Publications by authors named "Karen Chiam"

Objective: To describe the patterns of care and factors associated with treatment uptake of localised prostate cancer, using the bi-national Prostate Cancer Outcomes Registry-Australia and New Zealand (PCOR-ANZ) database.

Methods: Data for 36 504 patients, diagnosed between 2015 and 2018, from New Zealand and seven Australian jurisdictions were evaluated. Multinomial logistic regression was performed to identify factors associated with the likelihood of receiving no active treatment, radiotherapy (RT), androgen deprivation therapy (ADT) and combined ADT + RT, compared to radical prostatectomy (RP).

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Objective: This study aimed to assess whether information from AI chatbots on benefits and harms of breast and prostate cancer screening were concordant with evidence-based cancer screening recommendations.

Methods: Seven unique prompts (four breast cancer; three prostate cancer) were presented to ChatGPT in March 2024. A total of 60 criteria (30 breast; 30 prostate) were used to assess the concordance of information.

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During the COVID-19 pandemic, countries adopted mitigation strategies to reduce disruptions to cancer services. We reviewed their implementation across health system functions and their impact on cancer diagnosis and care during the pandemic. A systematic search was performed using terms related to cancer and COVID-19.

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Information available from the New South Wales Cancer Registry (NSWCR) about the aggressiveness of prostate cancer is limited to the summary stage variable 'degree of spread', which contains a high proportion of cases defined as 'unknown'. In this study we demonstrate the feasibility of obtaining and analysing prostate cancer pathology data from stored pathology records. Pathology data were extracted from stored pathology records of incident prostate cancer cases in men participating in the 45 and Up Study, a large Australian prospective cohort study, who were diagnosed between January 2006 and December 2013.

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Guidelines for prostate specific antigen (PSA) testing in Australia recommend that men at average risk of prostate cancer who have been informed of the benefits and harms, and who decide to undergo regular testing, should be offered testing every 2 years from 50 to 69 years. This study aimed to estimate the benefits and harms of regular testing in this context. We constructed Policy1-Prostate, a discrete event microsimulation platform of the natural history of prostate cancer and prostate cancer survival, and PSA testing patterns and subsequent management in Australia.

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Article Synopsis
  • Prostate cancer (PC) risk factors were analyzed in a study involving over 107,000 men in Australia, examining data from health records and questionnaires.
  • Notable findings include increased PC risk with a family history of the disease, severe urinary symptoms, and previous vasectomy, while certain prescriptions for benign prostatic hyperplasia (BPH) and metformin appear to lower risk.
  • The study concludes that vasectomy and obesity increase the risk of advanced PC, while finding reduced risk linked to BPH and diabetes medications highlights the need for further research.
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Background: Population characteristics associated with the use of prostate biopsy are poorly understood. We described the use of diagnostic prostate biopsy and subsequent biopsy outcomes in a population-based Australian cohort.

Methods: A total of 91,764 men from the Sax Institute's 45 and Up Study (New South Wales, Australia) recruited during 2006 to 2009 were included.

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gene mutations occur in 70% of oesophageal adenocarcinomas (OACs). Given the central role of p53 in controlling cellular response to therapy we investigated the role of mutant (mut-) p53 and SLC7A11 in a CRISPR-mediated JH-EsoAd1 knockout model. Response to 2 Gy irradiation, cisplatin, 5-FU, 4-hydroxytamoxifen, and endoxifen was assessed, followed by a TaqMan OpenArray qPCR screening for differences in miRNA expression.

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Background: There is uncertainty on how multiparametric MRI (mpMRI) and MRI-targeted biopsy (MRI-TB) can be best used to manage low-risk prostate cancer patients on Active Surveillance (AS). We performed a scoping review to evaluate the benefits and harm associated with four different biopsy scenarios in which mpMRI can be implemented in AS.

Methods: Medline, Embase and Cochrane Library databases (1 January 2013-18 September 2020) were searched.

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Many patients with Oesophageal Adenocarcinoma (OAC) do not benefit from chemoradiotherapy treatment due to therapy resistance. To better understand the mechanisms involved in resistance and to find potential biomarkers, we investigated the association of microRNAs, which regulate gene expression, with the response to individual treatments, focusing on radiation. Intrinsic radiation resistance and chemotherapy drug resistance were assessed in eight OAC cell lines, and miRNA expression profiling was performed via TaqMan OpenArray qPCR.

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Background: Circulating microRNAs (miRNAs) are potential biomarkers for many diseases. However, they can originate from non-disease specific sources, such as blood cells, and compromise the investigations for miRNA biomarkers. While small extracellular vesicles (sEVs) have been suggested to provide a purer source of circulating miRNAs for biomarkers discovery, the most suitable blood sample for sEV miRNA biomarker studies has not been defined.

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A plethora of individual candidate biomarkers for predicting biochemical relapse in localized prostate cancer (PCa) have been proposed. Combined biomarkers may improve prognostication, and ensuring validation against more clinically relevant endpoints are required. The Australian PCa Research Centre NSW has contributed to numerous studies of molecular biomarkers associated with biochemical relapse.

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Background: Clinical trials report improved overall survival following neoadjuvant chemoradiotherapy in patients undergoing surgery for esophageal adenocarcinoma, with a 10-15% survival improvement. MicroRNAs (miRNAs) are small noncoding RNAs that are known to direct the behavior of cancers, including response to treatment. We investigated the ability of miRNAs to predict outcomes after neoadjuvant chemoradiotherapy.

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Background: The poor prognosis and rising incidence of esophageal adenocarcinoma highlight the need for improved detection methods. The potential for circulating microRNAs (miRNAs) as biomarkers in other cancers has been shown, but circulating miRNAs have not been well characterized in esophageal adenocarcinoma. We investigated whether circulating exosomal miRNAs have potential to discriminate individuals with esophageal adenocarcinoma from healthy controls and non-dysplastic Barrett's esophagus.

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Background: Phosphoinositide 3-kinase (PI3K)/Akt pathway is frequently activated in prostate carcinoma due to the loss of tumor suppressor PTEN, which leads to increased Akt activity. Expression of INPP4B, another negative regulator of the PI3K/Akt pathway, is also reduced in prostate carcinoma. However, uncertainty exists regarding the association of INPP4B expression and biochemical and clinical relapse of prostate carcinoma.

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Background: Krüppel-like factor (KLF) 6 is a candidate tumor suppressor gene in prostate cancer, but the mechanisms contributing to its loss of expression are poorly understood. We characterized KLF6 expression and DNA methylation status during prostate tumorigenesis in humans and mice.

Methods: KLF6 expression was assessed in matched human non-malignant (NM) and tumor prostate tissues (n = 22) by quantitative real-time PCR (qPCR) and in three independent human prostate cancer cohorts bioinformatically.

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Epigenome alterations are characteristic of nearly all human malignancies and include changes in DNA methylation, histone modifications and microRNAs (miRNAs). However, what induces these epigenetic alterations in cancer is largely unknown and their mechanistic role in prostate tumorigenesis is just beginning to be evaluated. Identification of the epigenetic modifications involved in the development and progression of prostate cancer will not only identify novel therapeutic targets but also prognostic and diagnostic markers.

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DNA methylation plays an important role in carcinogenesis and the reversibility of this epigenetic modification makes it a potential therapeutic target. To date, DNA methyltransferase inhibitors (DNMTi) have not demonstrated clinical efficacy in prostate cancer, with one of the major obstacles being the inability to monitor drug activity during the trial. Given the high frequency and specificity of GSTP1 DNA methylation in prostate cancer, we investigated whether GSTP1 is a useful marker of DNMTi treatment efficacy.

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Background: Epigenetic alterations are common in prostate cancer, yet how these modifications contribute to carcinogenesis is poorly understood. We investigated whether specific histone modifications are prognostic for prostate cancer relapse, and whether the expression of epigenetic genes is altered in prostate tumorigenesis.

Methods: Global levels of histone H3 lysine-18 acetylation (H3K18Ac) and histone H3 lysine-4 dimethylation (H3K4diMe) were assessed immunohistochemically in a prostate cancer cohort of 279 cases.

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There are numerous diseases associated with abnormal hormonal regulation and these include cancers of the breast and prostate. There is substantial evidence that early hormonal perturbations (in utero or during early development) are associated with increased disease susceptibility later in life. These perturbations may arise from exposure to environmental agents or endocrine disruptors which mimic hormones and disrupt normal hormonal signaling.

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