Surgery (Austin & Northern Health) - Research Publications
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ItemCaptopril, a Renin-Angiotensin System Inhibitor, Attenuates Features of Tumor Invasion and Down-Regulates C-Myc Expression in a Mouse Model of Colorectal Cancer Liver Metastasis(MDPI, 2021-06)(1) Background: Recent clinical and experimental data suggests that the liver's regenerative response following partial hepatectomy can stimulate tumor recurrence in the liver remnant. The Wnt/β-catenin pathway plays important roles in both colorectal cancer carcinogenesis and liver regeneration. Studies have shown that the Wnt/β-catenin pathway regulates multiple renin-angiotensin system (RAS) genes, whilst RAS inhibition (RASi) reduces tumor burden and progression. This study explores whether RASi attenuates features of tumor progression in the regenerating liver post-hepatectomy by modulating Wnt/β-catenin signaling. (2) Methods: Male CBA mice underwent CRLM induction, followed one week later by 70% partial hepatectomy. Mice were treated daily with captopril, a RASi, at 250 mg/kg/day or vehicle control from experimental Day 4. Tumor and liver samples were analyzed for RAS and Wnt signaling markers using qRT-PCR and immunohistochemistry. (3) Results: Treatment with captopril reduced the expression of down-stream Wnt target genes, including a significant reduction in both c-myc and cyclin-D1, despite activating Wnt signaling. This was a tumor-specific response that was not elicited in corresponding liver samples. (4) Conclusions: We report for the first time decreased c-myc expression in colorectal tumors following RASi treatment in vivo. Decreased c-myc expression was accompanied by an attenuated invasive phenotype, despite increased Wnt signaling.
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ItemTargeting DNA Damage Response and Replication Stress in Pancreatic Cancer(W B SAUNDERS CO-ELSEVIER INC, 2021-01)BACKGROUND & AIMS: Continuing recalcitrance to therapy cements pancreatic cancer (PC) as the most lethal malignancy, which is set to become the second leading cause of cancer death in our society. The study aim was to investigate the association between DNA damage response (DDR), replication stress, and novel therapeutic response in PC to develop a biomarker-driven therapeutic strategy targeting DDR and replication stress in PC. METHODS: We interrogated the transcriptome, genome, proteome, and functional characteristics of 61 novel PC patient-derived cell lines to define novel therapeutic strategies targeting DDR and replication stress. Validation was done in patient-derived xenografts and human PC organoids. RESULTS: Patient-derived cell lines faithfully recapitulate the epithelial component of pancreatic tumors, including previously described molecular subtypes. Biomarkers of DDR deficiency, including a novel signature of homologous recombination deficiency, cosegregates with response to platinum (P < .001) and PARP inhibitor therapy (P < .001) in vitro and in vivo. We generated a novel signature of replication stress that predicts response to ATR (P < .018) and WEE1 inhibitor (P < .029) treatment in both cell lines and human PC organoids. Replication stress was enriched in the squamous subtype of PC (P < .001) but was not associated with DDR deficiency. CONCLUSIONS: Replication stress and DDR deficiency are independent of each other, creating opportunities for therapy in DDR-proficient PC and after platinum therapy.
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ItemPopulation-based analysis of treatment patterns and outcomes for pancreas cancer in Victoria(WILEY, 2020-09)BACKGROUND: The Victorian Pancreas Cancer summit 2017 analysed state-wide data on management of Victorians with pancreas cancer between 2011 and 2015 to identify variations in care and outcomes. Pancreas cancer remains a formidable disease but systemic therapies are increasingly effective. Surgery remains essential but insufficient alone for cure. Understanding patterns of care and identifying variations in treatment is critical to improving outcomes. METHODS: This population-based study analysed data collected prospectively by Department of Health and Human services (Victorian state government). Data were extracted from Victorian Cancer Registry (covering all Victorian cancer diagnoses), Victorian Admitted-Episodes Dataset (all inpatient data), Victorian Radiotherapy Minimum Dataset and Victorian Death Index providing demographics, tumour and treatment characteristics, age-standardized incidence, overall and median survival. RESULTS: Of 3962 Victorian patients with any form of pancreatic malignancy, 82% were ductal adenocarcinoma (PDAC), of whom 67% had metastases at diagnosis. One-year overall survival for PDAC was 30% (60% non-metastatic, 15% if metastatic). Median survival with metastases increased from 2.7 to 3.9 months, and from 13.3 to 15.9 months for non-metastatic PDAC between 2011 and 2015. Thirty-one percent of non-metastatic patients underwent pancreatectomy. About 1.5% were treated with neoadjuvant chemotherapy/chemoradiation. Of patients undergoing intended curative resection, 77% proceeded to adjuvant therapy. Fifty-one percent of metastatic PDAC patients never received anti-tumour therapy. CONCLUSIONS: Nearly one-fourth of surgically treated patients never received systemic therapy. More than two-thirds of non-metastatic patients never proceeded to surgery. Further consideration of neoadjuvant therapy should be given to borderline resectable patients. Most patients with PDAC still die soon after diagnosis, but median survival is increasing.
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ItemHealth costs of post-operative complications following rectal resection: a systematic review(WILEY, 2020-07)BACKGROUND: Post-operative complications following rectal resection pose significant health and cost implications for patients and health providers. The objective of this study is to review the associated cost of complications following rectal resection. This included reporting on the proportion and severity of these complications, associated length of stay and surgical technique used. Studies were sourced from Embase OVID, MEDLINE OVID (ALL) and Cochrane Library databases by utilizing a search strategy. METHODS: This search contained studies from 1 January 2010 until 13 February 2019. Studies were included from the year 2010 to account for the implementation of enhanced recovery after surgery protocols. Studies that reported the financial cost associated with complications were included. Any indication for rectal resection was considered. Data was extracted into a formatted table and a narrative synthesis was performed. RESULTS: We identified 13 eligible studies for inclusion. There was strong evidence to suggest that complications are associated with increased costs. There was considerable variation as to the costs attributable to complications ($1443 (P < 0.001) to $17 831 (P < 0.0012), n = 12). The presence of complications was associated with an increased length of stay (5.54 (P-value not given) to 21.04 (P < 0.0001) days, n = 7). There was significant variation in the proportion of complications (6.41 to 64.71%, n = 8). Weak evidence existed around surgical technique used and the associated cost of complications. There was considerable heterogeneity among included studies. CONCLUSIONS: Complications following rectal resection increased health costs. Costs should be standardized and provide a clear methodology for their calculation. Complications should be standardized and include a grading of severity.
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ItemOutcomes of inguinal hernia repair in cirrhotics: a single tertiary centre experience(WILEY, 2020-05)BACKGROUND: Patients with liver cirrhosis are at a higher risk of perioperative anaesthetic and surgical complications. Surgical repair of abdominal wall hernias in these patients has been widely discouraged. The main objective of this study was to evaluate the post-operative outcomes of patients with liver cirrhosis after inguinal hernia repair at a single institution. METHODS: A retrospective review of a prospectively maintained database of 31 patients with liver cirrhosis undergoing inguinal hernia repair between 2006 and 2016 was undertaken. Data in relation to patient demographics, clinicopathological characteristics, morbidity and mortality were collected. RESULTS: Thirty-one patients with median Model for End-stage Liver Disease score of 14 (7-36) underwent inguinal hernia repair within a 10-year period of our study. There was one mortality in a patient with Model for End-stage Liver Disease score of 36 who presented with a strangulated hernia. Only one patient required return to theatre for the evacuation of haematoma and one patient developed a recurrent hernia in 1-year follow up. CONCLUSION: Inguinal hernia repair in patients with cirrhosis is a safe procedure to perform in the elective setting. Nevertheless, significant consideration must be given in performing these operations in centres with liver transplant units due to their extensive experience in pre-operative optimization to reduce the risk of hepatic decompensation.
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ItemWhat makes an article impactful?(WILEY, 2020-01)
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ItemProcurement-related liver injury for transplantation: an analysis of the risk factors and consequences in an Australian transplant centre(WILEY, 2021-12)BACKGROUND: Liver transplantation is an established treatment for liver failure, and its success relies on the quality of the donated organ amongst other factors. Studies on procurement-related liver injury (PRLI) are few and some may not apply to modern-day practice. This is the first Australian study examining risk factors and consequences of PRLI. METHOD: The Victorian Liver Transplant Unit database was examined for deceased liver donors from 2010 to 2017. Information regarding the donor, retrieval and subsequent transplantation was obtained. PRLI details were sought from the 'organ retrieval report form'. PRLI risk factors and their complications were analysed. RESULTS: A total of 420 transplants were included, with 45 injuries in 44 livers (10%), and significant injuries were observed in 4%. Variant anatomy was associated with an increased risk of PRLI (11% vs. 2%, p < 0.001). Complication rates were not significantly different between livers with and without PRLI however a reduction in early graft survival was observed. CONCLUSION: This study shows that PRLI is common, and that variant anatomy is associated with an increased risk of injury. Appropriate feedback and benchmarking are important to maintain a high quality in donor surgery.
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ItemThe financial burden of complications following rectal resection A cohort study(Lippincott, Williams & Wilkins, 2020-05-01)To investigate the costs associated with postoperative complications following rectal resection. Rectal resection is a major surgical procedure that carries a significant risk of complications. The occurrence of complications following surgery has both health and financial consequences. There are very few studies that examine the incidence and severity of complications and their financial implications following rectal resection. We identified 381 consecutive patients who underwent a rectal resection within a major university hospital. Patients were included using the International Classification of Diseases (ICD) codes. Complications in the postoperative period were reported using the validated Clavien-Dindo classification system. Both the number and severity of complications were recorded. Activity-based costing methodology was used to report financial outcomes. Preoperative results were also recorded and assessed. A 76.9% [95% CI: 68.3:86.2] of patients experienced one or more complications. Patients who had a complication had a median total cost of $22,567 [IQR 16,607:33,641]. Patients who did not have a complication had a median total cost of $15,882 [IQR 12,971:19,861]. The adjusted additional median cost for patients who had a complication was $5308 [95% CI: 2938:7678] (P < .001). Patients who experienced a complication tended to undergo an open procedure (P = .001), were emergent patients (P = .003), preoperatively had lower albumin levels (36 vs 38, P = .0003) and were anemic (P = .001). Complications following rectal resection are common and are associated with increased costs. Our study highlights the importance of evaluating and preventing complications in the postoperative period.
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ItemImmunomodulatory effects of renin-angiotensin system inhibitors on T lymphocytes in mice with colorectal liver metastases(BMJ PUBLISHING GROUP, 2020)BACKGROUND: It is now recognized that many anticancer treatments positively modulate the antitumor immune response. Clinical and experimental studies have shown that inhibitors of the classical renin-angiotensin system (RAS) reduce tumor progression and are associated with better outcomes in patients with colorectal cancer. RAS components are expressed by most immune cells and adult hematopoietic cells, thus are potential targets for modulating tumor-infiltrating immune cells and can provide a mechanism of tumor control by the renin-angiotensin system inhibitors (RASi). AIM: To investigate the effects of the RASi captopril on tumor T lymphocyte distribution in a mouse model of colorectal liver metastases. METHODS: Liver metastases were established in a mouse model using an autologous colorectal cancer cell line. RASi (captopril 750 mg/kg) or carrier (saline) was administered to the mice daily via intraperitoneal injection, from day 1 post-tumor induction to endpoint (day 15 or 21 post-tumor induction). At the endpoint, tumor growth was determined, and lymphocyte infiltration and composition in the tumor and liver tissues were analyzed by flow cytometry and immunohistochemistry (IHC). RESULTS: Captopril significantly decreased tumor viability and impaired metastatic growth. Analysis of infiltrating T cells into liver parenchyma and tumor tissues by IHC and flow cytometry showed that captopril significantly increased the infiltration of CD3+ T cells into both tissues at day 15 following tumor induction. Phenotypical analysis of CD45+ CD3+ T cells indicated that the major contributing phenotype to this influx is a CD4 and CD8 double-negative T cell (DNT) subtype, while CD4+ T cells decreased and CD8+ T cells remained unchanged. Captopril treatment also increased the expression of checkpoint receptor PD-1 on CD8+and DNT subsets . CONCLUSION: Captopril treatment modulates the immune response by increasing the infiltration and altering the phenotypical composition of T lymphocytes and may be a contributing mechanism for tumor control.
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ItemThe hospital costs of complications following colonic resection surgery: A retrospective cohort study(ELSEVIER SCI LTD, 2020-06)BACKGROUND: Colonic resection is a common surgical procedure associated with a high rate of postoperative complications. The aim of this observational study is to estimate the in-hospital costs of complications and to identify perioperative variables associated with complication development following colon resection surgery. MATERIALS AND METHODS: We conducted a single-centre cohort study with retrospective data collection of 487 patients undergoing colonic resection surgery between 2013 and 2018. Postoperative complications were graded according to the Clavien-Dindo classification system. In-hospital cost of index admission is reported in 2019 United States Dollars. Regression modelling was used to investigate the relationship of a priori selected perioperative variables and presence of complications and costs. RESULTS: Overall complication prevalence was 69.6% (95%CI:65.5%-73.7%). Median [interquartile range] cost of patients with postoperative complications was significantly increased as compared to patients without complications ($17,963 [13,533:25,178] vs $12,578 [10,196:16,140]; p < 0.0001). Clavien-Dindo Grade I, II, III and IV complications increased costs by 15.8%, 36.8%, 169.4% and 240.1% respectively (p < 0.0001). Presence of complications was significantly associated with Charlson Comorbidity Index (Odds ratio (OR) per 1-unit increase: 1.09; 95%CI:1.02 to 1.17), preoperative albumin levels (OR per 1-unit increase: 0.94; 95%CI:0.90 to 0.98) and open as compared to laparoscopic resection (OR: 2.41; 95%CI:1.32 to 4.42). CONCLUSIONS: There is a high prevalence of complications following colonic resection surgery. Postoperative complications, including minor complications (Clavien-Dindo Grade I-II), were associated with a significant increase in hospital costs and are a key target for cost containment strategies.