Biallelic ATP2B1 variants as a likely cause of a novel neurodevelopmental malformation syndrome with primary hypoparathyroidism.

ATP2B1 encodes plasma membrane calcium-transporting-ATPase1 and plays an essential role in maintaining intracellular calcium homeostasis that regulates diverse signaling pathways. Heterozygous de novo missense and truncating ATP2B1 variants are associated with a neurodevelopmental phenotype of variable expressivity. We describe a proband with distinctive craniofacial gestalt, Pierre-Robin sequence, neurodevelopmental and growth deficit, periventricular heterotopia, brachymesophalangy, cutaneous syndactyly, and persistent hypocalcemia from primary hypoparathyroidism. Proband-parent trio exome sequencing identified compound heterozygous ATP2B1 variants: a maternally inherited splice-site (c.3060+2 T > G) and paternally inherited missense c.2938 G > T; p.(Val980Leu). Reverse-transcription-PCR on the proband's fibroblast-derived mRNA showed aberrantly spliced ATP2B1 transcripts targeted for nonsense-mediated decay. All correctly-spliced ATP2B1 mRNA encoding p.(Val980Leu) functionally causes decreased cellular Ca2+ extrusion. Immunoblotting showed reduced fibroblast ATP2B1. We conclude that biallelic ATP2B1 variants are the likely cause of the proband's phenotype, strengthening the association of ATP2B1 as a neurodevelopmental gene and expanding the phenotypic characterization of a biallelic loss-of-function genotype.

Management of acute perianal abscess: is surgeon specialization associated with improved outcomes?

BACKGROUND: Acute surgical units (ASU) are increasingly being adopted and in our system are staffed by colorectal and non-colorectal general surgeons. This study aims to evaluate whether surgeon specialization was associated with improved outcomes in perianal abscess. METHODS: Patients with perianal abscess admitted to the ASU between 2016 and 2020 were identified from a prospective database and their medical records reviewed. Patients with IBD, treatment for fistula-in-ano within the preceding year, or perianal sepsis of non-cryptoglandular origin were excluded. Patients admitted under an ASU colorectal (CR) consultant were compared with those under a non-CR general surgeon in a retrospective cohort study. Primary outcome was perianal abscess recurrence. For those without initial fistula, hazard of recurrent abscess or fistula was analysed. Multivariable Cox PH regression analysis was performed. RESULTS: Four-hundred and eight patients were included (150 CR, 258 non-CR). The CR group more frequently had a fistula identified at index operation (34.0% versus 10.9%, P < 0.0001). However, Cox multivariable analysis found no difference in hazard of recurrent abscess between groups (HR 1.12, 95% CI 0.65-1.95, P = 0.681)). Abscess recurred in 18.7% CR and 15.5% non-CR. Subsequent fistula developed in 14.7% in both groups. For patients without initial fistula, there was no difference between groups in hazard of recurrent abscess or fistula (HR 1.18, 95% CI 0.69-2.01, P = 0.539). CONCLUSION: Surgeon specialization was not associated with improved outcomes for ASU patients with perianal abscess, albeit with potential selection bias. CR surgeons were more proactive identifying fistulas; this raises the possibility that drainage alone may be adequate treatment.

Rare de novo gain-of-function missense variants in DOT1L are associated with developmental delay and congenital anomalies.

Misregulation of histone lysine methylation is associated with several human cancers and with human developmental disorders. DOT1L is an evolutionarily conserved gene encoding a lysine methyltransferase (KMT) that methylates histone 3 lysine-79 (H3K79) and was not previously associated with a Mendelian disease in OMIM. We have identified nine unrelated individuals with seven different de novo heterozygous missense variants in DOT1L through the Undiagnosed Disease Network (UDN), the SickKids Complex Care genomics project, and GeneMatcher. All probands had some degree of global developmental delay/intellectual disability, and most had one or more major congenital anomalies. To assess the pathogenicity of the DOT1L variants, functional studies were performed in Drosophila and human cells. The fruit fly DOT1L ortholog, grappa, is expressed in most cells including neurons in the central nervous system. The identified DOT1L variants behave as gain-of-function alleles in flies and lead to increased H3K79 methylation levels in flies and human cells. Our results show that human DOT1L and fly grappa are required for proper development and that de novo heterozygous variants in DOT1L are associated with a Mendelian disease.

Rare causes of abdominal pain: a primer for the admitting general surgeon.

The broad uptake of the acute surgical unit (ASU) model of surgical care in Australia has resulted in general surgeons becoming increasingly involved in the management of patients with acute abdominal pain (AAP), some of whom will be labelled as having non-specific abdominal pain (NSAP) (Kinnear N, Jolly S, Herath M, et al. The acute surgical unit: An updated systematic review and meta-analysis. review. Int. J. Surg. 2021;94:106109; Lehane CW, Jootun RN, Bennett M, Wong S, Truskett P. Does an acute care surgical model improve the management and outcome of acute cholecystitis? ANZ J. Surg. 2010;80:438-42). NSAP patients lack a clear diagnosis of surgical pathology based on standard clinical, laboratory and imaging work-up, although they may require ASU admission for pain control and assessment. This article provides a review of uncommon conditions, presenting as AAP, that could possibly be mis-labelled as NSAP, with a focus on aspects of the presentation that may aid diagnosis and management including specific demographic features, clinical findings, key investigations and initial treatment priorities for ASU clinicians. Ultimately, most of the conditions discussed will not require surgical intervention, however, they require a diagnosis to be made and initial treatment planning before on-referral to the appropriate specialty. For the on-call general surgeon, some knowledge of these conditions and an index of suspicion are invaluable for the prompt diagnosis and efficient management of these patients.

Use of Temporary Abdominal Closure in Non-Trauma Surgery: A Cohort Study.

BACKGROUND: Damage control surgery in trauma is widely used but the evidence for the use of laparostomy in non-trauma abdominal emergencies is limited. This study aimed to characterise outcomes in emergency abdominal surgery by comparing laparostomy to one-stage laparotomy for patients of similar illness severity. METHODS: A retrospective study of adult patients requiring emergency abdominal surgery and post-operative intensive care stay was performed between 2016 and 2020 at a major Australian metropolitan hospital. Case selection was from a prospectively maintained database, and case notes were reviewed. Patients having delayed abdominal closure were compared with those having one-stage abdominal closure. The primary outcome was odds of in-hospital mortality. The secondary outcomes included intensive care unit length of stay (LOS), overall hospital LOS, definitive stoma rate and discharge destination. Multivariable logistic regression analysis was performed to adjust for potentially confounding variables. RESULTS: Two hundred and eighteen patients met inclusion criteria (80 laparostomy and 138 non-laparostomy). The most common indications for laparostomy were bowel ischaemia (41.3%), sepsis (26.3%) and physiological instability (22.5%). There was no evidence of difference in odds of in-hospital mortality between groups (adjusted OR = 1.67, CI: 0.85-3.28; p = 0.138). Patients requiring laparostomy had a slightly longer median ICU LOS (4 vs. 3 days; p < 0.001), similar median hospital LOS (19 vs. 14 days, p = 0.245) and similar discharge destination. There was no difference in stoma rate (35.0% vs. 35.5%). CONCLUSION: Compared with standard one-stage laparotomy, laparostomy resulted in similar odds of in-hospital mortality in emergency abdominal surgery patients requiring intensive care.

Overall survival comparing laparoscopic to open surgery for right-sided colon cancer: propensity score inverse probability weighting population study.

BACKGROUND: This retrospective cohort study reports on overall survival and short-term complications, comparing laparoscopic to open resection for right-sided colon cancers. It is one of the largest studies in the field with generalizable population-level results. METHOD: This study on right sided colon cancers used prospectively collected administrative data linked to a death registry over 5 years from 2014 to 2018. Exclusion criteria were private patients, patients aged less than 10 years, synchronous and metachronous cancers. Propensity score weighting was used to balance cohorts and Cox proportional hazards regression was used to assess the hazard of death. In addition, logistic regression analysis was used to assess secondary outcomes. For completeness, unweighted data was similarly analysed. RESULTS: There were 3603 patients identified for the analysis: 1729 open patients and 1874 laparoscopic patients. Cox proportional hazards regression analysis of the weighted data showed no evidence of a statistically significant effect of laparoscopic surgery compared to open surgery on overall survival for right-sided colon cancers (HR 0.86, 95% CI 0.71-1.04, P = 0.112). The weighted data showed lower odds of prolonged length of stay, return to theatre and discharge destination other than home in the laparoscopic cohort compared to the open cohort. There was no difference in inpatient mortality. Unweighted results were similar. CONCLUSION: This study validates the use of laparoscopic surgery for right-sided colon cancer, showing similar long-term overall survival and inpatient mortality compared to open surgery. It is superior to open surgery for the short-term outcomes of LOS, return to theatre and discharge destination other than home.

Socioeconomic disadvantage and its impact on colorectal cancer in Australia: a scoping review.

BACKGROUND: Social disparities in cancer survival have been demonstrated in Australia despite a universal healthcare insurance system. Colorectal cancer is common, and reasons for survival disparities related to socioeconomic status need to be investigated and addressed. The aim is to evaluate the current Australian literature concerning the impact of socioeconomic status on colorectal cancer survival and stage at presentation. METHODS: A systematic search of PUBMED, EMBASE, SCOPUS and Clarivate Web of Science databases from January 2010 to March 2022 was performed. Studies investigating the impact of socioeconomic status on colorectal stage at presentation or survival in Australia were included. Data were extracted on author, year of publication, state or territory of origin, patient population, other exposure variables, outcomes and findings and adjustments made. RESULTS: Of the 14 articles included, the patient populations examined varied in size from 207 to 100 000+ cases. Evidence that socioeconomic disadvantage was associated with poorer survival was demonstrated in eight of 12 studies. Evidence of effect on late stage at presentation was demonstrated in two of seven studies. Area-level measures were commonly used to assess socioeconomic status, with varying indices utilized. CONCLUSION: There is limited evidence that socioeconomic status is associated with late-stage at presentation. More studies provide evidence of an association between socioeconomic disadvantage and poorer survival, especially larger studies utilizing less clinically-detailed cancer registry data. Further investigation is required to analyse why socioeconomic disadvantage may be associated with poorer survival.

T-stage downstaging of locally advanced rectal cancer after neoadjuvant chemoradiotherapy is not associated with reduced recurrence after adjusting for tumour characteristics.

BACKGROUND AND OBJECTIVES: Prior studies examining prognostic outcomes of locally advanced rectal adenocarcinomas achieving a complete pathological response following neoadjuvant chemoradiotherapy (nCRT) did not adjust for adverse prognostic factors in multivariate analyses and account for magnetic resonance imaging tumour staging inaccuracy pre-nCRT. We aimed to clarify prognostic outcomes in mT3 rectal adenocarcinomas with ypT-downstaging post-nCRT in robust adjusted analyses. METHODS: Retrospective analysis of prospectively-collected clinical data from 528 mT3 rectal adenocarcinomas ≤12 cm from the anal verge, any N-stage, no metastases, post-nCRT following total mesorectal excision (TME). Recurrence outcomes (local and distant combined) of tumours with complete ypT-downstaging (ypT0) post-nCRT before TME compared with no ypT-downstaging (≥ypT3) were examined using multivariate Cox regression, adjusting for confounders and accounting for pre-nCRT mT3-staging inaccuracy using bootstrapping. RESULTS: Complete ypT-downstaging was achieved in of 17.6% tumours and correlated strongly with complete pathological response. Complete ypT-downstaging was not associated with reduced recurrence hazards compared with no ypT-downstaging (hazard ratio = 0.60; 95% confidence interval [CI]: 0.23-1.56; p = 0.30). Lymphovascular invasion (LVI) and ypN+ve increased recurrence hazards by 1.8-fold (95% CI: 1.10-2.79; p = 0.02) and 2.3-fold (95% CI: 1.48-3.54; p = 0.0002), respectively. CONCLUSION: Complete ypT-downstaging was not associated with reduced recurrence after adjusting for confounders and accounting for mT3-staging inaccuracy, even in the absence of adverse prognostic factors (ypN+, LVI).

Is increasing nodal count associated with improved recurrence-free and overall survival following standard right hemicolectomy for colon cancer?

BACKGROUND AND OBJECTIVES: Increasing lymph node harvest for right-sided colon cancer is associated with improved overall survival (OS), but most relevant studies failed to report the extent of resection. We examined the association between increasing lymph node count with standard right hemicolectomy according to nodal status and prognostic outcomes in right-sided tumors. METHODS: Retrospective analysis of prospectively collected clinical data from patients with proximal colonic adenocarcinomas (n = 1390) following right hemicolectomy. Associations between lymph node counts (0-12 vs. 13-15, 16-20, and >20) and recurrence-free survival (RFS) and OS were examined using multivariate Cox modeling adjusted for confounders. RESULTS: We found no association between increasing nodal count and RFS, regardless of nodal status. In the absence of nodal metastases, increasing nodal count (16-20 and >20 vs. 0-12 nodes) was associated with 57% (95% confidence interval [CI]: 0.21-0.89) and 52% (95% CI: 0.24-0.95) improved OS, respectively. In the presence of nodal metastases, increasing nodal count was not associated with OS. Adjuvant chemotherapy did not modify this effect. CONCLUSION: Increasing nodal count (>15 nodes) with right hemicolectomy was not associated with improved RFS. Improved OS was only found for node-negative tumors, casting some doubt on the benefits of resecting more lymph nodes in the presence of nodal metastases.

Hospital Acquired Infections in Surgical Patients: Impact of COVID-19-Related Infection Prevention Measures.

BACKGROUND: Hospital acquired infections are common, costly, and potentially preventable adverse events. This study aimed to determine the effect of the COVID-19 pandemic-related escalation in infection prevention and control measures on the incidence of hospital acquired infection in surgical patients in a low COVID-19 environment in Australia. METHOD: This was a retrospective cohort study in a tertiary institution. All patients undergoing a surgical procedure from 1 April 2020 to 30 June 2020 (COVID-19 pandemic period) were compared to patients pre-pandemic (1 April 2019-30 June 2019). The primary outcome investigated was odds of overall hospital acquired infection. The secondary outcome was patterns of involved microorganisms. Univariable and multivariable logistic regression analysis was performed to assess odds of hospital acquired infection. RESULTS: There were 5945 admission episodes included in this study, 224 (6.6%) episodes had hospital acquired infections in 2019 and 179 (7.1%) in 2020. Univariable logistic regression analysis demonstrated no evidence of change in odds of having a hospital acquired infection between cohorts (OR 1.08, 95% CI 0.88-1.33, P = 0.434). The multivariable regression analysis adjusting for potentially confounding co-variables also demonstrated no evidence of change in odds of hospital acquired infection (OR 0.93, 95% CI 0.74-1.16, P = 0.530). CONCLUSION: Increased infection prevention and control measures did not affect the incidence of hospital acquired infection in surgical patients in our institution, suggesting that there may be a plateau effect with these measures in a system with a pre-existing high baseline of practice.

Colorectal cancer databases and registries in Australia: what data is available?

BACKGROUND: There are multiple data sources relating to colorectal cancer (CRC) nationwide. Prospective clinical cancer databases, population-based registries and linked administrative data are powerful tools in clinical outcomes research and provide real-world perspective on cancer treatments. This study aims to review the different Australian data sources for CRC from the perspective of conducting comparative research studies using a PICO (patient, intervention, comparison, outcome) framework. METHODS: Data dictionaries from the different data sources were evaluated for the types of exposure and outcome variables contained to highlight their differing research utility. RESULTS: State or territory-based cancer registries contain limited histology, cancer staging and treatment detail. They enable investigation of population-level patterns in overall survival (OS) of cancer patients with different demographics. Prospective clinical cancer databases contain more detail, especially surgical. Their strength is in auditing short-term surgical outcomes. They vary in the amount of data collected for other cancer treatments and completion of follow up data. Linked administrative databases have broad population coverage but less surgical detail. They provide population-level data on treatment patterns, short-term outcome measures and OS, as well as long-term surgical outcomes such as identifying patients who did not undergo stoma reversal. These databases cannot assess disease-free survival. CONCLUSION: Of the various CRC data sources within Australia, linked administrative databases have the potential to provide the widest population coverage combined with the broadest range of exposures and outcomes, and arguably the most research utility.

Survival benefit of neoadjuvant chemotherapy and surgery versus surgery first for resectable colorectal liver metastases: a cohort study.

BACKGROUND: There is continued debate about the survival benefit of neoadjuvant chemotherapy (neoCT) in patients with resectable colorectal liver metastases (CRLM). METHODS: In this retrospective cohort study, we included 201 patients with metastatic colorectal cancer who underwent their first CRLM resection and achieved resection of all sites of disease. We compared the overall survival (OS) and progression-free survival (PFS) between patients who received neoCT prior to CRLM resection with those who underwent CRLM upfront. A multivariable Cox proportional hazard regression analysis was performed to adjust for potential confounders. RESULTS: A total of 101 of 201 (51.2%) patients received chemotherapy prior to CRLM resection and 100 of 201 had surgery upfront. Multivariable Cox proportional hazard regression showed no statistically significant difference in the hazard of death for those given neoCT prior to resection of CRLM compared with surgery first for both OS and PFS (OS: hazard ratio 1.74, 95% confidence interval 0.85-3.55, P = 0.127, PFS: hazard ratio 1.42, 95% confidence interval 0.93-2.19, P = 0.107). CONCLUSION: In our series of patients with metastatic colorectal cancer who achieved surgical resection of all sites of disease, neoCT prior to CRLM resection was not associated with any survival benefit.

Impact of hospital geographic remoteness on overall survival after colorectal cancer resection using state-wide administrative data.

BACKGROUND: This study aimed to use administrative data (AD) linked to the Victorian death index (VDI) to report on overall long-term survival following colorectal cancer (CRC) surgery, comparing regional to metropolitan hospitals. METHODS: A retrospective cohort study using prospectively gathered AD linked to VDI. The primary outcome was overall survival (OS). Outcomes were adjusted for potential confounders via multivariable Cox proportional hazard regression analysis. RESULTS: Total of 17 533 patients: 12 879 metropolitan patients, 3835 inner regional patients and 719 outer regional patients. Multivariable Cox regression, adjusted for the effects of age, ASA score, Charlson score, position of tumour, mode of access, admission type, lymph node metastases, distant metastases, return to theatre, length of stay, HDU admission and discharge destination showed no difference in OS comparing CRC resection patients from inner or outer regional hospitals to metropolitan ((HR 1.02, 95% CI 0.95-1.09, P = 0.59) and (HR 0.97, 95% CI 0.85-1.11, P = 0.68) respectively). CONCLUSION: This is the largest and most detailed study concerning OS after CRC resection involving Victorian public hospitals. There was no difference in OS following CRC resection when inner or outer regional hospitals were compared to metropolitan hospitals in Victoria. The study demonstrated the utility of AD with validated algorithms, linked to death data for reporting CRC survival outcomes.