Synthetic biology approaches for enhancing safety and specificity of CAR-T cell therapies for solid cancers.

CAR-T cell therapies have been successful in treating numerous hematologic malignancies as the T cell can be engineered to target a specific antigen associated with the disease. However, translating CAR-T cell therapies for solid cancers is proving more challenging due to the lack of truly tumor-associated antigens and the high risk of off-target toxicities. To combat this, numerous synthetic biology mechanisms are being incorporated to create safer and more specific CAR-T cells that can be spatiotemporally controlled with increased precision. Here, we seek to summarize and analyze the advancements for CAR-T cell therapies with respect to clinical implementation, from the perspective of synthetic biology and immunology. This review should serve as a resource for further investigation and growth within the field of personalized cellular therapies.

Spontaneous pneumomediastinum and pneumopericardium in a young male with asthma.

INTRODUCTION: Spontaneous pneumomediastinum with pneumopericardium is an uncommon clinical entity. CASE STUDY: Here, we report the case of a 23-year-old male with asthma who presented with acute chest pain and shortness of breath after an episode of coughing and sneezing. CT scans of the chest and neck revealed pneumomediastinum and pneumopericardium with extensive subcutaneous emphysema extending into the axilla and neck. RESULTS: The patient was admitted for observation and analgesia. No other interventions were administered. Interval scans performed on day five of the admission demonstrated an interval reduction in the degree of air within the mediastinum, pericardium and subcutaneous tissues, and the patient was subsequently discharged home. CONCLUSION: This case outlines the presentation, diagnosis, and management of concurrent spontaneous pneumomediastinum and pneumopericardium.

Clinical and cellular phenotypes resulting from a founder mutation in IL10RB.

Inborn errors of immunity are a group of rare genetically determined diseases that impair immune system development or function. Many of these diseases include immune dysregulation, autoimmunity or autoinflammation as prominent clinical features. In some children diagnosed with very early onset inflammatory bowel disease (VEOIBD), monogenic inborn errors of immune dysregulation underlie disease. We report a case of VEOIBD caused by a novel homozygous loss of function mutation in IL10RB. We use CyTOF with a broad panel of antibodies to interrogate the immunophenotype of this patient and detect reduced frequencies of CD4 and CD8 T cells with additional defects in some populations of T helper cells, innate-like T cells and memory B cells. Finally, we identify the patient's mutation as a founder allele in an isolated indigenous population and estimate the age of this variant by studying the shared ancestral haplotype.

Proteomics identifies the developmental regulation of HKDC1 in liver of pigs and mice.

During the perinatal period, unique metabolic adaptations support energetic requirements for rapid growth. To gain insight into perinatal adaptations, quantitative proteomics was performed comparing the livers of Yorkshire pigs at postnatal day 7 and adult. These data revealed differences in the metabolic control of liver function including significant changes in lipid and carbohydrate metabolic pathways. Newborn livers showed an enrichment of proteins in lipid catabolism and gluconeogenesis concomitant with elevated liver carnitine and acylcarnitines levels. Sugar kinases were some of the most dramatically differentially enriched proteins compared with neonatal and adult pigs including galactokinase 1 (Galk1), ketohexokinase (KHK), hexokinase 1 (HK1), and hexokinase 4 (GCK). Interestingly, hexokinase domain containing 1 (HKDC1), a newly identified fifth hexokinase associated with glucose disturbances in pregnant women, was highly enriched in the liver during the prenatal and perinatal periods and continuously declined throughout postnatal development in pigs and mice. These changes were confirmed via Western blot and mRNA expression. These data provide new insights into the developmental and metabolic adaptations in the liver during the transition from the perinatal period to adulthood in multiple mammalian species.

Is preoperative hypoalbuminemia or hypoproteinemia a reliable marker for anastomotic leakage risk in patients undergoing elective colorectal surgery in an enhanced recovery after surgery (ERAS) program?

PURPOSE: Preoperative hypoalbuminemia has traditionally been used as a marker of nutritional status and is considered a significant risk factor for anastomotic leak (AL). METHODS: The Westmead Enhanced Recovery After Surgery (WERAS) prospectively collected database, consisting of 361 patients who underwent colorectal surgery with primary anastomosis, was interrogated. Preoperative serum albumin and protein levels (measured within 1 week of surgery) were plotted on receiver operating characteristic curves (ROC curves) and statistically analyzed for cutoff values, sensitivity, specificity, positive predictive values (PPV), and negative predictive values (NPV). RESULTS: The incidence of AL was 4.4% (16/361). Overall mortality was 1.4% (5/361), 6.3% (1/16) in the AL group, and 1.2% (4/345) in the no AL group. The median preoperative albumin and protein level in the AL group were 39 g/L and 75 g/L, respectively. The median preoperative albumin and protein level in the no AL group were 38 g/L and 74 g/L, respectively. The Mann-Whitney U test showed no statistically significant difference in albumin levels (p = 0.4457) nor protein levels (p = 0.6245) in the AL and no AL groups. ROC curves demonstrated that preoperative albumin and protein levels were not good predictors of anastomotic leak. Cutoff values for albumin (38 g/L) and protein (75 g/L) both had poor PPV for AL (4.8% and 3.8% respectively). CONCLUSION: In patients undergoing elective colorectal surgery as part of an ERAS program, preoperative serum albumin and protein levels are not reliable in predicting AL. This may be because of nutritional supplementation provided as part of an ERAS program may correct nutritional deficits to protect against AL or that low albumin/protein is not as robust a marker of AL as previously reported.

The Utility of the Oncotype DX Test for Breast Cancer Patients in an Australian Multidisciplinary Setting.

Introduction: The Oncotype DX test is a genomic assay that generates a Recurrence Score (RS) predicting the 10-year risk of recurrence and response to adjuvant chemotherapy in ER+/HER2- breast cancer patients. The aims were to determine breast cancer distant recurrence and correlate with adjuvant chemoendocrine prescribing patterns based on the Oncotype DX recurrence score. Methods: We conducted a retrospective single-institution case series of 71 patients who had Oncotype DX assay testing after definitive surgery between 2012 and 2016. Both node-positive and node-negative patients were included. Patients were divided into Oncotype DX low risk (RS < 11) (n = 10, 14%), intermediate risk (RS 11-25) (n = 45, 63%), and high risk (RS > 25) (n = 16, 23%). Median follow-up was 6.1 years (range 4-8.9 years). Adjuvant treatment regimens and oncological outcomes were determined. Results. Mean age at diagnosis was 56 years (range, 33-77). Invasive ductal carcinoma (IDC) accounted for the majority (87%), with most tumors measuring between 10-20 mm (52%). 48% of the cohort were node positive. 15 of 16 high-risk patients (94%) received chemotherapy. 96% of intermediate-risk patients received endocrine therapy alone, one patient received chemoendocrine therapy (2%), and one declined systemic therapy (2%). In the low-risk group, 100% received endocrine therapy only. The high-risk group had the lowest mean ER% (P < 0.05), greatest mean mitotic rate (P < 0.05), and greatest proportion of Ki67% > 14. Five patients developed distant recurrence (7%): three from the intermediate-risk group (7%), one from the low-risk group (10%), and one from the high-risk group (6%). Conclusion: This is the first Australian study reporting the experience with medium-term recurrence outcomes of using the Oncotype DX assay in breast cancer. Chemotherapy was rarely given for patients with low-to-intermediate RS and always offered in high RS. This pattern of prescribing was associated with low rates of distant recurrence. National funding models should be considered.

Gastric Injury at Laparoscopy for Gynecologic Indications: A Systematic Review.

OBJECTIVE: This systematic review aims to identify causes of increased risk for and location and mechanism of gastric injury at laparoscopy for gynecologic indications and determine optimal management. DATA SOURCES: A prospectively registered systematic review (PROSPERO: CRD42021237999) was undertaken and performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Databases searched included Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Medline, Embase, Web of Science, SCOPUS, and Google Scholar from 1960 to 2021. METHODS OF STUDY SELECTION: All study types were included involving female patients of any age with gastric injury at laparoscopy for gynecologic indication. TABULATION, INTEGRATION, AND RESULTS: A total of 6294 articles were screened, from which 67 studies were selected for a full-text review. Twenty-eight articles were included, which contained 42 cases drawn from 7 observational studies, 4 case series, and 17 case reports. Of these, 93% (39/42) were at the time of laparoscopic entry, with Veress entry technique used in 79% of these cases (31/39). Eighteen cases reported an entry point, with 77% (14/18) occurring at the periumbilical entry point and 11% (2/18) occurring at Palmer's point. Of the cases with reported etiology for gastric distention or displacement, 64% (9/14) were owing to anesthetic cause. The most common sites of gastric injury were on the anterior stomach wall (n = 8) and the greater curvature (n = 5). Among patients with reported management (32/42), a similar proportion were managed conservatively (11) when compared with repair through laparotomy (13) or laparoscopy (8). All injuries were detected intraoperatively with no reported short-term sequelae. CONCLUSION: This systematic review of the literature reveals that gastric injury at laparoscopy for gynecologic indications is a rare complication predominantly occurring during laparoscopic entry, most commonly at the periumbilical entry point. When detected intraoperatively, conservative management, laparoscopic, or open repair in the appropriate patient has been performed with no short-term sequelae. The limitations of this review include paucity of cases, detail, and timeline of publications.

Functional loss of ketogenesis in odontocete cetaceans.

Odontocete cetaceans exhibit genomic mutations in key ketogenesis genes. In order to validate an inferred lack of ketogenesis made by observations from genome sequencing, we biochemically analyzed tissues from several odontocete cetacean species and demonstrate that they indeed do not exhibit appreciable hepatic ß-hydroxybutyrate (ßHB) or its carnitine ester. Furthermore, liver tissue exhibited significantly lower long chain acylcarnitines and increased odd chain acylcarnitines indicative of a decreased reliance on hepatic long chain fatty acid oxidation in these carnivorous mammals. Finally, we performed single molecule, real-time next generation sequencing of liver and brain RNA of Tursiops truncatus and demonstrate that the succinyl-CoA transferase required for acetoacetate catabolism is expressed in the nervous system. These data show that odontocete cetaceans have lost the ability to perform ketogenesis and suggest a hepatocentric coenzyme A recycling function rather than a predominantly systemic-bioenergetic role for ketogenesis in other ketogenic competent mammals such as humans.

Barrier enclosure use during aerosol-generating medical procedures: A scoping review.

INTRODUCTION: Barrier enclosure devices were introduced to protect against infectious disease transmission during aerosol generating medical procedures (AGMP). Recent discussion in the medical community has led to new designs and adoption despite limited evidence. A scoping review was conducted to characterize devices being used and their performance. METHODS: We conducted a scoping review of formal databases (MEDLINE, Embase, Cochrane Database of Systematic Reviews, CENTRAL, Scopus), grey literature, and hand-searched relevant journals. Forward and reverse citation searching was completed on included articles. Article/full-text screening and data extraction was performed by two independent reviewers. Studies were categorized by publication type, device category, intended medical use, and outcomes (efficacy - ability to contain particles; efficiency - time to complete AGMP; and usability - user experience). RESULTS: Searches identified 6489 studies and 123 met criteria for inclusion (k = 0.81 title/abstract, k = 0.77 full-text). Most articles were published in 2020 (98%, n = 120) as letters/commentaries (58%, n = 71). Box systems represented 42% (n = 52) of systems described, while plastic sheet systems accounted for 54% (n = 66). The majority were used for airway management (67%, n = 83). Only half of articles described outcome measures (54%, n = 67); 82% (n = 55) reporting efficacy, 39% (n = 26) on usability, and 15% (n = 10) on efficiency. Efficacy of devices in containing aerosols was limited and frequently dependent on use of suction devices. CONCLUSIONS: While use of various barrier enclosure devices has become widespread during this pandemic, objective data of efficacy, efficiency, and usability is limited. Further controlled studies are required before adoption into routine clinical practice.

Orthopaedic Manifestations of Transverse Myelitis in Children.

BACKGROUND: Transverse myelitis (TM) is a rare inflammatory disorder of the spinal cord. It can have a heterogeneous presentation with sensory, motor, and autonomic dysfunction. Neurological sequelae of TM include autonomic dysfunction, motor weakness, and/or spasticity. Studies describing orthopaedic deformities and treatments associated with TM are nonexistent. This purpose of this study was to describe the orthopaedic manifestations of TM in children. METHODS: A multicenter retrospective review was conducted of patients, 0 to 21 years of age, with TM presenting over a 15-year period at 4 academic children's hospitals. Those with confirmed diagnosis of TM and referred to an orthopaedic surgeon were included. Demographics, orthopaedic manifestations, operative/nonoperative treatments, and complications were recorded. Descriptive statistics were used for data reporting. RESULTS: Of 119 patients identified with TM, 37 saw an orthopaedic surgeon. By etiology, 23 were idiopathic (62%), 10 infectious (27%), 3 (8%) inflammatory/autoimmune, and 1 (3%) vascular. The mean age at diagnosis was 6.7 (SD: 5.5) years and at orthopaedic presentation was 8.4 (SD: 5.2) years. Orthopaedic manifestations included scoliosis in 13 (35%), gait abnormalities in 7 (19%), foot deformities in 7 (19%), upper extremity issues in 7 (19%), symptomatic spasticity in 6 (16%), lower extremity muscle contractures in 6 (16%), fractures in 6 (16%), hip displacement in 3 (8%), pain in 2 (5%), and limb length discrepancy in 2 (5%) patients. Seven children (19%) were seen for establishment of care. In all, 14 (38%) underwent operative intervention, mainly for soft-tissue and scoliosis management. Four patients had baclofen pump placement for spasticity management. Postoperative complications occurred in 36% of cases, most commonly because of infection. Neither topographic pattern nor location of lesion had a significant relationship with need for hip or spine surgery. CONCLUSIONS: This report describes the orthopaedic manifestations associated with TM in children, nearly 40% of whom required operative intervention(s). Understanding the breadth of musculoskeletal burden incurred in TM can help develop surveillance programs to identify and treat these deformities in a timely manner. LEVEL OF EVIDENCE: Level IV.

Loss of macrophage fatty acid oxidation does not potentiate systemic metabolic dysfunction.

Fatty acid oxidation in macrophages has been suggested to play a causative role in high-fat diet-induced metabolic dysfunction, particularly in the etiology of adipose-driven insulin resistance. To understand the contribution of macrophage fatty acid oxidation directly to metabolic dysfunction in high-fat diet-induced obesity, we generated mice with a myeloid-specific knockout of carnitine palmitoyltransferase II (CPT2 Mϕ-KO), an obligate step in mitochondrial long-chain fatty acid oxidation. While fatty acid oxidation was clearly induced upon IL-4 stimulation, fatty acid oxidation-deficient CPT2 Mϕ-KO bone marrow-derived macrophages displayed canonical markers of M2 polarization following IL-4 stimulation in vitro. In addition, loss of macrophage fatty acid oxidation in vivo did not alter the progression of high-fat diet-induced obesity, inflammation, macrophage polarization, oxidative stress, or glucose intolerance. These data suggest that although IL-4-stimulated alternatively activated macrophages upregulate fatty acid oxidation, fatty acid oxidation is dispensable for macrophage polarization and high-fat diet-induced metabolic dysfunction. Macrophage fatty acid oxidation likely plays a correlative, rather than causative, role in systemic metabolic dysfunction.

Neurometabolic roles of ApoE and Ldl-R in mouse brain.

Polymorphisms in ApoE are highly correlated with the progression of neurodegenerative disease, in particular Alzheimer's disease. Little is known, however, about the role of ApoE or cholesterol metabolism on brain neurochemistry in general. To better understand the role of lipoprotein and cholesterol metabolism in the brain, we profiled 6 and 12-week old Apoe KO and Ldlr KO mouse models via unbiased metabolomics to determine which metabolites were affected at an early age to identify those that may play a role in triggering pathology later in life. Steady-state metabolomics revealed only subtle differences among Apoe KO, Ldlr KO and WT mouse brains. Ldlr KO mice exhibited alterations in metabolites involved in neurotransmitter, amino acid and cholesterol metabolism. In contrast, Apoe KO mice only showed subtle changes in amino acid and neurotransmitter metabolism. These subtle changes in a broad range of metabolites indicate that ApoE and Ldl-R alone may not play a significant role in these mouse models at an early age, but instead require the cumulative effect from different pathways that lead to dysfunction at a much later stage of life.

Paraxial full-field cloaking.

We complete the 'paraxial' (small-angle) ray optics cloaking formalism presented previously [Opt. Express 22, 29465 (2014)], by extending it to the full-field of light. Omnidirectionality is then the only relaxed parameter of what may be considered an ideal, broadband, field cloak. We show that an isotropic plate of uniform thickness, with appropriately designed refractive index and dispersion, can match the phase over the whole visible spectrum. Our results support the fundamental limits on cloaking for broadband vs. omnidirectionality, and provide insights into when anisotropy may be required.

Mechanism of raloxifene-induced upregulation of glutamate transporters in rat primary astrocytes.

Raloxifene (RX), a selective estrogen receptor modulator (SERM), exerts neuroprotection in multiple clinical and experimental settings. Astrocytic glutamate transporters GLT-1 (EAAT2) and GLAST (EAAT1) are the main glutamate transporters in the central nervous system, taking up most of excess glutamate from the synaptic cleft to prevent excitotoxic neuronal death. Since drugs targeting astrocytic glutamate transporters to enhance their expression and function represent potential therapeutics for neurodegenerative disorders associated with excitotoxicity, we tested if RX modulates the expression and function of GLT-1 and GLAST in rat primary astrocytes. The results showed that RX significantly increased glutamate uptake and expression of GLT-1 mRNA and protein levels. RX enhanced GLT-1 expression by the activation of multiple signaling pathways including ERK, EGFR, and CREB mediated by estrogen receptors (ERs) ER-α, ER-ß, and GPR30. At the transcriptional level, NF-κB played a critical role in RX-induced GLT-1 expression as RX increased NF-κB reporter activity and induced binding of NF-κB p65 and p50 to the GLT-1 promoter. RX attenuated the reduction of GLT-1 expression and glutamate uptake induced by manganese (Mn) whose chronic high levels of exposure cause manganism. RX also upregulated GLAST by increasing its promoter activity and protein levels via the NF-κB pathway and ERs. Our findings provide new insight into the mechanism of RX-induced enhancement of GLT-1 and GLAST expression, as well as the attenuation of Mn-reduced expression of these transporters. These findings will be highly valuable for developing therapeutics of neurodegenerative diseases associated with impaired astrocytic glutamate transporters.

Paraxial ray optics cloaking.

Despite much interest and progress in optical spatial cloaking, a three-dimensional (3D), transmitting, continuously multidirectional cloak in the visible regime has not yet been demonstrated. Here we experimentally demonstrate such a cloak using ray optics, albeit with some edge effects. Our device requires no new materials, uses isotropic off-the-shelf optics, scales easily to cloak arbitrarily large objects, and is as broadband as the choice of optical material, all of which have been challenges for current cloaking schemes. In addition, we provide a concise formalism that quantifies and produces perfect optical cloaks in the small-angle ('paraxial') limit.

Amplitude-only, passive, broadband, optical spatial cloaking of very large objects.

We demonstrate three amplitude cloaks that can hide very large spatial objects over the entire visible spectrum using only passive, off-the-shelf optics. The cloaked region for all of the devices exceeds 106 mm³, with the largest exceeding 108 mm³. Although unidirectional, these cloaks can hide the cloaked object, even if the object is transversely illuminated or self-illuminated. Due to the small usable solid angle, but simple scaling, these cloaks may be of value in hiding small field-of-view objects such as mid- to high-earth orbit satellites from earth-based observation. Active phase front manipulation can also make these cloaks invisible to some forms of image homodyning.

Conservative Treatment of an Unusual Presentation of Iliopsoas Phlegmon Related to Infected Intrauterine Contraceptive Device.

Iliopsoas phlegmon/abscess is uncommon, and individuals often present with nonspecific symptoms. Diagnosis is often delayed and almost always requires advanced imaging techniques such as computed tomography or magnetic resonance imaging. We report a case of a 51-year-old woman who presented with right lower limb swelling and associated rash with imaging demonstrating iliopsoas abscess secondary to an infected intrauterine contraceptive device. This rare case highlights the nonspecific presentation of iliopsoas abscess and the need to consider unusual sources of infection such as an intrauterine contraceptive device in women presenting with iliopsoas phlegmon and abscess.

Immune dysregulation due to bi-allelic mutation of the actin remodeling protein DIAPH1.

Children with severe inflammatory diseases are challenging to diagnose and treat, and the etiology of disease often remains unexplained. Here we present DIAPH1 deficiency as an unexpected genetic finding in a child with fatal inflammatory bowel disease who also displayed complex neurological and developmental phenotypes. Bi-allelic mutations of DIAPH1 were first described in patients with a severe neurological phenotype including microcephaly, intellectual disability, seizures, and blindness. Recent findings have expanded the clinical phenotype of DIAPH1 deficiency to include severe susceptibility to infections, placing this monogenic disease amongst the etiologies of inborn errors of immunity. Immune phenotypes in DIAPH1 deficiency are largely driven aberrant lymphocyte activation, particularly the failure to form an effective immune synapse in T cells. We present the case of a child with a novel homozygous deletion in DIAPH1, leading to a premature truncation in the Lasso domain of the protein. Unlike other cases of DIAPH1 deficiency, this patient did not have seizures or lung infections. Her major immune-related clinical symptoms were inflammation and enteropathy, diarrhea and failure to thrive. This patient did not show T or B cell lymphopenia but did have dramatically reduced naïve CD4+ and CD8+ T cells, expanded CD4-CD8- T cells, and elevated IgE. Similar to other cases of DIAPH1 deficiency, this patient had non-hematological phenotypes including microcephaly, developmental delay, and impaired vision. This patient's symptSoms of immune dysregulation were not successfully controlled and were ultimately fatal. This case expands the clinical spectrum of DIAPH1 deficiency and reveals that autoimmune or inflammatory enteropathy may be the most prominent immunological manifestation of disease.

An Unusual Case of Lethal Strongyloides stercoralis-Associated Chronic Fulminant Colitis in an Immunocompetent Patient.

A 70-year-old immunocompetent Lebanese male presented with 3-month history of watery diarrhoea and abdominal pain after recently arriving to Australia from Lebanon. He had a colectomy for an iatrogenic bowel perforation associated with a colonoscopy in Lebanon several months prior. His computed tomography (CT) scan demonstrated pancolitis. Stool culture and polymerase chain reaction (PCR) were positive for Strongyloides stercoralis. Despite Strongyloides treatment and total parenteral nutrition, his pancolitis unexpectedly persisted despite negative stool cultures, and the patient failed to progress over several weeks with worsening abdominal pain. A colectomy was considered. However, due to his recent myocardial infarct requiring cardiac stenting, his anticoagulant and antiplatelets could not be ceased for at least 3 months without significant cardiac risk. After hospitalisation for several weeks in Australia, he was discharged against medical advice and flew back to Lebanon, where he presented with worsening pain and underwent a subtotal colectomy. Unfortunately, he developed multiorgan failure and died 3 weeks following his colectomy. Strongyloides-related pancolitis is a rare condition in immunocompetent adults that has the potential to persist and be lethal, despite microbiological antiparasitic eradication.

Pathological and clinical outcomes following neoadjuvant dual HER2 therapy for early-stage breast cancer: An Australian institutional real-world experience.

AIM: There has been significant progress made in developing novel targeted therapies in the neoadjuvant setting for non-metastatic HER2-positive breast cancer, which may be used in combination with conventional chemotherapy to optimise pathological responses at surgery. However, these therapies, particularly the chemotherapeutic components, may portend significant and long-lasting toxicity. Hence, de-escalation of treatment intensity has been an area of interest and was evaluated in the phase II NeoSphere study. Herein, we report the real-world pathological and survival outcomes from neoadjuvant taxane and dual HER2 blockade recorded at our centre. METHODS: This was a retrospective cohort study of patients receiving neoadjuvant pertuzumab, trastuzumab and taxane chemotherapy for non-metastatic HER2-positive breast cancer at a single centre in Sydney, Australia. We collected data pertaining to baseline demographic characteristics, pathological response rates, post-surgical prescribing patterns and also undertook survival analyses for invasive disease-free survival (iDFS) as well as exploratory analyses for correlations between pre-specified clinicopathologic factors and pathological response at surgery. RESULTS: Our population was largely similar at baseline to the NeoSphere study. 71 patients were included in the final analysis. 61% achieved a pathological complete response (pCR). Three patients received conventional chemotherapy in the adjuvant setting. 92% of included patients were alive and disease-free at 3 years of follow-up. Only 3 events of recurrence or death were recorded at a median follow-up of 32 months. No significant difference in iDFS was noted between patients achieving pCR and those with residual disease at surgery. CONCLUSION: This study demonstrates that de-escalated adjuvant treatment for HER2-positive early breast cancer achieved favourable pathological and long-term outcomes comparable to large trials, some utilising more intensive chemotherapeutic components.