Sir Peter MacCallum Department of Oncology - Research Publications
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ItemIntraductal carcinoma of the prostate can evade androgen deprivation, with emergence of castrate-tolerant cells(WILEY, 2018-06)OBJECTIVE: To determine the relevance of intraductal carcinoma of the prostate (IDC-P) in advanced prostate cancer by first examining whether IDC-P was originally present in patients who later developed advanced prostate cancer and then using patient-derived xenografts (PDXs) to investigate the response of IDC-P to androgen deprivation therapy (ADT). MATERIALS AND METHODS: We conducted a retrospective pathology review of IDC-P in primary prostate biopsy or surgery specimens from 38 men who subsequently developed advanced prostate cancer. Overall survival was calculated using the Kaplan-Meier method. To demonstrate the response of IDC-P to ADT, we established PDXs from seven patients with familial and/or high-risk sporadic prostate cancer. After castration and testosterone restoration of host mice, we measured the volume and proliferation of IDC-P within PDX grafts. RESULTS: We found that IDC-P was a prominent feature in the primary prostate specimens, present in 63% of specimens and often co-existing with poorly differentiated adenocarcinoma. Overall survival was similar in patients with or without IDC-P. In the PDXs from all seven patients, IDC-P was identified and present at a similar volume to adenocarcinoma. Residual IDC-P lesions persisted after host castration and, similar to castrate-tolerant adenocarcinoma, testosterone restoration led to tumour regeneration. CONCLUSION: The study showed that IDC-P is prevalent in aggressive prostate cancer and contains cells that can withstand androgen deprivation. Thus, IDC-P appears functionally relevant in advanced prostate cancer. The presence of IDC-P may be a trigger to develop innovative clinical management plans.
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ItemDistress and unmet needs during treatment and quality of life in early cancer survivorship: A longitudinal study of haematological cancer patients(WILEY, 2017-11)OBJECTIVE: To examine the influence of anxiety, depression and unmet supportive care needs on future quality of life (QoL) in multiple myeloma (MM) and diffuse large B-cell lymphoma (DLBCL) patients. METHODS: Multiple myeloma and DLBCL patients recruited through the population-based Victorian Cancer Registry. Data were collected through two telephone interviews: (T1) on average 7 months postdiagnosis, (T2) average 8 months later. QoL was examined at T2 using the Functional Assessment of Cancer Therapy (FACT-G) scale. The Hospital Anxiety and Depression Scale measured anxiety and depression, and the Supportive Care Needs Survey measured unmet needs at T1. Multivariate linear regression examined associations between QoL subscales (physical, emotional, social and functional well-being and overall QoL) and T1 anxiety, depression and unmet needs. RESULTS: Except physical well-being, all other QoL subscales and overall QoL were significantly associated with T1 anxiety. All QoL subscales and overall QoL were significantly associated with T1 depression. Only patient care needs were associated with physical and social well-being and overall QoL. CONCLUSION: Anxiety, depression and patient care unmet needs during treatment are associated with diminished physical and emotional well-being in the following months. Psychological distress and unmet supportive care needs experienced during treatment should be addressed to maximise future QoL.
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ItemTrends in the surgical management of stage 1 renal cell carcinoma: findings from a population-based study(WILEY, 2017-11)OBJECTIVES: To determine whether the use of nephron-sparing surgery (NSS) for treatment of stage 1 renal cell carcinoma (RCC) changed between 2009 and the end of 2013 in Australia. PATIENTS AND METHODS: All adult cases of RCC diagnosed in 2009, 2012 and 2013 were identified through the population-based Victorian Cancer Registry. For each identified patient, trained data-abstractors attended treating hospitals or clinician rooms to extract tumour and treatment data through medical record review. Multivariable logistic regression analyses were carried out to examine the significance of change in use of NSS over time, after adjusting for potential confounders. RESULTS: A total of 1 836 patients with RCC were identified. Of these, the proportion of cases with stage 1 tumours was 64% in 2009, 66% in 2012 and 69% in 2013. For T1a tumours, the proportion of patients residing in metropolitan areas receiving NSS increased from 43% in 2009 to 58% in 2012 (P < 0.05), and 69% in 2013 (P < 0.05). For patients residing in non-metropolitan areas, the proportion receiving NSS increased from 27% in 2009 to 49% in 2012, and 61% in 2013 (P < 0.01). Univariable logistic regression showed patients with moderate (odds ratio [OR] 0.57, 95% confidence interval [CI] 0.35-0.94) or severe comorbidities (OR 0.58, 95% CI 0.33-0.99), residing in non-metropolitan areas (OR 0.65, 95% CI 0.47-0.90), were less likely to be treated by NSS, while those attending high-volume hospitals (≥30 cases/year: OR 1.79, 95% CI 1.21-2.65) and those with higher socio-economic status (OR 1.45, 95% CI 1.02-2.07) were more likely to be treated by NSS. In multivariable analyses, patients with T1a tumours in 2012 (OR 2.00, 95% CI 1.34-2.97) and 2013 (OR 3.15, 95% CI 2.13-4.68) were more likely to be treated by NSS than those in 2009. For T1b tumours, use of NSS increased from 8% in 2009 to 20% in 2013 (P < 0.05). CONCLUSION: This population-based study of the management of T1 renal tumours in Australia found that the use of NSS increased over the period 2009 to 2013. Between 2009 and 2013 clinical practice for the treatment of small renal tumours in Australia has increasingly conformed to international guidelines.
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ItemMetformin may offer no protective effect in men undergoing external beam radiation therapy for prostate cancer(WILEY, 2019-05)OBJECTIVES: To assess whether metformin reduces radio-resistance and increases survival in men undergoing external beam radiation therapy (EBRT) for prostate cancer (PCa), and to determine its effect on hypoxia inducible factor 1-α (HIF1α). PATIENTS AND METHODS: All patients treated with curative intent with EBRT for PCa at a major cancer centre between 2000 and 2007 were included in this study. The outcome measures of time to biochemical failure (BF), metastasis, PCa-specific mortality and overall survival (OS) were analysed in those taking metformin vs those not, using competing risk and Cox regression models. To determine metformin's effect on HIF1α expression and survival in vitro, PC3 cells with high basal HIF1α levels were subjected to increasing doses of metformin after H2 O2 -induced oxidative stress. RESULTS: A total of 2055 eligible cases, including 113 who were on metformin, were identified, with a median follow-up of 95.7 months. There were no differences in age, initial prostate-specific antigen level, Gleason score, T-stage, D'Amico risk class or duration of androgen deprivation therapy (ADT) between patients who were or were not on metformin. Treatment with metformin did not result in any apparent improvement in time to BF, time to metastasis detection or OS, but there was a 1.5-fold increase in PCa-specific deaths (P = 0.045) in patients on metformin and ADT when adjusted for cancer risk and comorbidities. When comparing patients on high-dose metformin (>1 g/d) with those on low-dose metformin (≤1 g), there was no difference in either time to metastases or time to BF. In vitro metformin at a high concentration of 100 μM did not reduce HIF1α expression, nor did metformin affect the PC3 cell survival when exposed to oxidative stress (H2 O2 ). CONCLUSIONS: No association was found between the use of metformin and time to metastasis detection, time to BF or OS in patients undergoing radiation therapy with or without ADT for PCa. In vitro, low therapeutic concentrations of metformin had no effect on HIF1α, and this observation could explain the conflicting evidence for the effectiveness of metformin in men undergoing EBRT for PCa. Higher, more toxic doses of metformin may be required to inhibit the mammalian target of rapamycin-HIF1α pathway in this patient group.
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ItemGermline BRCA2 mutations drive prostate cancers with distinct evolutionary trajectories(NATURE PUBLISHING GROUP, 2017-01-09)Germline mutations in the BRCA2 tumour suppressor are associated with both an increased lifetime risk of developing prostate cancer (PCa) and increased risk of aggressive disease. To understand this aggression, here we profile the genomes and methylomes of localized PCa from 14 carriers of deleterious germline BRCA2 mutations (BRCA2-mutant PCa). We show that BRCA2-mutant PCa harbour increased genomic instability and a mutational profile that more closely resembles metastastic than localized disease. BRCA2-mutant PCa shows genomic and epigenomic dysregulation of the MED12L/MED12 axis, which is frequently dysregulated in metastatic castration-resistant prostate cancer (mCRPC). This dysregulation is enriched in BRCA2-mutant PCa harbouring intraductal carcinoma (IDC). Microdissection and sequencing of IDC and juxtaposed adjacent non-IDC invasive carcinoma in 10 patients demonstrates a common ancestor to both histopathologies. Overall we show that localized castration-sensitive BRCA2-mutant tumours are uniquely aggressive, due to de novo aberration in genes usually associated with metastatic disease, justifying aggressive initial treatment.