Surgery (RMH) - Research Publications
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ItemTranscriptome sequencing and multi-plex imaging of prostate cancer microenvironment reveals a dominant role for monocytic cells in progression(BMC, 2021-07-22)BACKGROUND: Prostate cancer is caused by genomic aberrations in normal epithelial cells, however clinical translation of findings from analyses of cancer cells alone has been very limited. A deeper understanding of the tumour microenvironment is needed to identify the key drivers of disease progression and reveal novel therapeutic opportunities. RESULTS: In this study, the experimental enrichment of selected cell-types, the development of a Bayesian inference model for continuous differential transcript abundance, and multiplex immunohistochemistry permitted us to define the transcriptional landscape of the prostate cancer microenvironment along the disease progression axis. An important role of monocytes and macrophages in prostate cancer progression and disease recurrence was uncovered, supported by both transcriptional landscape findings and by differential tissue composition analyses. These findings were corroborated and validated by spatial analyses at the single-cell level using multiplex immunohistochemistry. CONCLUSIONS: This study advances our knowledge concerning the role of monocyte-derived recruitment in primary prostate cancer, and supports their key role in disease progression, patient survival and prostate microenvironment immune modulation.
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ItemLoss of SNAI2 in Prostate Cancer Correlates With Clinical Response to Androgen Deprivation Therapy(LIPPINCOTT WILLIAMS & WILKINS, 2021-06)PURPOSE: Androgen receptor (AR) signaling is important in prostate cancer progression, and therapies that target this pathway have been the mainstay of treatment for advanced disease for over 70 years. Tumors eventually progress despite castration through a number of well-characterized mechanisms; however, little is known about what determines the magnitude of response to short-term pathway inhibition. METHODS: We evaluated a novel combination of AR-targeting therapies (degarelix, abiraterone, and bicalutamide) and noted that the objective patient response to therapy was highly variable. To investigate what was driving treatment resistance in poorly responding patients, as a secondary outcome we comprehensively characterized pre- and post-treatment samples using both whole-genome and RNA sequencing. RESULTS: We find that resistance following short-term treatment differs molecularly from typical progressive castration-resistant disease, associated with transcriptional reprogramming, to a transitional epithelial-to-mesenchymal transition (EMT) phenotype rather than an upregulation of AR signaling. Unexpectedly, tolerance to therapy appears to be the default state, with treatment response correlating with the prevalence of tumor cells deficient for SNAI2, a key regulator of EMT reprogramming. CONCLUSION: We show that EMT characterizes acutely resistant prostate tumors and that deletion of SNAI2, a key transcriptional regulator of EMT, correlates with clinical response.
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ItemLate biochemical recurrence after radical prostatectomy is associated with a slower rate of progression(WILEY, 2019-06)OBJECTIVE: To characterise the pattern of late biochemical recurrence (BCR) in the largest contemporary cohort of patients with localised prostate cancer treated with radical prostatectomy (RP) in the active surveillance era. PATIENTS AND METHODS: Consecutive patients who underwent RP for localised prostate cancer between 2003 and 2017 were identified from a prospectively recorded, dedicated prostate cancer database. Patients who received neoadjuvant androgen-deprivation therapy were excluded. These patients were categorised into the following groups: no BCR, BCR at <12 months (early), BCR at 12-60 months (intermediate), and BCR at >60 months (late), after RP. Clinicopathological characteristics were analysed using the Student's t-test, Mann-Whitney U-test, or chi-squared test where appropriate. Multivariable binomial logistic regression models were used to assess predictors of BCR at various time-points. RESULTS: In all, 2312 patients were included in the final analysis with up to 12 years of follow-up data. The average patient had clinically localised prostate cancer, an elevated PSA level, and International Society of Urological Pathology (ISUP) Grade Group 2 on biopsy. In all, 88.7% of patients had ISUP Grade Group ≥2 at RP. A subgroup of 446 patients had undetectable PSA levels at 5 years after RP; 11.7% of them progressed to experience BCR. In this subgroup, late recurrers had significantly higher-grade tumours on ISUP and Gleason sum (P <0.001 and P = 0.001, respectively), higher rates of extraprostatic extension (P = 0.022), and larger tumour volumes (P = 0.032). Logistic regression showed that RP ISUP Grade Group was a significant predictor of BCR (odds ratio 2.14, 95% confidence interval 1.43-3.20; P <0.001). CONCLUSION: This study characterises the pattern of late BCR in the largest contemporary active surveillance era cohort. We have identified that RP ISUP Grade Group is a strong predictive indicator for late BCR. We also propose that timing of BCR resides on a continuum of risk and that the potential concept of dormant micrometastatic involvement requires further research and evaluation.
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ItemRobotic-assisted radical cystectomy with intracorporeal urinary diversion versus open: early Australian experience(WILEY, 2018-10)BACKGROUND: The aim of this study was to describe our initial Australian single surgeon experience with robotic-assisted radical cystectomy (RARC) and intracorporeal urinary diversion (ICUD) and to compare the outcomes with open radical cystectomy (ORC). METHODS: Between January 2014 and June 2016, consecutive patients diagnosed with muscle invasive and high-risk non-muscle invasive bladder cancer undergoing radical cystectomy were included. Treatment modalities included either RARC with ICUD or ORC. ICUD consisted of either intracorporeal ileal conduit or orthotopic neobladder formation. Prospectively collected perioperative and oncological outcomes were analysed. RESULTS: Twenty-six RARC and 13 ORC were performed. Median operating times were 362 and 240 min for RARC and ORC, respectively (P < 0.001). Estimated blood loss for RARC was 300 mL compared with 500 mL for ORC (P = 0.01). Post-operative haemoglobin drop was less in the RARC cohort (20% versus 24%, P = 0.03). There was no statistical difference in overall 90-day complication rates (81% versus 62%, P = 0.25) and 90-day major complication rates (19% versus 23%, P = 0.67) between the RARC and ORC groups, respectively. Positive surgical margins for RARC were 4% and 8% for ORC (P = 1.0). CONCLUSION: Early results demonstrate that the safe introduction of RARC with ICUD in Australia is potentially feasible without compromising perioperative and oncological outcomes. Future randomized trial with larger numbers will be required for further analysis in the Australian setting.
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ItemThe utility of magnetic resonance imaging in prostate cancer diagnosis in the Australian setting(WILEY, 2021-11)OBJECTIVES: To investigate the utility of Magnetic Resonance Imaging (MRI) for prostate cancer diagnosis in the Australian setting. PATIENTS AND METHODS: All consecutive men who underwent a prostate biopsy (transperineal or transrectal) at Royal Melbourne Hospital between July 2017 to June 2019 were included, totalling 332 patients. Data were retrospectively collected from patient records. For each individual patient, the risk of prostate cancer diagnosis at biopsy based on clinical findings was determined using the European Randomized study of Screening for Prostate Cancer (ERSPC) risk calculator, with and without incorporation of MRI findings. RESULTS: MRI has good diagnostic accuracy for clinically significant prostate cancer. A PI-RADS 2 or lower finding has a negative predictive value of 96% for clinically significant cancer, and a PI-RADS 3, 4 or 5 MRI scan has a sensitivity of 93%. However, MRI has a false negative rate of 6.5% overall for clinically significant prostate cancers. Pre- biopsy MRI may reduce the number of unnecessary biopsies, as up to 50.0% of negative or ISUP1 biopsies have MRI PI-RADS 2 or lower. Incorporation of MRI findings into the ERSPC calculator improved predictive performance for all prostate cancer diagnoses (AUC 0.77 vs 0.71, P = .04), but not for clinically significant cancer (AUC 0.89 vs 0.87, P = .37). CONCLUSION: MRI has good sensitivity and negative predictive value for clinically significant prostate cancers. It is useful as a pre-biopsy tool and can be used to significantly reduce the number of unnecessary prostate biopsies. However, MRI does not significantly improve risk predictions for clinically significant cancers when incorporated into the ERSPC risk calculator.