Surgery (Austin & Northern Health) - Research Publications
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ItemComprehensive review of the use of hydrogel spacers prior to radiation therapy for prostate cancer(WILEY, 2023-03)OBJECTIVES: To provide a comprehensive narrative review of the published data on the impact of hydrogel spacers on rectal dosimetry and toxicity and to outline the practicalities of inserting hydrogel spacers. RESULTS: A growing body of evidence suggests that the administration of hydrogel spacers is safe and is associated with limited peri-operative morbidity. The impact on rectal dosimetry has been clearly established and use of hydrogel spacers is associated with reduced rectal morbidity. These results have been corroborated by several Phase II and III clinical trials and subsequent meta-analysis. There are several areas for future research, including the role of hydrogel spacers in prostate stereotactic beam radiotherapy and post-radiotherapy local recurrence. CONCLUSIONS: Hydrogel spacers provide a low-morbidity method to potential reduce rectal toxicity after radiation therapy in men with prostate cancer. Data outlining sexual function and oncological outcomes are limited to date. Future studies, currently being conducted, may provide further clarification of the role of hydrogel spacers in prostate cancer management.
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ItemDistant Nodes Seen on PSMA PET-CT Staging Predicts Post-Treatment Progression in Men with Newly Diagnosed Prostate Cancer-A Prospective Cohort Study(MDPI, 2022-12)PSMA PET-CT scans are now recommended in international urological guidelines for primary staging and re-staging of prostate cancer. However, there is little published literature on the clinical outcomes for patients after treatment decisions made using PSMA PET-CT results. This is a multisite, prospective cohort study investigating the clinical outcomes of men who received treatment plans based on PSMA PET-CT results for primary staging. Men with biopsy proven prostate cancer received a PSMA PET-CT scan for primary staging. Treatment plans were recommended by multidisciplinary teams (MDT). After treatment, these men were followed with 6 monthly PSA tests and imaging or biopsies if recommended by MDT. The primary outcome was treatment progression defined as the addition or change of any treatment modalities such as androgen deprivation therapy, radiation therapy or chemotherapy. In total, 80% of men did not have any treatment progression after enactment of treatment based on PSMA PET-CT primary staging results at 29 months of follow up. Men who had distant nodes seen on PSMA PET-CT had a 5 times increased risk of treatment progression. Larger studies with longer follow up are needed to validate our results and optimise the way clinicians use PSMA PET-CT results to guide management.
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ItemSocial Determinants Contribute to Disparities in Test Positivity, Morbidity and Mortality: Data from a Multi-Ethnic Cohort of 1094 GU Cancer Patients Undergoing Assessment for COVID-19(MDPI, 2022-09)Background: The COVID-19 pandemic exploits existing inequalities in the social determinants of health (SDOH) that influence disease burden and access to healthcare. The role of health behaviours and socioeconomic status in genitourinary (GU) malignancy has also been highlighted. Our aim was to evaluate predictors of patient-level and neighbourhood-level factors contributing to disparities in COVID-19 outcomes in GU cancer patients. Methods: Demographic information and co-morbidities for patients screened for COVID-19 across the Mount Sinai Health System (MSHS) up to 10 June 2020 were included. Descriptive analyses and ensemble feature selection were performed to describe the relationships between these predictors and the outcomes of positive SARS-CoV-2 RT-PCR test, COVID-19-related hospitalisation, intubation and death. Results: Out of 47,379 tested individuals, 1094 had a history of GU cancer diagnosis; of these, 192 tested positive for SARS-CoV-2. Ensemble feature selection identified social determinants including zip code, race/ethnicity, age, smoking status and English as the preferred first language—being the majority of significant predictors for each of this study’s four COVID-19-related outcomes: a positive test, hospitalisation, intubation and death. Patient and neighbourhood level SDOH including zip code/ NYC borough, age, race/ethnicity, smoking status, and English as preferred language are amongst the most significant predictors of these clinically relevant outcomes for COVID-19 patients. Conclusion: Our results highlight the importance of these SDOH and the need to integrate SDOH in patient electronic medical records (EMR) with the goal to identify at-risk groups. This study’s results have implications for COVID-19 research priorities, public health goals, and policy implementations.
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ItemRole of PSMA PET-guided metastases-directed therapy in oligometastatic recurrent prostate cancer(FRONTIERS MEDIA SA, 2022-08-18)Oligometastatic prostate cancer (OMPC) has been proposed as an intermediary state between localised disease and widespread metastases, with varying definitions including 1, 3, or ≤5 visceral or bone metastasis. Traditional definitions of OMPC are based on staging with conventional imaging, such as computerised tomography (CT) and whole-body bone scan (WBBS). Novel imaging modalities such as prostate-specific membrane antigen positron emission tomography (PSMA PET) have improved diagnostic utility in detecting early metastatic prostate cancer (PC) metastases compared with conventional imaging. Specifically, meta-analytical data suggest that PSMA PET is sensitive in detecting oligometastatic disease in patients with biochemical recurrence (BCR) post-radical treatment of PC. Recent trials have evaluated PSMA PET-guided metastases-directed therapy (MDT) in oligometastatic recurrent disease, typically with salvage surgery or radiotherapy (RT). To date, these preliminary studies demonstrate promising results, potentially delaying the need for systemic therapy. We aim to report a comprehensive, multidisciplinary review of PSMA-guided MDT in OMPC. In this review, we highlight the utility of PMSA PET in biochemically recurrent disease and impact of PSMA PET on the definition of oligometastatic disease and outline data pertaining to PSMA-guided MDT.
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ItemPEDAL protocol: a prospective single-arm paired comparison of multiparametric MRI and 18F-DCPFyl PSMA PET/CT to diagnose prostate cancer(BMJ PUBLISHING GROUP, 2022-09)INTRODUCTION: Prostate-specific membrane antigen positron emission tomography (PSMA-PET) has emerged as valuable imaging to assessing metastatic disease in prostate malignancy. However, there has been limited studies exploring the utility PSMA-PET as primary imaging assessing for index lesions prior to biopsy. The primary objective of this study is to compare the diagnostic accuracy of 18-fluorine PSMA (18F DCFPyL PSMA) PET scans to multiparametric MRI (mpMRI) to detect primary prostate cancer at prostate biopsy. METHODS AND ANALYSIS: The PEDAL trial is a multicentre, prospective, single-arm, paired comparison, non-randomised phase III trial in subjects considered for diagnostic prostate biopsy. Subjects who are eligible for a diagnostic mpMRI prostate will undergo additional same-day 18 F DCFPyl PSMA PET/CT of the chest, abdomen and pelvis. Software coregistration of the mpMRI and PSMA-PET/CT images will be performed. The reporting of the mpMRI prostate, PSMA-PET/CT and PSMA PET/MRI coregistration will be performed blinded. The diagnostic accuracy of PSMA PET/CT alone, and in combination with mpMRI, to detect prostate cancer will be assessed. Histopathology at prostate biopsy will be used as the reference standard. Sample size calculations estimate that 240 subjects will need to be recruited to demonstrate 20% superiority of PSMA-PET/CT. The sensitivity, specificity, positive predictive value and negative predictive value of the combination of mpMRI prostate and PSMA PET/CT compared with targeted and systematic prostate biopsy will be evaluated. It is hypothesised that PSMA PET/CT combined with mpMRI prostate will have improved diagnostic accuracy compared with mpMRI prostate alone for detection of prostate cancer in biopsy-naïve men, resulting in a significant impact on patient management. ETHICS AND DISSEMINATION: This study was approved by the independent Human Research Ethics Committee. Results will be published in peer-reviewed medical journals with eligible investigators will significantly contribute. TRIAL REGISTRATION NUMBER: ACTRN12620000261910.
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ItemContributions to expenditure in endoscopic stone management: a costly process(SPRINGER, 2022-10)No comprehensive cost estimates exist for performing ureteropyeloscopy (URS), which is increasingly utilised as a treatment of upper tract urolithiasis in Australia. To estimate expenditure associated with URS in an Australian public hospital setting and determine factors contributing to increased cost. Patients who underwent flexible URS for urolithiasis over a 2-year period at a Victorian public health site were included. Data describing demographics, stone factors, disposable equipment and admission length were retrospectively collected. Procedures were performed using reusable flexible scopes. Previously validated costing models for cystoscopic stent extraction, theatre and recovery per hour and ward admission were used to attach cost to individual episodes. The cost of emergency stent insertion was beyond the scope of this study. 222 patients underwent URS; the combined total number of procedures was 539, comprising 202 stent extractions and 115 stent insertions in addition to 222 URS. Mean procedural cost was $2885 (range $1380-$4900). Mean episode cost excluding emergency stent insertion was $3510 (range $1555-$7140). A combination of flexible scopes, operative time and disposable equipment accounted for nearly 90% of the total procedural cost. Significant cost is associated with URS for treatment of renal and ureteric stones. A large burden of the cost is time in theatre, equipment and the need for multiple associated procedures per episode. Utilising other available treatments such as extracorporeal shockwave therapy (SWL) where appropriate may reduce the financial burden of URS and associated procedures.
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ItemNovel Germline Mutations in a Cohort of Men with Familial Prostate Cancer(MDPI, 2022-08)Background: Germline mutations in BRCA2 are associated with aggressive prostate cancer. Additional information regarding the clinical phenotype of germline pathogenic variants in other prostate cancer predisposition genes is required. Clinical testing has been limited by evidence, further restricting knowledge of variants that contribute to prostate cancer development. Objective: Prostate cancer patients who were first- and second-degree relatives from multi-case prostate cancer families underwent a gene panel screen to identify novel (non-BRCA) germline pathogenic variants in cancer predisposition genes and define clinical phenotypes associated with each gene. Methods: The germline genomic DNA (gDNA) of 94 index cases with verified prostate cancer from families with a minimum of two verified prostate cancer cases was screened with an 84-cancer-gene panel. Families were recruited for multi-case breast/ovarian cancer (n = 66), or multi-case prostate cancer (n = 28). Prostate cancer characteristics associated with each gene were compared with prostate cancer cases of confirmed non-mutation carriers (BRCAX), also from multi-case prostate cancer families (n = 111), and with data from the Prostate Cancer Outcomes Registry (PCOR). Results: Ninety-four prostate cancer index cases underwent gene panel testing; twenty-two index cases (22/94; 23%) were found to carry a class 4-5 (C4/5) variant. Six of twenty-two (27%) variants were not clinically notifiable, and seven of twenty-two (31.8%) variants were in BRCA1/2 genes. Nine of twenty-two (40.9%) index cases had variants identified in ATM (n = 4), CHEK2 (n = 2) and HOXB13G84 (n = 3); gDNA for all relatives of these nine cases was screened for the corresponding familial variant. The final cohort comprised 15 confirmed germline mutation carriers with prostate cancer (ATM n = 9, CHEK2 n = 2, HOXB13G84 n = 4). ATM and CHEK2-associated cancers were D'Amico intermediate or high risk, comparable to our previously published BRCA2 and BRCAX prostate cancer cohort. HOXB13G84 carriers demonstrated low- to intermediate-risk prostate cancer. In the BRCAX cohort, 53.2% of subjects demonstrated high-risk disease compared with 25% of the PCOR cohort. Conclusions:ATM and CHEK2 germline mutation carriers and the BRCAX (confirmed non-mutation carriers) cohort demonstrated high risk disease compared with the general population. Targeted genetic testing will help identify men at greater risk of prostate-cancer-specific mortality. Data correlating rare variants with clinical phenotype and familial predisposition will strengthen the clinical validity and utility of these results and establish these variants as significant in prostate cancer detection and management.
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ItemTumor immune microenvironment of primary prostate cancer with and without germline mutations in homologous recombination repair genes(BMJ PUBLISHING GROUP, 2022-06)BACKGROUND: Aberrations in homologous recombination repair (HRR) genes are emerging as important biomarkers for personalized treatment in prostate cancer (PCa). HRR deficiency (HRD) could affect the tumor immune microenvironment (TIME), potentially contributing to differential responses to poly ADP-ribose polymerase (PARP) inhibitors and immune checkpoint inhibitors. Spatial distribution of immune cells in a range of cancers identifies novel disease subtypes and is related to prognosis. In this study we aimed to determine the differences in the TIME of PCa with and without germline (g) HRR mutations. METHODS: We performed gene expression analysis, multiplex immunohistochemistry of T and B cells and quantitative spatial analysis of PCa samples from 36 patients with gHRD and 26 patients with sporadic PCa. Samples were archival tumor tissue from radical prostatectomies with the exception of one biopsy. Results were validated in several independent cohorts. RESULTS: Although the composition of the T cell and B cells was similar in the tumor areas of gHRD-mutated and sporadic tumors, the spatial profiles differed between these cohorts. We describe two T-cell spatial profiles across primary PCa, a clustered immune spatial (CIS) profile characterized by dense clusters of CD4+ T cells closely interacting with PD-L1+ cells, and a free immune spatial (FIS) profile of CD8+ cells in close proximity to tumor cells. gHRD tumors had a more T-cell inflamed microenvironment than sporadic tumors. The CIS profile was mainly observed in sporadic tumors, whereas a FIS profile was enriched in gHRD tumors. A FIS profile was associated with lower Gleason scores, smaller tumors and longer time to biochemical recurrence and metastasis. CONCLUSIONS: gHRD-mutated tumors have a distinct immune microenvironment compared with sporadic tumors. Spatial profiling of T-cells provides additional information beyond T-cell density and is associated with time to biochemical recurrence, time to metastasis, tumor size and Gleason scores.