Sir Peter MacCallum Department of Oncology - Research Publications
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ItemNo Preview AvailableEarly circulating tumor DNA dynamics at the commencement of curative-intent radiotherapy or chemoradiotherapy for NSCLC(ELSEVIER IRELAND LTD, 2023-11)BACKGROUND: The kinetics of circulating tumor DNA (ctDNA) release following commencement of radiotherapy or chemoradiotherapy may reflect early tumour cell killing. We hypothesised that an increase in ctDNA may be observed after the first fraction of radiotherapy and that this could have clinical significance. MATERIALS AND METHODS: ctDNA analysis was performed as part of a prospective, observational clinical biomarker study of non-small cell lung cancer (NSCLC) patients, treated with curative-intent radiotherapy or chemoradiotherapy. Blood was collected at predefined intervals before, during (including 24 h after fraction 1 of radiotherapy) and after radiotherapy/chemoradiotherapy. Mutation-specific droplet digital PCR assays used to track ctDNA levels during and after treatment. RESULTS: Sequential ctDNA results are available for 14 patients with known tumor-based mutations, including in EGFR, KRAS and TP53, with a median follow-up of 723 days (range 152 to 1110). Treatments delivered were fractionated radiotherapy/chemoradiotherapy, in 2-2.75 Gy fractions (n = 12), or stereotactic ablative body radiotherapy (SABR, n = 2). An increase in ctDNA was observed after fraction 1 in 3/12 patients treated with fractionated radiotherapy with a complete set of results, including in 2 cases where ctDNA was initially undetectable. Neither SABR patient had detectable ctDNA immediately before or after radiotherapy, but one of these later relapsed systemically with a high detected ctDNA concentration. CONCLUSIONS: A rapid increase in ctDNA levels was observed after one fraction of fractionated radiotherapy in three cases. Further molecular characterization will be required to understand if a "spike" in ctDNA levels could represent rapid initial tumor cell destruction and could have clinical value as a surrogate for early treatment response and/or as a means of enriching ctDNA for mutational profiling.
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ItemNo Preview AvailableRisk-Directed Ambulatory Thromboprophylaxis in Lung and Gastrointestinal Cancers The TARGET-TP Randomized Clinical Trial(American Medical Association, 2023-11)IMPORTANCE: Thromboprophylaxis for individuals receiving systemic anticancer therapies has proven to be effective. Potential to maximize benefits relies on improved risk-directed strategies, but existing risk models underperform in cohorts with lung and gastrointestinal cancers. OBJECTIVE: To assess clinical benefits and safety of biomarker-driven thromboprophylaxis and to externally validate a biomarker thrombosis risk assessment model for individuals with lung and gastrointestinal cancers. DESIGN, SETTING, AND PARTICIPANTS: This open-label, phase 3 randomized clinical trial (Targeted Thromboprophylaxis in Ambulatory Patients Receiving Anticancer Therapies [TARGET-TP]) conducted from June 2018 to July 2021 (with 6-month primary follow-up) included adults aged 18 years or older commencing systemic anticancer therapies for lung or gastrointestinal cancers at 1 metropolitan and 4 regional hospitals in Australia. Thromboembolism risk assessment based on fibrinogen and d-dimer levels stratified individuals into low-risk (observation) and high-risk (randomized) cohorts. INTERVENTIONS: High-risk patients were randomized 1:1 to receive enoxaparin, 40 mg, subcutaneously daily for 90 days (extending up to 180 days according to ongoing risk) or no thromboprophylaxis (control). MAIN OUTCOMES AND MEASURES: The primary outcome was objectively confirmed thromboembolism at 180 days. Key secondary outcomes included bleeding, survival, and risk model validation. RESULTS: Of 782 eligible adults, 328 (42%) were enrolled in the trial (median age, 65 years [range, 30-88 years]; 176 male [54%]). Of these participants, 201 (61%) had gastrointestinal cancer, 127 (39%) had lung cancer, and 132 (40%) had metastatic disease; 200 (61%) were high risk (100 in each group), and 128 (39%) were low risk. In the high-risk cohort, thromboembolism occurred in 8 individuals randomized to enoxaparin (8%) and 23 control individuals (23%) (hazard ratio [HR], 0.31; 95% CI, 0.15-0.70; P = .005; number needed to treat, 6.7). Thromboembolism occurred in 10 low-risk individuals (8%) (high-risk control vs low risk: HR, 3.33; 95% CI, 1.58-6.99; P = .002). Risk model sensitivity was 70%, and specificity was 61%. The rate of major bleeding was low, occurring in 1 participant randomized to enoxaparin (1%), 2 in the high-risk control group (2%), and 3 in the low-risk group (2%) (P = .88). Six-month mortality was 13% in the enoxaparin group vs 26% in the high-risk control group (HR, 0.48; 95% CI, 0.24-0.93; P = .03) and 7% in the low-risk group (vs high-risk control: HR, 4.71; 95% CI, 2.13-10.42; P < .001). CONCLUSIONS AND RELEVANCE: In this randomized clinical trial of individuals with lung and gastrointestinal cancers who were stratified by risk score according to thrombosis risk, risk-directed thromboprophylaxis reduced thromboembolism with a desirable number needed to treat, without safety concerns, and with reduced mortality. Individuals at low risk avoided unnecessary intervention. The findings suggest that biomarker-driven, risk-directed primary thromboprophylaxis is an appropriate approach in this population. TRIAL REGISTRATION: ANZCTR Identifier: ACTRN12618000811202.
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ItemLarge variation in radiation therapy fractionation for multiple myeloma in Australia(WILEY, 2023-02)AIM: To evaluate the patterns of use of different radiation therapy (RT) fractionation for multiple myeloma (MM) bone disease. METHODS: This is a population-based cohort of patients with MM who had RT between 2012 and 2017 as captured in the statewide Victorian Radiotherapy Minimum Data Set in Australia. Data linkage was performed to identify subsets of RT delivered within 3 months of death. RT fractionation was classified into four groups: single-fraction (SFRT), 2-5, 6-10, and > 10 fractions. Changes in RT fractionation use over time were evaluated with the Cochran-Armitage test for trend. Factors associated with RT fractionation were evaluated using multivariate logistic regressions. RESULTS: Nine hundred and sixty-seven courses of RT were delivered in 623 patients. The proportion of SFRT, 2-5, 6-10 and > 10 fractions RT was 18%, 47%, 28%, and 7%, respectively. There was an increase in the use of 2-5 fractions, from 48% in 2012 to 60% in 2017 (p-trend < .001), with corresponding decrease in the use of 6-10 fractions, from 26% in 2012 to 20% in 2017 (p-trend = .003). Nine percent (40/430) of RT courses at private institutions were SFRT, compared to 25% (135/537) in public institutions (p < .001). In multivariate analyses, treatment in private institution was the strongest predictor of multifraction RT use. SFRT use was more common closer to the end of life-18%, 14%, and 33% of RT within 2-3, 1-2, < 1 month of death, respectively. CONCLUSION: There is increasing use of shorter course RT (2-5 fractions) for MM over time. SFRT use remains low, with large variation in practice.
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ItemImmunoPET: IMaging of cancer imMUNOtherapy targets with positron Emission Tomography: a phase 0/1 study characterising PD-L1 with 89Zr-durvalumab (MEDI4736) PET/CT in stage III NSCLC patients receiving chemoradiation study protocol.(BMJ Publishing Group, 2022-11-18)BACKGROUND: ImmunoPET is a multicentre, single arm, phase 0-1 study that aims to establish if 89Zr-durvalumab PET/CT can be used to interrogate the expression of PD-L1 in larger, multicentre clinical trials. METHODS: The phase 0 study recruited 5 PD-L1+ patients with metastatic non-small cell lung cancer (NSCLC). Patients received 60MBq/70 kg 89Zr-durva up to a maximum of 74 MBq, with scan acquisition at days 0, 1, 3 or 5±1 day. Data on (1) Percentage of injected 89Zr-durva dose found in organs of interest (2) Absorbed organ doses (µSv/MBq of administered 89Zr-durva) and (3) whole-body dose expressed as mSv/100MBq of administered dose was collected to characterise biodistribution.The phase 1 study will recruit 20 patients undergoing concurrent chemoradiotherapy for stage III NSCLC. Patients will have 89Zr-durva and FDG-PET/CT before, during and after chemoradiation. In order to establish the feasibility of 89Zr-durva PET/CT for larger multicentre trials, we will collect both imaging and toxicity data. Feasibility will be deemed to have been met if more than 80% of patients are able complete all trial requirements with no significant toxicity. ETHICS AND DISSEMINATION: This phase 0 study has ethics approval (HREC/65450/PMCC 20/100) and is registered on the Australian Clinical Trials Network (ACTRN12621000171819). The protocol, technical and clinical data will be disseminated by conference presentations and publications. Any modifications to the protocol will be formally documented by administrative letters and must be submitted to the approving HREC for review and approval. TRIAL REGISTRATION NUMBER: Australian Clinical Trials Network ACTRN12621000171819.
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ItemChanges in Apparent Diffusion Coefficient (ADC) in Serial Weekly MRI during Radiotherapy in Patients with Head and Neck Cancer: Results from the PREDICT-HN Study(MDPI, 2022-09)Background: The PREDICT-HN study aimed to systematically assess the kinetics of imaging MR biomarkers during head and neck radiotherapy. Methods: Patients with intact squamous cell carcinoma of the head and neck were enrolled. Pre-, during, and post-treatment MRI were obtained. Serial GTV and ADC measurements were recorded. The correlation between each feature and the GTV was calculated using Spearman’s correlation coefficient. The linear mixed model was used to evaluate the change in GTV over time. Results: A total of 41 patients completed the study. The majority (76%) had oropharyngeal cancer. A total of 36 patients had intact primary tumours that can be assessed on MRI, and 31 patients had nodal disease with 46 nodes assessed. Median primary GTV (GTVp) size was 14.1cc. The rate of GTVp shrinkage was highest between pre-treatment and week 4. Patients with T3-T4 tumours had a 3.8-fold decrease in GTVp compared to T1-T2 tumours. The ADC values correlated with residual GTVp. The median nodal volume (GTVn) was 12.4cc. No clinical features were found to correlate with GTVn reduction. The overall change in ADC for GTVn from pre-treatment was significant for 35th−95th percentiles in weeks 1−4 (p < 0.001). Conclusion: A discrepancy in the trajectory of ADC between primary and nodal sites suggested that they exhibit different treatment responses and should be analysed separately in future studies.
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ItemImaging immunity in patients with cancer using positron emission tomography(NATURE PORTFOLIO, 2022-04-07)Immune checkpoint inhibitors and related molecules can achieve tumour regression, and even prolonged survival, for a subset of cancer patients with an otherwise dire prognosis. However, it remains unclear why some patients respond to immunotherapy and others do not. PET imaging has the potential to characterise the spatial and temporal heterogeneity of both immunotherapy target molecules and the tumor immune microenvironment, suggesting a tantalising vision of personally-adapted immunomodulatory treatment regimens. Personalised combinations of immunotherapy with local therapies and other systemic therapies, would be informed by immune imaging and subsequently modified in accordance with therapeutically induced immune environmental changes. An ideal PET imaging biomarker would facilitate the choice of initial therapy and would permit sequential imaging in time-frames that could provide actionable information to guide subsequent therapy. Such imaging should provide either prognostic or predictive measures of responsiveness relevant to key immunotherapy types but, most importantly, guide key decisions on initiation, continuation, change or cessation of treatment to reduce the cost and morbidity of treatment while enhancing survival outcomes. We survey the current literature, focusing on clinically relevant immune checkpoint immunotherapies, for which novel PET tracers are being developed, and discuss what steps are needed to make this vision a reality.
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ItemBlood-Derived Extracellular Vesicle-Associated miR-3182 Detects Non-Small Cell Lung Cancer Patients(MDPI, 2022-01)With five-year survival rates as low as 3%, lung cancer is the most common cause of cancer-related mortality worldwide. The severity of the disease at presentation is accredited to the lack of early detection capacities, resulting in the reliance on low-throughput diagnostic measures, such as tissue biopsy and imaging. Interest in the development and use of liquid biopsies has risen, due to non-invasive sample collection, and the depth of information it can provide on a disease. Small extracellular vesicles (sEVs) as viable liquid biopsies are of particular interest due to their potential as cancer biomarkers. To validate the use of sEVs as cancer biomarkers, we characterised cancer sEVs using miRNA sequencing analysis. We found that miRNA-3182 was highly enriched in sEVs derived from the blood of patients with invasive breast carcinoma and NSCLC. The enrichment of sEV miR-3182 was confirmed in oncogenic, transformed lung cells in comparison to isogenic, untransformed lung cells. Most importantly, miR-3182 can successfully distinguish early-stage NSCLC patients from those with benign lung conditions. Therefore, miR-3182 provides potential to be used for the detection of NSCLC in blood samples, which could result in earlier therapy and thus improved outcomes and survival for patients.
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ItemA Deep Learning Model to Automate Skeletal Muscle Area Measurement on Computed Tomography Images(FRONTIERS MEDIA SA, 2021-05-07)BACKGROUND: Muscle wasting (Sarcopenia) is associated with poor outcomes in cancer patients. Early identification of sarcopenia can facilitate nutritional and exercise intervention. Cross-sectional skeletal muscle (SM) area at the third lumbar vertebra (L3) slice of a computed tomography (CT) image is increasingly used to assess body composition and calculate SM index (SMI), a validated surrogate marker for sarcopenia in cancer. Manual segmentation of SM requires multiple steps, which limits use in routine clinical practice. This project aims to develop an automatic method to segment L3 muscle in CT scans. METHODS: Attenuation correction CTs from full body PET-CT scans from patients enrolled in two prospective trials were used. The training set consisted of 66 non-small cell lung cancer (NSCLC) patients who underwent curative intent radiotherapy. An additional 42 NSCLC patients prescribed curative intent chemo-radiotherapy from a second trial were used for testing. Each patient had multiple CT scans taken at different time points prior to and post- treatment (147 CTs in the training and validation set and 116 CTs in the independent testing set). Skeletal muscle at L3 vertebra was manually segmented by two observers, according to the Alberta protocol to serve as ground truth labels. This included 40 images segmented by both observers to measure inter-observer variation. An ensemble of 2.5D fully convolutional neural networks (U-Nets) was used to perform the segmentation. The final layer of U-Net produced the binary classification of the pixels into muscle and non-muscle area. The model performance was calculated using Dice score and absolute percentage error (APE) in skeletal muscle area between manual and automated contours. RESULTS: We trained five 2.5D U-Nets using 5-fold cross validation and used them to predict the contours in the testing set. The model achieved a mean Dice score of 0.92 and an APE of 3.1% on the independent testing set. This was similar to inter-observer variation of 0.96 and 2.9% for mean Dice and APE respectively. We further quantified the performance of sarcopenia classification using computer generated skeletal muscle area. To meet a clinical diagnosis of sarcopenia based on Alberta protocol the model achieved a sensitivity of 84% and a specificity of 95%. CONCLUSIONS: This work demonstrates an automated method for accurate and reproducible segmentation of skeletal muscle area at L3. This is an efficient tool for large scale or routine computation of skeletal muscle area in cancer patients which may have applications on low quality CTs acquired as part of PET/CT studies for staging and surveillance of patients with cancer.
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ItemSingle-arm prospective interventional study assessing feasibility of using gallium-68 ventilation and perfusion PET/CT to avoid functional lung in patients with stage III non-small cell lung cancer(BMJ PUBLISHING GROUP, 2020)BACKGROUND: In the curative-intent treatment of locally advanced lung cancer, significant morbidity and mortality can result from thoracic radiation therapy. Symptomatic radiation pneumonitis occurs in one in three patients and can lead to radiation-induced fibrosis. Local failure occurs in one in three patients due to the lungs being a dose-limiting organ, conventionally restricting tumour doses to around 60 Gy. Functional lung imaging using positron emission tomography (PET)/CT provides a geographic map of regional lung function and preclinical studies suggest this enables personalised lung radiotherapy. This map of lung function can be integrated into Volumetric Modulated Arc Therapy (VMAT) radiotherapy planning systems, enabling conformal avoidance of highly functioning regions of lung, thereby facilitating increased doses to tumour while reducing normal tissue doses. METHODS AND ANALYSIS: This prospective interventional study will investigate the use of ventilation and perfusion PET/CT to identify highly functioning lung volumes and avoidance of these using VMAT planning. This single-arm trial will be conducted across two large public teaching hospitals in Australia. Twenty patients with stage III non-small cell lung cancer will be recruited. All patients enrolled will receive dose-escalated (69 Gy) functional avoidance radiation therapy. The primary endpoint is feasibility with this achieved if ≥15 out of 20 patients meet pre-defined feasibility criteria. Patients will be followed for 12 months post-treatment with serial imaging, biomarkers, toxicity assessment and quality of life assessment. DISCUSSION: Using advanced techniques such as VMAT functionally adapted radiation therapy may enable safe moderate dose escalation with an aim of improving local control and concurrently decreasing treatment related toxicity. If this technique is proven feasible, it will inform the design of a prospective randomised trial to assess the clinical benefits of functional lung avoidance radiation therapy. ETHICS AND DISSEMINATION: This study was approved by the Peter MacCallum Human Research Ethics Committee. All participants will provide written informed consent. Results will be disseminated via publications. TRIALS REGISTRATION NUMBER: NCT03569072; Pre-results.