Surgery (RMH) - Research Publications
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ItemHow accurate are medical oncologists' impressions of management of metastatic colorectal cancer in Australia?(WILEY, 2018-04)AIM: Current efforts to understand patient management in clinical practice are largely based on clinician surveys with uncertain reliability. The TRACC (Treatment of Recurrent and Advanced Colorectal Cancer) database is a multisite registry collecting comprehensive treatment and outcome data on consecutive metastatic colorectal cancer (mCRC) patients at multiple sites across Australia. This study aims to determine the accuracy of oncologists' impressions of real-word practice by comparing clinicians' estimates to data captured by TRACC. METHODS: Nineteen medical oncologists from nine hospitals contributing data to TRACC completed a 34-question survey regarding their impression of the management and outcomes of mCRC at their own practice and other hospitals contributing to the database. Responses were then compared with TRACC data to determine how closely their impressions reflected actual practice. RESULTS: Data on 1300 patients with mCRC were available. Median clinician estimated frequency of KRAS testing within 6 months of diagnosis was 80% (range: 20-100%); the TRACC documented rate was 43%. Clinicians generally overestimated the rates of first-line treatment, particularly in patients over 75 years. Estimate for bevacizumab in first line was 60% (35-80%) versus 49% in TRACC. Estimated rate for liver resection varied substantially (5-35%), and the estimated median (27%) was inconsistent with the TRACC rate (12%). Oncologists generally felt their practice was similar to other hospitals. CONCLUSIONS: Oncologists' estimates of current clinical practice varied and were discordant with the TRACC database, often with a tendency to overestimate interventions. Clinician surveys alone do not reliably capture contemporary clinical practices in mCRC.
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ItemExamining the impact of regular aspirin use and PIK3CA mutations on survival in stage 2 colon cancer(WILEY, 2017-01)BACKGROUND/AIM: Data suggest aspirin improves survival in colorectal cancer (CRC) harbouring PIK3CA mutations. The impact of aspirin is thought predominantly to be through an anti-inflammatory effect. The aim of this study is to explore the effect of aspirin use on survival in a real-world cohort of stage 2 colon cancer (CC) patients. METHODS: A prospective CRC database identified patients diagnosed with stage 2 CC between 2000 and 2011. PIK3CA mutation status was determined by next generation sequencing. Neutrophil-lymphocyte ratio greater than 5 at diagnosis represented systemic inflammation. Chart review was used to record regular aspirin use at diagnosis. Clinico-pathological features and survival data were available. Survival analyses used the Cox proportional hazards method. RESULTS: Of 488 patients with stage 2 CC, 95 patients were aspirin users and 70 patients had PIK3CA mutations. Aspirin users were more likely to be older (median: 76.4 years vs 68.3 years, P < 0.001), to be less fit (American Society of Anaesthetists Score 3-4: 58% vs 31%, P < 0.001) and to have systemic inflammation (neutrophil-lymphocyte ratio > 5: 39% vs 27%, P = 0.027). Regular aspirin use did not significantly improve recurrence-free survival. In the PIK3CA mutated group, there was a trend towards improved recurrence-free survival (hazard ratio: 0.45, P = 0.42). CONCLUSIONS: Our study did not demonstrate a significant survival advantage from aspirin use in stage 2 PIK3CA mutated CC. The 'real-world' nature of our cohort and the subsequent uncontrolled differences in age and fitness in aspirin users are likely to have contributed to this result. Defining the true impact of aspirin in CRC requires prospective randomised clinical trials.
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ItemThe impact of bevacizumab in metastatic colorectal cancer with an intact primary tumor: Results from a large prospective cohort study(WILEY, 2017-08)BACKGROUND: Debate continues regarding the benefits versus risks of initial resection of the primary tumor in metastatic colorectal cancer (mCRC) patients with an asymptomatic primary tumor. Although the benefit of the anti-vascular endothelial growth factor agent bevacizumab alongside first-line chemotherapy in mCRC is established, the impact of bevacizumab on the intact primary tumor (IPT) is less well understood. METHODS: Data from an Australian mCRC registry were used to assess the impact of bevacizumab-based regimens in the presence of an IPT, to see if this differs from effects in resected primary tumor (RPT) patients and to understand the safety profile of bevacizumab in patients with IPT. Progression-free survival (PFS), overall survival (OS) and safety endpoints were analyzed. RESULTS: Of 1204 mCRC patients, 826 (69%) were eligible for inclusion. Bevacizumab use was similar in both arms (IPT (64%) versus RPT (70%)); compared with chemotherapy alone, bevacizumab use was associated with significantly longer PFS (IPT: 8.5 months vs 4.7 months, P = 0.017; RPT: 10.8 months vs 5.8 months, P < 0.001) and OS (IPT: 20 months vs 14.8 months, P = 0.005; RPT: 24.4 months vs 17.3 months, P = 0.004)).1 Bevacizumab use in an IPT was associated with more GI perforations (4.5% vs 1.8%, P = 0.210) but less frequent bleeding (1.5% vs 5.3%, P = 0.050) and thrombosis (1.5% vs 2.7%, P = 0.470), versus chemotherapy alone. Median survival was equivalent between patients that did or did not experience bevacizumab-related adverse events - 20.0 months versus 19.9 months, hazard ratio = 0.98, P = 0.623.1 CONCLUSIONS: The addition of bevacizumab significantly improved survival outcomes in mCRC with an IPT. The occurrence of bevacizumab-related adverse events did not significantly impact survival outcomes.
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ItemChemotherapy and biologic use in the routine management of metastatic colorectal cancer in Australia: is clinical practice following the evidence?(WILEY, 2019-04)BACKGROUND: Emerging evidence on the optimal use of chemotherapy and biologics in patients with metastatic colorectal cancer should impact management in routine care. Recent studies have demonstrated benefits for initial triplet chemotherapy (5-fluorouracil, oxaliplatin and irinotecan, FOLFOXIRI) and for initial treatment with an epidermal growth factor receptor inhibitor (EGFRi) in patients with a RAS wild-type tumour and a left-sided primary tumour. AIM: To explore evolving pattern of metastatic colorectal cancer care over time in Australia. METHODS: We analysed data from the Treatment of Recurrent and Advanced Colorectal Cancer registry. RESULTS: From July 2009 to December 2017, 2552 metastatic colorectal cancer patients were entered into the Treatment of Recurrent and Advanced Colorectal Cancer registry. Of 1585 patients who initially underwent chemotherapy, treatment was with a doublet in 76%. FOLFOXIRI was given to 22 patients (1.4%), mostly young patients and those with potentially resectable disease. Along with first-line chemotherapy, 61% received bevacizumab, while 3.3% received an EGFRi, predominantly over the last 2 years. Within the KRAS wild-type left-sided tumour cohort, EGFRi use increased from 9% in 2015 to 37% in 2017. Across treatment sites, there was a wide variation in the utilisation of FOLFOXIRI and EGFRi therapy; bevacizumab use was more consistent. A clear impact on survival outcomes from these regimens is not evident, potentially due to multiple confounders. CONCLUSION: Doublet chemotherapy + bevacizumab remains the dominant initial strategy, with limited uptake of triplet chemotherapy and of EGFRi. Potential explanations include uncertainty about the significance of post hoc analyses for EGFRi and concerns regarding adverse events for both strategies.
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ItemRight versus left sided metastatic colorectal cancer: Teasing out clinicopathologic drivers of disparity in survival(WILEY, 2019-06)BACKGROUND: Metastatic colorectal cancer (mCRC) patients with a right-sided primary (RC) have an inferior survival to mCRC arising from a left-sided primary (LC). Previous analyses have suggested multiple factors contribute. METHODS: The Treatment of Recurrent and Advanced Colorectal Cancer (TRACC) Registry prospectively captured data on consecutive mCRC patients. RC were defined as tumors proximal to the splenic flexure; LC were those at and distal to the splenic flexure and included rectal cancers. Patient, tumor, treatment, and survival data were analyzed stratified by side. RESULTS: Of 2306 patients enrolled from July 2009-March 2018, 747 (32%) had an RC. Patients with RC were older, more likely to be female and have a Charlson score ≥3. RC were more frequently BRAF mutated, deficient in mismatch repair, associated with peritoneal metastases, and less likely to receive chemotherapy. Progression-free survival on first-line systemic therapy was inferior for RC patients (8.1 vs. 10.8 months, hazard ratio [HR] for progression in RC 1.38, P < 0.001). Median overall survival for all RC patients was inferior (19.6 vs. 27.5 months, HR for death in RC 1.44, P < 0.001), and inferior within the treated (21 vs. 29.5 months, HR 1.52, P < 0.001) and untreated subgroups (5.9 vs. 10.3 months, HR 1.38, P = 0.009). Primary side remained a significant factor for overall survival in multivariate analysis. CONCLUSION: Our data from a real-world population confirms the poorer prognosis associated with RC. Primary tumor location remains significantly associated with overall survival even when adjusting for multiple factors, indicating the existence of further side-based differences that are as yet undefined.
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ItemInflammation, Biomarkers and Immuno-Oncology Pathways in Pancreatic Cancer(MDPI, 2019-06)It is estimated that pancreatic cancer will be the second leading cause of cancer-related deaths globally by 2030, highlighting the ongoing lack of effective treatment options for this devastating condition. There is a lack of reliable prognostic or predictive markers in pancreatic cancer to guide management decisions, whether for systemic chemotherapy, molecularly targeted therapies, or immunotherapies. To date, the results for targeted agents and immunotherapies in unselected populations of chemo-refractory pancreatic cancer have not met expectations. The reasons for this lack of efficacy of immunotherapy in pancreatic cancer are not completely understood. The challenges in pancreatic cancer include the physical barrier created by the dense desmoplastic stroma surrounding the tumor, chemokine-mediated exclusion of T cells, relatively poorer antigenicity compared to other solid tumors, paucity of infiltrating T cells within the tumor, ultimately leading to an immunosuppressive microenvironment. A better understanding of the role of inflammation in pancreatic cancer, its tumor microenvironment and individualized patient-related features, be they molecular, clinical or histopathological, would enable a more effective tailored approach to the management of pancreatic cancer. In this review, the role of inflammation, the immune tumor microenvironment and potential immune biomarkers in pancreatic cancer are explored.
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ItemClinical Applications of Circulating Tumour DNA in Pancreatic Adenocarcinoma(MDPI, 2019-09)Pancreatic adenocarcinoma remains one of the most aggressive cancers with an ongoing dismal survival rate despite some recent advances in treatment options. This is largely due to the typically late presentation and limited effective therapeutic options in advanced disease. There are numerous circulating biomarkers that have potential clinical application as tumour markers, including circulating tumour DNA (ctDNA), circulating tumour cells (CTCs), cell-free RNA (cfRNA), exosomes and circulating tumour proteins. This review will focus on the development of ctDNA as a non-invasive liquid biopsy, with its high sensitivity and specificity having potential clinical applications in pancreatic cancer. These include a role in screening, prognostication via the detection of minimal residual disease, early detection of recurrence, and for patients with advanced disease; tumour genotyping and monitoring treatment response. Prospective randomised adjuvant clinical trials are currently underway, exploring the impact of ctDNA-guided adjuvant therapy decisions. In this review, we provide perspectives on the current literature and considerations of future directions.