Surgery (Austin & Northern Health) - Research Publications

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    Clash of the calculators: External validation of prostate cancer risk calculators in men undergoing mpMRI and transperineal biopsy
    Wei, G ; Kelly, BD ; Timm, B ; Perera, M ; Lundon, DJ ; Jack, G ; Bolton, DM (WILEY, 2021-05)
    OBJECTIVE: To compare the accuracy of the European Randomized Study of Screening for Prostate Cancer (ERSPC) RC, MRI-ERSPC-RC, and Prostate Biopsy Collaborative Group (PBCG) RC in patients undergoing transperineal prostate biopsy. PATIENTS AND METHODS: We identified 392 patients who underwent mpMRI before transperineal prostate biopsy across multiple public and private institutions between January 2017 and August 2019. The estimated probabilities of detecting PCa and significant PCa were calculated using the MRI-ERSPC-RC, ERSPC-RC, and PBCG-RC. Receiver operating characteristic (ROC) curves for each calculator were generated and the area underneath the curve (AUC) was compared. Calibration and clinical utility were assessed with calibration plots and decision curve analysis, respectively. RESULTS: PCa was detected in 285 patients (72.7%) with significant PCa found in 200 patients (51.1%). ROC curve analysis found the MRI-ERSPC-RC outperformed the ERSPC-RC and PBCG-RC. For the prediction of PCa, the AUC was 0.756, 0.696, and 0.675 for the MRI-ERSPC-RC, ERSPC-RC, and PBCG-RC, respectively. The AUC for the prediction of significant PCa was 0.803, 0.745, and 0.746 for the MRI-ERSPC-RC, ERSPC-RC, and PBCG-RC, respectively. CONCLUSIONS: Our study validated the ERSPC-RC, MRI-ERSPC-RC, and PBCG-RC in a cohort undergoing transperineal prostate biopsy with the MRI-ERSPC-RC performing the best. These RCs may enable improved shared decision making and help to guide patient selection for biopsy.
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    Zinc supplementation as an adjunct therapy for COVID-19: Challenges and opportunities
    Chinni, V ; El-Khoury, J ; Perera, M ; Bellomo, R ; Jones, D ; Bolton, D ; Ischia, J ; Patel, O (WILEY, 2021-10)
    An outbreak of a novel coronavirus (COVID-19 or 2019-CoV) infection has posed significant threats to international health and the economy. Patients with COVID-19 are at risk of cytokine storm, acute respiratory distress syndrome (ARDS), reduced blood oxygenation, mechanical ventilation, and a high death rate. Although recent studies have shown remdesivir and dexamethasone as treatment options, there is an urgent need to find a treatment to inhibit virus replication and to control the progression of the disease. Essential biometal zinc has generated a lot of excitement as one of the promising candidates to reduce the severity of COVID-19 infection. Several published observations outlined in the review are the reasons why there is a global enthusiasm that zinc therapy could be a possible therapeutic option. However, the biggest challenge in realising the therapeutic value of zinc is lack of optimal treatment modalities such as dose, duration of zinc supplementation and the mode of delivery. In this review, we discuss the regulatory mechanism that hinges upon the bioavailability of zinc. Finally, we propose that intravenous zinc could circumvent the confounding factors affecting the bioavailability of zinc and allow zinc to achieve its therapeutic potential. If successful, due to advantages such as lack of toxicity, low cost and ease of availability, intravenous zinc could be rapidly implemented clinically.
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    A pilot double-blind safety and feasibility randomized controlled trial of high-dose intravenous zinc in hospitalized COVID-19 patients
    Patel, O ; Chinni, V ; El-Khoury, J ; Perera, M ; Neto, AS ; McDonald, C ; See, E ; Jones, D ; Bolton, D ; Bellomo, R ; Trubiano, J ; Ischia, J (WILEY, 2021-05)
    Zinc inhibits replication of the SARS-CoV virus. We aimed to evaluate the safety, feasibility, and biological effect of administering high-dose intravenous zinc (HDIVZn) to patients with COVID-19. We performed a Phase IIa double-blind, randomized controlled trial to compare HDIVZn to placebo in hospitalized patients with COVID-19. We administered trial treatment per day for a maximum of 7 days until either death or hospital discharge. We measured zinc concentration at baseline and during treatment and observed patients for any significant side effects. For eligible patients, we randomized and administered treatment to 33 adult participants to either HDIVZn (n = 15) or placebo (n = 18). We observed no serious adverse events throughout the study for a total of 94 HDIVZn administrations. However, three participants in the HDIVZn group reported infusion site irritation. Mean serum zinc on Day 1 in the placebo, and the HDIVZn group was 6.9 ± 1.1 and 7.7 ± 1.6 µmol/l, respectively, consistent with zinc deficiency. HDIVZn, but not placebo, increased serum zinc levels above the deficiency cutoff of 10.7 µmol/l (p < .001) on Day 6. Our study did not reach its target enrollment because stringent public health measures markedly reduced patient hospitalizations. Hospitalized COVID-19 patients demonstrated zinc deficiency. This can be corrected with HDIVZn. Such treatment appears safe, feasible, and only associated with minimal peripheral infusion site irritation. This pilot study justifies further investigation of this treatment in COVID-19 patients.
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    Zinc Preconditioning Provides Cytoprotection following Iodinated Contrast Media Exposure in In Vitro Models
    Perera, M ; Ischia, J ; Bolton, D ; Shulkes, A ; Baldwin, GS ; Patel, O ; de Barros, ALB (WILEY-HINDAWI, 2021-02-17)
    METHODS: Normal human proximal renal kidney cells (HK-2) were preconditioned with either increasing doses of ZnCl2 or control. Following this preconditioning, cells were exposed to increasing concentrations of Iohexol 300 mg I2/ml for four hours. Key outcome measures included cell survival (MTT colorimetric assay) and ROS generation (H2DCFDA fluorescence assay). RESULTS: Contrast media induced a dose-dependent reduction in survival of HK-2 cells. Compared to control, contrast media at 150, 225, and 300 mg I2/ml resulted in 69.5% (SD 8.8%), 37.3% (SD 4.8%), and 4.8% (SD 6.6%) cell survival, respectively (p < 0.001). Preconditioning with 37.5 μM and 50 μM ZnCl2 increased cell survival by 173% (SD 27.8%) (p < 0.001) and 219% (SD 32.2%) (p < 0.001), respectively, compared to control preconditioning. Zinc preconditioning resulted in a reduction of ROS generation. Zinc pre-conditioning with 37.5 μM μM ZnCl2 reduced ROS generation by 46% (p < 0.001) compared to control pre-conditioning. CONCLUSIONS: Zinc preconditioning reduces oxidative stress following exposure to radiographic contrast media which in turn results in increased survival of renal cells. Translation of this in vitro finding in animal models will lay the foundation for future use of zinc preconditioning against contrast induced nephropathy.
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    Changes in prescribing habits for the treatment of metastatic renal clear cell carcinoma (mRCC) in Australia
    Balasubramanian, A ; Qu, L ; Weickhardt, A ; Bolton, D ; Perera, M (WILEY, 2021-07)
    The availability of efficacious systemic therapies for metastatic clear cell renal cell carcinoma has heralded improved survival for Australians. The Pharmaceutical Benefits Schedule registry was interrogated to assess nation-wide prescribing patterns. Sunitinib remained the most commonly prescribed agent. Prescribing rates were significantly lower in Northern Territory than in other states, raising questions of disparities in access to care.
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    Patterns of primary staging for newly diagnosed prostate cancer in the era of prostate specific membrane antigen positron emission tomography: A population-based analysis
    Papa, N ; Perera, M ; Murphy, DG ; Lawrentschuk, N ; Evans, M ; Millar, JL ; Bolton, D (WILEY, 2021-10)
    INTRODUCTION: There has been a growing body of evidence highlighting the improved sensitivity and specificity for prostate specific membrane antigen (PSMA) positron emission tomography (PET) in advanced prostate cancer imaging. We aimed to assess prostate cancer staging practice patterns in Australia using population-based data. SUBJECT AND METHODS: We extracted data on men diagnosed with prostate cancer between October 2016 and December 2018 from the Prostate Cancer Outcomes Registry-Victoria (PCOR-Vic). We evaluated trends and comparisons between patients receiving PET/CT (with or without conventional imaging (CImg)), and CImg alone, and analysed imaging modality as predictor of clinical regional node positive disease (cN1 vs cN0/X), metastatic disease (cM1 vs cM0/X), and treatment received. RESULTS: In total, 6139 patients in the registry had either a staging PET scan (n = 889, 14%), CImg without PET scan (n = 2464, 40%), or no recorded PET or CImg (n = 2786, 45%). The proportion of allimaged patients who received staging PET increased from 19% to 36% from the first to last three-month period, and in the high-risk category the increase was 23-43%. After adjustment for grade group, PET vs CImg-only patients were observed to have a higher proportion of cN1 disease (OR = 2.46, 95% CI: 1.90-3.20) but not cM1 disease (OR = 1.10, 95% CI: 0.84-1.44). CONCLUSIONS: Our registry data highlights the rapid uptake of PET imaging, particularly in high-risk disease. Based on this data, we highlight the increased diagnosis of nodal disease, thus potentially optimizing patient selection prior to definitive treatment for prostate cancer.