Sir Peter MacCallum Department of Oncology - Research Publications
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ItemThe therapeutic relevance of a BRCA2 mutation in a patient with recurrent thymoma: a case report.(AME Publishing Company, 2022)BACKGROUND: Thymomas are characterized by a low tumor mutation burden and a paucity of actionable mutations. Clinical behavior can vary from relatively indolent to very aggressive and impact survival. Platinum-based chemotherapy is the primary treatment modality for inoperable disease and is palliative in intent. Patients with advanced thymoma frequently experience disease recurrence after frontline therapy. Treatment options for relapsed thymoma are relatively limited. A case of recurrent thymoma harboring a breast cancer gene 2 (BRCA2) mutation was presented for multidisciplinary discussion at the International Thymic Malignancy Interest Group (ITMIG) Tumor Board meeting. CASE DESCRIPTION: A 63-year-old female presented with Tumor Node Metastasis (TNM) stage I, World Health Organization (WHO) subtype B1 thymoma at diagnosis and underwent surgical resection. First recurrence occurred in the left costophrenic recess and was treated with preoperative external beam radiotherapy (EBRT), surgical excision, and post-operative chemotherapy. Histology was consistent with WHO subtype B2 thymoma and genomic analysis of the resected tumor detected a BRCA2 mutation. Second recurrence occurred in the mediastinum and bilateral pleurae. Mediastinal disease was treated with EBRT, and the pleural deposits were observed initially. However, upon further progression, the case was discussed at the ITMIG tumor board meeting to determine optimal second line therapy for this patient. CONCLUSIONS: A potential role of poly (ADP-ribose) polymerase (PARP) inhibitors versus cytotoxic chemotherapy for treatment of BRCA2-mutated recurrent thymoma merits discussion. However, due to the absence of data to support the functional and therapeutic significance of BRCA2 mutations in patients with thymoma, the potential for severe toxicity associated with PARP inhibitors, and availability of other safe and effective alternatives, other treatment options should be considered. PARP inhibitors can be considered for treatment of BRCA2-mutated thymomas as part of a clinical trial or when other treatment options have been exhausted.
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ItemPredicting muscle loss during lung cancer treatment (PREDICT): protocol for a mixed methods prospective study(BMJ PUBLISHING GROUP, 2021-09)INTRODUCTION: Low muscle mass and low muscle attenuation (radiodensity), reflecting increased muscle adiposity, are prevalent muscle abnormalities in people with lung cancer receiving curative intent chemoradiation therapy (CRT) or radiation therapy (RT). Currently, there is a limited understanding of the magnitude, determinants and clinical significance of these muscle abnormalities in the lung cancer CRT/RT population. The primary objective of this study is to identify the predictors of muscle abnormalities (low muscle mass and muscle attenuation) and their depletion over time in people with lung cancer receiving CRT/RT. Secondary objectives are to assess the magnitude of change in these parameters and their association with health-related quality of life, treatment completion, toxicities and survival. METHODS AND ANALYSIS: Patients diagnosed with lung cancer and planned for treatment with CRT/RT are invited to participate in this prospective observational study, with a target of 120 participants. The impact and predictors of muscle abnormalities (assessed via CT at the third lumbar vertebra) prior to and 2 months post CRT/RT on the severity of treatment toxicities, treatment completion and survival will be assessed by examining the following variables: demographic and clinical factors, weight loss, malnutrition, muscle strength, physical performance, energy and protein intake, physical activity and sedentary time, risk of sarcopenia (Strength, Assistance in walking, Rise from a chair, Climb stairs, Falls history (SARC-F) score alone and with calf-circumference) and systemic inflammation. A sample of purposively selected participants with muscle abnormalities will be invited to take part in semistructured interviews to understand their ability to cope with treatment and explore preference for treatment strategies focused on nutrition and exercise. ETHICS AND DISSEMINATION: The PREDICT study received ethics approval from the Human Research Ethics Committee at Peter MacCallum Cancer Centre (HREC/53147/PMCC-2019) and Deakin University (2019-320). Findings will be disseminated through peer review publications and conference presentations.
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ItemControversies in the role of radiotherapy in pleural mesothelioma(AME PUBLISHING COMPANY, 2021-04)Malignant pleural mesothelioma is an uncommon thoracic cancer with a relatively poor outcome, which has only seen modest improvements when compared to non-small cell lung cancer. The mainstays of treatment have been surgery and systemic therapy, with radiation reserved for palliation or as an adjunct. However, there is re-emergent interest in the use of radiotherapy in the treatment of mesothelioma, given recent technical advances in radiotherapy delivery which permit increased treatment accuracy. This overview article reviews the radiobiology of the mesothelioma and whether or not mesothelioma is an inherently radioresistant cancer and the potential impact that hypofractionation may have on different histological subtypes in mesothelioma. This overview also considers the role of radiation in palliation, as adjunct to surgical resection and as adjunct to pleural tract procedures. In particular we review the growing evidence that pleural tract or port site adjuvant radiotherapy provides no clinical benefit. This overview will also consider potential emerging therapeutic strategies such as pre-operative short course hypofractionated radiotherapy. The role of novel radiotherapy techniques such as stereotactic ablative radiotherapy, image guided radiotherapy, proton therapy and the potential role of radiotherapy as an immune stimulating agent in combination of immunotherapy, will also be discussed. Finally, given the many unanswered questions, this review discusses some of the emerging and ongoing clinical trials of radiotherapy in the treatment of mesothelioma.
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ItemImpact of COVID-19 on cancer service delivery: a follow-up international survey of oncology clinicians(ELSEVIER, 2020-10)BACKGROUND: The COVID-19 pandemic has had a vast impact on cancer service delivery around the world. Previously reported results from our international survey of oncology clinicians, conducted through March-April 2020, found that clinicians reported altering management in both the curative and palliative settings and not in proportion to the COVID-19 case burden in their region of practice. This follow-up survey, conducted from 27th September to 7th November 2020, aimed to explore how attitudes and practices evolved over the 2020 pandemic period. PARTICIPANTS AND METHODS: Participants were medical, radiation and surgical oncologist and trainees. Surveys were distributed electronically via ESMO and other collaborating professional societies. Participants were asked to compare their practice prior to the pandemic to both the period of March-April 2020, referred to as the 'early' period, and the current survey period, referred to as the 'later' period. RESULTS: One hundred and seventy-two oncology clinicians completed the survey. The majority of respondents were medical oncologists (n = 136, 79%) and many were from Europe (n = 82, 48%). In the 'early' period, 88% (n = 133) of clinicians reported altering their practice compared to 63% (n = 96) in the 'later' period. Compared to prior to the pandemic, clinicians reported fewer new patient presentations in the 'early' period and a trend towards more patients presenting with advanced disease in the 'later' period. CONCLUSIONS: Results indicate a swing back towards pre-COVID-19 practices despite an increase in the rate of cumulative COVID-19 cases across 2020. The impact of these changes on cancer associated morbidity and mortality remains to be measured over the months and years to come.
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ItemLung organ-at-risk volumes: A survey of practice and the need for a consistent definition in the 4DCT era(WILEY, 2020-02)INTRODUCTION: In the 4DCT era, the definition of lung organ-at-risk (OAR) volumes for dose-volume histogram (DVH) calculation is unclear, introducing potential for variability in practice. We aimed to identify definitions used clinically and evaluate the magnitude of DVH differences between these. METHODS: We surveyed Australian & New Zealand departments about lung radiotherapy protocols including lung OAR volume definition. We used these definitions to calculate lung DVHs on 10 patients prescribed lung IMRT (60-66 Gy/30-33 fractions). We calculated mean lung dose (MLD), V20 and V30 for 'Lungs - PTV', 'Lungs - CTV', 'Lungs - iGTV' (internal GTV in all respiratory phases) and 'Lungs - GTV_EX' (expiratory phase). RESULTS: The response rate was 39% (34/88). 14% and 29% of departments did not have a departmental protocol for OAR and tumour volume delineation, respectively. All permutations for lung OAR volumes were used with no clear preference. For conventional radiotherapy (n = 27), this included Lungs alone (n = 1), Lungs - PTV (n = 6), Lungs - CTV (n = 2), Lungs - iGTV (n = 6), Lungs - GTV in single phase (n = 5) and individual clinician preference (n = 7). The different lung OAR volumes resulted in MLD difference ranging from 0.9 to 4.15 Gy, V20 from 1.5% to 6.6% and V30 from 1.34% to 7.11%. The largest differences between subtraction of GTV_EX and iGTV were 0.32 Gy, 0.43% and 0.46% for MLD, V20 and V30, respectively. CONCLUSION: A significant number of departments lacked lung cancer radiotherapy contouring protocols. Lung OAR volume definition was variable between and within departments. Potentially clinically significant differences in lung DVH parameters were seen according to the volume used.
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ItemNo Preview AvailableAn International Expert Survey on the Indications and Practice of Radical Thoracic Reirradiation for Non-Small Cell Lung Cancer(ELSEVIER INC, 2021)PURPOSE: Thoracic reirradiation for non-small cell lung cancer with curative intent is potentially associated with severe toxicity. There are limited prospective data on the best method to deliver this treatment. We sought to develop expert consensus guidance on the safe practice of treating non-small cell lung cancer with radiation therapy in the setting of prior thoracic irradiation. METHODS AND MATERIALS: Twenty-one thoracic radiation oncologists were invited to participate in an international Delphi consensus process. Guideline statements were developed and refined during 4 rounds on the definition of reirradiation, selection of appropriate patients, pretreatment assessments, planning of radiation therapy, and cumulative dose constraints. Consensus was achieved once ≥75% of respondents agreed with a statement. Statements that did not reach consensus in the initial survey rounds were revised based on respondents' comments and re-presented in subsequent rounds. RESULTS: Fifteen radiation oncologists participated in the 4 surveys between September 2019 and March 2020. The first 3 rounds had a 100% response rate, and the final round was completed by 93% of participants. Thirty-three out of 77 statements across all rounds achieved consensus. Key recommendations are as follows: (1) appropriate patients should have a good performance status and can have locally relapsed disease or second primary cancers, and there are no absolute lung function values that preclude reirradiation; (2) a full diagnostic workup should be performed in patients with suspected local recurrence and; (3) any reirradiation should be delivered using optimal image guidance and highly conformal techniques. In addition, consensus cumulative dose for the organs at risk in the thorax are described. CONCLUSIONS: These consensus statements provide practical guidance on appropriate patient selection for reirradiation, appropriate radiation therapy techniques, and cumulative dose constraints.
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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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ItemDoes institutional patient accrual volume impact overall survival in patients with inoperable non-small-cell lung cancer receiving radical (chemo)radiation? A secondary analysis of TROG 99.05(WILEY, 2020-08)INTRODUCTION: Increased hospital patient volume, reflecting greater experience, has been shown to be associated with improved survival for some cancers. However, there is no evidence to support the volume-outcome hypothesis for inoperable non-small-cell lung cancer (NSCLC) patients within the Australasian setting. We examined the relationship between overall survival (OS) and institutional patient accrual volume (IPAV) in a large prospective Australasian NSCLC database (TROG 99.05). METHODS: TROG 99.05 was an observational study which accrued patients from 1999 to 2007 to examine the relationship between primary lung cancer volume and survival. To be eligible for inclusion, patients had to have inoperable, biopsy-proven NSCLC planned for radiotherapy to a minimum dose of 50Gy in 20 fractions, with or without chemotherapy. Participating institutions were de-identified and grouped according to whether accrual was low, medium or high. OS was compared between groups and adjusted for prognostic factors using Cox regression. RESULTS: About 509 patients were accrued from 16 centres. Median potential follow-up time was 60 months. Median survival for all groups was 20 months (95% CI 18.3-21.8 months). There were no statistically significant differences in OS with increasing patient accrual across the three groups after adjustment for prognostic factors (P = 0.84, 2 df). The hazard ratios (HR) for group accrual volumes, relative to that for high-accrual volume, were as follows: low, 1.18; medium, 1.14. Test for trend: HR = 0.91 per group (95% CI 0.76-1.09, P = 0.31). CONCLUSION: In the setting of a clinical trial with rigorous quality assurance, we found no evidence for an association between institutional accrual and survival.
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ItemAdverse respiratory outcomes following conventional long-course radiotherapy for non-small-cell lung cancer in patients with pre-existing pulmonary fibrosis: A comparative retrospective study(WILEY, 2020-08)INTRODUCTION: There is some evidence to suggest that patients with underlying pulmonary fibrosis (PF) have increased risk of adverse respiratory and survival outcomes, when treated with conventional, long-course radiotherapy (RT) for non-small-cell lung cancer (NSCLC). We performed a retrospective analysis to determine the size of these risks. METHODS: Data from 21 patients with PF (cases) were retrospectively analysed for respiratory toxicity and mortality outcomes, and compared with 84 patients without PF (non-cases). Age and mean lung dose were included as covariates in regression analyses. The additional predictive value of other patient, disease and treatment characteristics on radiation pneumonitis (RP) risk and severity was explored. RESULTS: There was a numerical (though not statistically significant) increase in grade ≥ 2 RP among PF cases (OR 2.74, P = 0.074). Cases were significantly more likely to discontinue radical treatment early (OR 6.10, P = 0.015). There was a significant association between increased RP severity and underlying PF (P = 0.039), with RP strongly implicated in the death in 3 of 21 cases (14.3%) compared to 1 non-case (1.2%). Cases experienced increased grade ≥ 2 respiratory toxicity otherwise (OR 4.35, P = 0.020) and poorer median overall survival (0.6 versus 1.7 years, P < 0.001). Two cases, and no non-cases, died during the proposed RT period. None of the analysed patient, disease or treatment factors, was a significant additional predictor of RP risk/severity. CONCLUSION: Patients with PF are at increased risk of treatment discontinuation, respiratory morbidity and mortality, and poor survival following conventional RT for NSCLC. Caution should be exercised when offering high-dose RT to these patients.
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