found to be better correlated with aerosol mass spectrometer derived f60 compare to levoglucosan (LG) or nssK⁺, suggesting f60 a useful proxy for PRB. The δ¹³C varied from -27.7 ‰ to -26.0 ‰ (avg: -27.0 ± 0.4 ‰) and - 28.7 ‰ to -26.4 ‰ (avg: -27.5 ± 0.7 ‰) during day and night, respectively. Measured δ¹³C of the samples was found to be more enriched than expected by 0.3 to 2.0 ‰, indicating the presence of aged CA also in Patiala even during PRB period. From f_bio versus δ¹³C correlation, and from Miller-Trans plot, δ¹³C of PRB is found to be -28.9 ± 1.1 ‰, which also infers that Miller-Trans plot can be used to understand source isotopic signature in the absence of radiocarbon measurements in aerosols. Further, the characteristics ratios of organic carbon (OC) to elemental carbon (EC) (11.9 ± 4.1), LG to potassium (K⁺) (0.84 ± 0.15), OC/LG (19.7 ± 2.0) and K⁺/EC (0.75 ± 0.27) were calculated by considering samples with f_bio higher than 0.90, which can be used for source apportionment studies. Such studies are crucial in assessing the effects of PRB on regional air quality and climate.

A213 UNDERSTANDING PATIENT AND PHYSICIAN ATTITUDES AND EXPECTATIONS REGARDING IDENTIFYING AND MANAGING ANXIETY AND DEPRESSION IN IBD

Background

Patients living with Inflammatory Bowel Disease (IBD) commonly experience a number of mental health-related challenges, specifically anxiety and mood disorders (AMDs). Although there has been an awareness of the relationship between IBD and AMD within the GI research and clinical space; detection, treatment, and management amongst care providers is limited. Therefore, we are seeking to explore the overall experiences of patients living with Inflammatory Bowel Disease to identify and evaluate their experiences in interactions with GI clinicians around mental health in diverse care settings in order to determine how to best support mental health care amongst IBD patients.

Purpose

We aimed to explore perspectives, experiences and barriers to engaging with mental health-related challenges amongst IBD patients when interacting with gastroenterologists over the course of their health journey.

Method

We conducted 5 semi-structured online focus groups co-facilitated by patient researchers in early 2020 through Zoom which spanned for a total of 2.5 hours each. Participants were recruited through social media channels, GI clinics, the IMAGINE-SPOR unit, and Crohn’s and Colitis Canada. A semi-structured interview guide was developed for patient researchers to follow during the focus groups which provided guided questions that would allow patient participants to explore and reflect on: their experiences living with IBD, their expectations around mental health support, their perception of the engagement of GIs in mental health discussions, and their expectations for mental health support and services moving forward. Audio recordings from the semi-structured focus groups were then transcribed and thematic analysis was used to identify emerging themes and patient expectations.

Result(s)

We identified the following key themes: 1) experiences with IBD: difficulties related to reintegrating into social settings, feelings of loneliness; 2) expectations around mental health support: the need to develop their own resiliency strategies due to the lack of structural resources regarding mental health and IBD in the clinical space; 3) GI engagement: HCPs were dismissive of mental health symptoms, often gaslighting patients when mentioning mental health concerns during clinical encounters; and 4) expectations: a need to standardize mental health care across IBD care practice with a focus on potentially integrating healthcare providers of diverse care settings to help address the need for mental health support in such a vast patient population.

Conclusion(s)

Our study suggests that effective detection, management and awareness, along with the integration of feedback from patient lived experiences can help inform the development of mental health support and services which cater to the needs of people living with IBD. Results from this study will be interpreted in line with insight gathered from upcoming interviews of gastroenterologists and HCPs.

Please acknowledge all funding agencies by checking the applicable boxes below

CIHR, Other

Please indicate your source of funding;

IMAGINE SPOR INCUBATOR Grant

Disclosure of Interest

None Declared

Development and validation of a risk score (Delay-7) to predict the occurrence of a treatment delay following cycle 1 chemotherapy

BACKGROUND

The risk of toxicity-related dose delays, with cancer treatment, should be included as part of pretreatment education and be considered by clinicians upon prescribing chemotherapy. An objective measure of individual risk could influence clinical decisions, such as escalation of standard supportive care and stratification of some patients, to receive proactive toxicity monitoring.

PATIENTS AND METHODS

We developed a logistic regression prediction model (Delay-7) to assess the overall risk of a chemotherapy dose delay of 7 days for patients receiving first-line treatments for breast, colorectal and diffuse large B-cell lymphoma. Delay-7 included hospital treated, age at the start of chemotherapy, gender, ethnicity, body mass index, cancer diagnosis, chemotherapy regimen, colony stimulating factor use, first cycle dose modifications and baseline blood values. Baseline blood values included neutrophils, platelets, haemoglobin, creatinine and bilirubin. Shrinkage was used to adjust for overoptimism of predictor effects. For internal validation (of the full models in the development data) we computed the ability of the models to discriminate between those with and without poor outcomes (c-statistic), and the agreement between predicted and observed risk (calibration slope). Net benefit was used to understand the risk thresholds where the model would perform better than the 'treat all' or 'treat none' strategies.

RESULTS

A total of 4604 patients were included in our study of whom 628 (13.6%) incurred a 7-day delay to the second cycle of chemotherapy. Delay-7 showed good discrimination and calibration, with c-statistic of 0.68 (95% confidence interval 0.66-0.7), following internal validation and calibration-in-the-large of -0.006.

CONCLUSIONS

Delay-7 predicts a patient's individualised risk of a treatment-related delay at cycle two of treatment. The score can be used to stratify interventions to reduce the occurrence of treatment-related toxicity.

1362 ANTICHOLINERGIC PRESCRIBING HABITS AND ITS ASSOCIATIONS IN A COMMUNITY POPULATION OF PEOPLE LIVING WITH DEMENTIA

Introduction

Many commonly prescribed medications have inadvertent anticholinergic effects. People with Dementia (PwD) are more vulnerable to these effects and at risk of adverse outcomes, the risk being higher with a greater degree of anticholinergic exposure. We investigated prescribing patterns and Anticholinergic burden (ACB) in a cohort of community-dwelling older adults with dementia and aimed to explore the effect of ACB on cognition, mood, and quality of life(QoL).

Method

The medication and demographic information for 87 (39 female) community-dwelling PwD were obtained from Electronic Care Summaries. We used the German Anticholinergic Burden Scale (GABS) to measure ACB. Additionally, we investigated associations between ACB and cognitive (ADAS-Cog), functional (BADL) and QoL (DemQoL) assessments.

Results

28.7% of participants had a clinically significant score (ACB&gt; 2). The most commonly prescribed medications with ACB were Lansoprazole(18.3%), Mirtazapine(12.6%) and Codeine(12.6%). ACB was higher in males and negatively correlated with age, r(87)=-.21,p=.03. There was no association between ACB and cognition, QoL, functional independence, and neuropsychiatric symptoms. Over six months, PLWD with no ACB had a greater negative change in neuropsychiatric symptoms[t(18)=2.27,p=.04] and functional independence[t(23)=-3.8,p=.001], indicating greater dependence and worsening neuropsychiatric symptoms.

Conclusion

A third of PLWD in the community had clinically significant ACB. No ACB was associated with worsening neuropsychiatric symptoms and functional dependence over a six-month period. Community prescribers should consider regular medication reviews with PLWD and carers to ensure medications are prescribed safely and appropriately.

Validating low-fidelity arthroscopic simulation in medical students: a feasibility trial

INTRODUCTION

With surgical opportunities becoming increasingly restricted for orthopaedic trainees, simulation training is a valuable alternative at providing sufficient practice. This pilot study aims to assess the potential effectiveness of low-fidelity simulation in teaching medical students basic arthroscopic skills and the feasibility of its incorporation into formal student training programmes.

METHODS

Twenty-two medical students completed pre- and post-training tests on the Probing (Task 1) and Maze (Task 2) exercises from the Sawbones 'Fundamentals of Arthroscopy Surgery Training' (FAST) programme. Training consisted of practising horizon control, deliberate linear motion and probing within 25min over a period of days. Completion time and error frequency were measured. The difference in performance was assessed using a paired two-tailed t-test. Qualitative data were collected.

RESULTS

Test completion time decreased significantly by a mean of 83s (±46s, 95% confidence intervals [CI] 37 to 129) for Task 1 (p=0.001) and 105s (±55s, 95% CI 50 to 160) for Task 2 (p=0.0007). Frequency of direct visualisation errors decreased significantly by a mean of 1.0 errors (±1.0 errors, 95% CI 0.1 to 2.0) for Task 1 (p = 0.04) and 0.8 errors (±0.8 errors, 95% CI 0.1 to 1.6) for Task 2 (p = 0.04). At post-training, 82% of participants were willing to incorporate FAST into formal training.

CONCLUSIONS

Low-fidelity simulators such as FAST can potentially teach basic arthroscopic skills to medical students and are feasible for incorporation into formal training. They also give students a cost-effective and safe basic surgical training experience.

Metal nanoparticles produced by plants with antibacterial properties against Staphylococcus aureus

Staphylococcus aureus (S. aureus) is a pathogenic bacteria that causes a variety of potentially fatal infections. The emergence of antibiotic-resistant strains of S. aureus has made treatment even more difficult. In recent years, nanoparticles have been used as an alternative therapeutic agent for S. aureus infections. Among various methods for the synthesis of nanoparticles, the method utilizing plant extracts from different parts of a plant, such as root, stem, leaf, flower, seeds, etc. is gaining widespread usage. Phytochemicals present in plant extract are an inexpensive, eco-friendly, natural material that act as reducing and stabilization agent for the nanoparticle synthesis. The utilization of plant-fabricated nanoparticles against S. aureus is currently in trend. The current review discusses recent findings in the therapeutic application of phytofabricated metal-based nanoparticles against Staphylococcus aureus.

Cytosolic aldose metabolism contributes to progression from cirrhosis to hepatocarcinogenesis

Oxidative stress modulates carcinogenesis in the liver; however, direct evidence for metabolic control of oxidative stress during pathogenesis, particularly, of progression from cirrhosis to hepatocellular carcinoma (HCC), has been lacking. Deficiency of transaldolase (TAL), a rate-limiting enzyme of the non-oxidative branch of the pentose phosphate pathway (PPP), restricts growth and predisposes to cirrhosis and HCC in mice and humans. Here, we show that mitochondrial oxidative stress and progression from cirrhosis to HCC and acetaminophen-induced liver necrosis are critically dependent on NADPH depletion and polyol buildup by aldose reductase (AR), while this enzyme protects from carbon trapping in the PPP and growth restriction in TAL deficiency. Both TAL and AR are confined to the cytosol; however, their inactivation distorts mitochondrial redox homeostasis in opposite directions. The results suggest that AR acts as a rheostat of carbon recycling and NADPH output of the PPP with broad implications for disease progression from cirrhosis to HCC.

Utility of sirolimus coated balloons in the peripheral vasculature – a review of the current literature

Sirolimus-coated balloons (SCB) have demonstrated much promise as an alternative drug eluting device to the existing paclitaxel coated balloon platforms for the treatment of peripheral arterial disease (PAD). They have been well tested pre-clinically and have demonstrated anti-restenotic effects as well as clinical safety in its use for treatment of coronary artery disease. The existing approved SCBs have thus far demonstrated good short-term patency (12-months) and did not exhibit any major adverse events or device related shortcomings in its use for treatment of PAD. There are several studies ongoing which aim to further investigate the efficacy of existing SCBs and establish a direct comparison of its outcomes compared with plain balloon angioplasty. Also, SCB utility to salvage failing arteriovenous fistulas for haemodialysis patients has also been explored. We review the current progress made in the establishment of SCB in the treatment of PAD as well as highlight ongoing studies investigating the role of SCB in various settings.

LBODP073 Non-functioning Pituitary Macroadenoma Presenting As Osteopenia In A Male

Non-functioning pituitary macroadenomas (NFPAs) account for 14-54% of all pituitary adenomas. NFPAs are benign, but mass effects may lead to significant symptoms, including visual impairment and pituitary insufficiency, of which secondary hypogonadism is present in 75% of reported cases. Patients with hypogonadism may experience decreased bone density, libido, muscle mass/strength, and fatigue. We describe a patient who presented with osteopenia, in addition to atypical symptoms of secondary hypogonadism, associated with low testosterone levels. Further workup disclosed a large pituitary macroadenoma. A 56-year-old male presented to the clinic for a two-year history of diffuse joint pain. X-rays were significant for bone loss. This led to a bone density scan that showed osteopenia with a T score of -2.3 in the lumbar spine and left femoral neck. He had no prior history of fractures or loss in height. Risk factors for bone disease were only pertinent for history of osteoporosis in his mother. He was referred to endocrinology for further evaluation. Work up included normal vitamin D levels, 24-hour urine calcium excretion, morning cortisol, and TSH. Given the patient's osteopenia and additional complaints of decreased appetite, weight loss, fatigue, and muscle weakness, testosterone levels were checked and found to be low. Free testosterone level was 14.3 pg/ml with inappropriately low FSH and LH. Prolactin was normal at 12.5 ng/ml. He subsequently had an MRI brain which revealed a pituitary macroadenoma measuring 2. 0×2.4×2.4 cm with mass effect on the optic chiasm. However, the patient did not complain of headaches or visual disturbances and visual field testing was normal. He underwent transsphenoidal resection of the pituitary tumor which led to normalization of testosterone levels and resolution of all his symptoms. This case exemplifies how non-specific symptoms of hypogonadism and absence of mass effect symptoms can lead to a delay in diagnosis of NFPA. Typically, NFPAs are detected when they are large enough to cause symptoms of mass effect which, interestingly, were absent in this patient despite compression of the optic chiasm. Male hypogonadism increases the risk for bone disease. Thus, it is important to pursue work up for secondary hypogonadism in males presenting with osteopenia/osteoporosis despite lack of overt symptoms. A thorough history and workup are essential in diagnosing NFPA. Prompt detection of NFPA can facilitate timely management leading to clinical improvement. The first line of treatment for NFPAs causing neurological symptoms is transsphenoidal surgical resection. Surgery is also recommended for NFPAs that are at high risk for causing visual deficits due to involvement of optic chiasm, as was seen in this patient. Post-surgical follow up includes long-term routine monitoring of hormone levels and neuroimaging.

Presentation: No date and time listed

ODP471 Concomitant Metastatic Papillary Thyroid Cancer and Graves’ Disease Presenting as Thyroid Storm

Papillary thyroid cancer (PTC) is the most prevalent form of thyroid cancer with a reported incidence of 4.7-5.3 per 100,000 people over the past 10 years. PTC is more commonly seen in females during the fourth and fifth decades of life. Radiation exposure during childhood and family history are known risk factors for thyroid cancer. Thyroid cancer typically presents as a thyroid nodule detected on physical exam or incidental finding on imaging. Patients may feel swollen glands or a lump in the neck that can cause dysphagia. It is uncommon for PTC to present as hyperthyroidism. However, patients with Graves’ disease have an increased risk of thyroid cancer. We share a rare case of PTC detected following newly diagnosed Grave's disease presenting as thyroid storm. A 27-year-old male with history of polysubstance abuse and bipolar disorder presented to the hospital for altered mentation. He appeared anxious, tremulous, and was persistently tachycardic and febrile. There was an initial concern for drug intoxication or overdose. However, the patient's mother stated that he had not used drugs for the past six months and that his prescription bottles were appropriately filled. Blood alcohol level was elevated however urine toxicology screen was unrevealing. Due to worsening mentation and inability to protect his airway, the patient was intubated and transferred to the ICU. Thyroid levels were checked and TSH was less than 0. 01 with free T4 of 3.6 and free T3 of 13.80. The patient's Burch-Warsofsky score was 40. With endocrinology input, the patient was started on thyroid storm protocol with propylthiouracil, iodine solution, hydrocortisone, and beta blocker. He had significant improvement and was able to be extubated. Propylthiouracil was transitioned to methimazole. Thyroid stimulatingimmunoglobulin was found to be elevated, consistent with Grave's disease. Patient did have a known enlarged thyroid with heterogeneity from a recent ultrasound that had not yet been investigated. A CT scan of the neck was ordered, and this showed cervical lymphadenopathy, diffuse thyroid enlargement without nodule, and anterior mediastinum density. An ultrasound guided cervical lymph node biopsy was consistent with metastatic papillary thyroid cancer. A PET CT showed metastatic adenopathy in the upper neck and chest. Patient is planned to undergo thyroidectomy with lymphadenectomy. He is being followed by oncology and endocrinology for further management outpatient. Concurrent hyperthyroidism from Grave's disease with thyroid cancer is rare, though with increasing reports, particularly with PTC. Thyroid stimulatingimmunoglobulins are thought to accelerate thyroid cancer cell turnover and promote angiogenesis through up-regulation of vascular endothelial growth factors, facilitating invasive and metastatic potential. Thyroid cancer with coexisting hyperthyroidism has a poorer prognosis. Having a high clinical suspicion of thyroid cancer in patients with hyperthyroidism can result in prompter diagnosis and treatment which is imperative.

Presentation: No date and time listed

LBODP069 Parathyroid Crisis And Recalcitrant Hypercalcemia From Double Parathyroid Adenomas

Parathyroid crisis is a rare and life-threatening manifestation of hyperparathyroidism. Patients present with severe hypercalcemia and associated symptoms of bone disease, nephrolithiasis, abdominal pain, and fatigue. Multi-organ dysfunction in the form of encephalopathy, cardiac dysrhythmias, and renal failure is often present. There have also been reports of bleeding duodenal ulcers secondary to marked elevated parathyroid hormone. The most common etiology is a single parathyroid adenoma (85%) followed by hyperplasia (10%), double adenomas (4%), and carcinoma (1%). Parathyroid crisis requires immediate medical management of hypercalcemia and in recalcitrant cases, urgent parathyroidectomy. A 67-year-old female presented to the hospital with weakness and intermittent hematochezia. She was found to have acute renal failure, new onset anemia, and profound hypercalcemia of 17.1 mg/dl. On exam, she was slow to respond and exhibited diffuse muscle weakness. EKG showed sinus tachycardia, a right bundle branch block, and normal QTc. She received aggressive intravenous fluids and calcitonin. Bisphosphonate was not given due to renal failure. Due to refractory hypercalcemia, she was initiated on cinacalcet. She ultimately required hemodialysis due to failure of medical therapy. Further work-up showed a PTH of 2627 pg/ml. Vitamin D levels, TSH, and serum and urine protein electrophoresis were unremarkable. Renal ultrasound did not show nephrolithiasis. Given hematochezia and anemia in the setting of parathyroid crisis, endoscopy was done and was unrevealing of ulcers. A parathyroid ultrasound and nuclear medicine CT scan showed bilateral parathyroid adenomas. She underwent left superior and right inferior parathyroidectomy with biopsies revealing hypercellular parathyroid tissue with no features of malignancy. Following surgery, calcium levels gradually normalized. However, she remained dialysis dependent. This case exhibits a rare presentation of parathyroid crisis from double adenomas, requiring urgent double parathyroidectomy due to refractory hypercalcemia. This patient had an astoundingly elevated PTH level of 2627 pg/dl, one of the highest values documented in literature, which may attribute to the recalcitrant nature of hypercalcemia. Prompt diagnosis and treatment of parathyroid crisis is critical in preventing life-threatening complications.

Presentation: No date and time listed

OR03-3 Impact of Continuous Glucose Monitoring (CGM) on Lifestyle Modifications in Individuals with Prediabetes

Introduction

Adherence to lifestyle modifications can prevent diabetes; however, this poses a challenge for most individuals. CGM is an effective tool for glycemic control and lifestyle modifications in patients with diabetes on insulin therapy. We explored the impact of CGM use in individuals with prediabetes.

Hypothesis

Individuals using CGM in addition to diabetes education will show improved adherence to lifestyle modifications and greater reduction of HbA1c as compared to those receiving diabetes education alone.Design57 individuals with prediabetes were randomized to use CGM for 3 months along with diabetes education (CGM group) or receive diabetes education alone (EDU group). Food frequency (UKDDQ) and physical activity (IPAQ) questionnaires were completed by participants at the beginning and at the end of the study (6 months). Primary outcomes were lifestyle modifications and changes in HbA1c. Secondary outcomes were changes in weight and blood pressure.

Results

Both groups reported an increase in healthy food choices; however, EDU group performed better (EDU: 12.4 vs 9.2, p&lt;0.01, CGM: 10.6 vs 9.5, p 0.08). Unhealthy food choices were reduced in both groups. CGM group reported a greater increase in moderate physical activity levels (CGM: 230 vs 61 minutes/week, p 0.01, EDU: 78.5 vs 48 minutes/week, p 0.22). Vigorous physical activity was reported by more individuals in CGM group than EDU (35% vs 4%). Greater reduction in mean HbA1c was noted in CGM group (5.7 vs 5.9%, p 0.05) compared to EDU (5.8 vs 5.9%, p 0.01). 33% of participants in both groups had normalization of HbA1c at the end of study. CGM group had greater reduction in weight (3.5 vs 0.8 lb, p 0.1) and systolic BP (12 vs 2.4 mmHg, p 0.01) than EDU. Irrespective of group assignment, the study population had improvement in all outcomes despite the beginning of COVID-19 pandemic during 4th month of the study. Smaller number of participants in the CGM group reported negative impact of the pandemic on their lifestyle modifications than EDU (Diet: 68% vs 80%, Physical activity: 48% vs 64%). Majority of CGM group participants were able to maintain lifestyle changes after discontinuing CGM use (Diet: 72%, Physical activity: 84%). On comparing both interventions, 56% of CGM group participants felt CGM to be more helpful than education for lifestyle modifications, while 40% felt both interventions helped equally.

Conclusions

CGM use in addition to diabetes education resulted in improvement in physical activity, food choices, HbA1c, weight, and BP in individuals with prediabetes. The significance of diabetes education was noted by greater improvement in food choices in EDU group. CGM can be an effective tool for diabetes prevention with lifestyle modifications in prediabetes. The long-term impact of CGM use and cost-benefit analysis in high-risk patients needs to be explored further.

Presentation: Saturday, June 11, 2022 12:00 p.m. - 12:15 p.m.

National audit of non-melanoma skin cancer excisions performed by plastic surgery in the UK

A national, multi-centre audit of non-melanoma skin cancer excisions by plastic surgery.

Physical activity, sedentary time and breast cancer risk: a Mendelian randomisation study

OBJECTIVES

Physical inactivity and sedentary behaviour are associated with higher breast cancer risk in observational studies, but ascribing causality is difficult. Mendelian randomisation (MR) assesses causality by simulating randomised trial groups using genotype. We assessed whether lifelong physical activity or sedentary time, assessed using genotype, may be causally associated with breast cancer risk overall, pre/post-menopause, and by case-groups defined by tumour characteristics.

METHODS

We performed two-sample inverse-variance-weighted MR using individual-level Breast Cancer Association Consortium case-control data from 130 957 European-ancestry women (69 838 invasive cases), and published UK Biobank data (n=91 105-377 234). Genetic instruments were single nucleotide polymorphisms (SNPs) associated in UK Biobank with wrist-worn accelerometer-measured overall physical activity (nsnps=5) or sedentary time (nsnps=6), or accelerometer-measured (nsnps=1) or self-reported (nsnps=5) vigorous physical activity.

RESULTS

Greater genetically-predicted overall activity was associated with lower breast cancer overall risk (OR=0.59; 95% confidence interval (CI) 0.42 to 0.83 per-standard deviation (SD;~8 milligravities acceleration)) and for most case-groups. Genetically-predicted vigorous activity was associated with lower risk of pre/perimenopausal breast cancer (OR=0.62; 95% CI 0.45 to 0.87,≥3 vs. 0 self-reported days/week), with consistent estimates for most case-groups. Greater genetically-predicted sedentary time was associated with higher hormone-receptor-negative tumour risk (OR=1.77; 95% CI 1.07 to 2.92 per-SD (~7% time spent sedentary)), with elevated estimates for most case-groups. Results were robust to sensitivity analyses examining pleiotropy (including weighted-median-MR, MR-Egger).

CONCLUSION

Our study provides strong evidence that greater overall physical activity, greater vigorous activity, and lower sedentary time are likely to reduce breast cancer risk. More widespread adoption of active lifestyles may reduce the burden from the most common cancer in women.