Repeatability and reproducibility of magnetic resonance imaging-based radiomic features in rectal cancer.

Purpose: Radiomics of magnetic resonance images (MRIs) in rectal cancer can non-invasively characterize tumor heterogeneity with potential to discover new imaging biomarkers. However, for radiomics to be reliable, the imaging features measured must be stable and reproducible. The aim of this study is to quantify the repeatability and reproducibility of MRI-based radiomic features in rectal cancer. Approach: An MRI radiomics phantom was used to measure the longitudinal repeatability of radiomic features and the impact of post-processing changes related to image resolution and noise. Repeatability measurements in rectal cancers were also quantified in a cohort of 10 patients with test-retest imaging among two observers. Results: We found that many radiomic features, particularly from texture classes, were highly sensitive to changes in image resolution and noise. About 49% of features had coefficient of variations ≤ 10 % in longitudinal phantom measurements. About 75% of radiomic features in in vivo test-retest measurements had an intraclass correlation coefficient of ≥ 0.8 . We saw excellent interobserver agreement with mean Dice similarity coefficient of 0.95 ± 0.04 for test and retest scans. Conclusions: The results of this study show that even when using a consistent imaging protocol many radiomic features were unstable. Therefore, caution must be taken when selecting features for potential imaging biomarkers.

Early experience with MR-guided adaptive radiotherapy using a 1.5 T MR-Linac: First 6 months of operation using adapt to shape workflow.

INTRODUCTION: The magnetic resonance linear accelerator (MRL) offers improved soft tissue visualization to guide daily adaptive radiotherapy treatment. This manuscript aims to report initial experience using a 1.5 T MRL in the first 6 months of operation, including training, workflows, timings and dosimetric accuracy. METHODS: All staff received training in MRI safety and MRL workflows. Initial sites chosen for treatment were stereotactic and hypofractionated prostate, thoraco-abdomino-pelvic metastasis, prostate bed and bladder. The Adapt To Shape (ATS) workflow was chosen to be the focus of treatment as it is the most robust solution for daily adaptive radiotherapy. A workflow was created addressing patient suitability, simulation, planning, treatment and peer review. Treatment times were recorded breaking down into the various stages of treatment. RESULTS: A total of 37 patients were treated and 317 fractions delivered (of which 313 were delivered using an ATS workflow) in our initial 6 months. Average treatment times over the entire period were 50 and 38 min for stereotactic and non-stereotactic treatments respectively. Average treatment times reduced each month. The average difference between reference planned and ionization chamber measured dose was 0.0 ± 1.4%. CONCLUSION: The MRL was successfully established in an Australian setting. A focus on training and creating a detailed workflow from patient selection, review and treatment are paramount to establishing new treatment programmes.

A review on the impact of lung cancer multidisciplinary care on patient outcomes.

International guidelines recommend a multidisciplinary approach to the management of lung cancer due to the complexity of both patients and their disease and the multiple treatment options available. This care can be provided through patient discussion at multidisciplinary meetings where relevant medical and allied health staff formulate a consensus management plan taking all factors into consideration. This model can be extended further to include multidisciplinary clinics where the patient is present for assessment and discussion. However, conducting regular multidisciplinary meetings or clinics has significant time, resource and financial costs and therefore, it is important to assess the impact of multidisciplinary care. We aimed to review published evidence, from 2000 to 2019, to evaluate the impact of multidisciplinary care on lung cancer outcomes. There were 29 studies found, 11 evaluating multidisciplinary clinics, 14 studying multidisciplinary meetings and four where the model of care was not defined. There was only one randomised trial and three prospective studies, the remainder being retrospective studies. Despite limitations in trial design and confounding factors, overall, multidisciplinary care in lung cancer was associated with improvements in patient outcomes, in particular improved survival for all stages of lung cancer. Lung cancer patients managed in a multidisciplinary setting were more likely to receive active treatment and had improved utilisation of all treatment modalities: surgery, radiotherapy and chemotherapy. In addition, the treatment recommendations were more likely to be consistent with lung cancer management guidelines. These improved outcomes support the recommendations for a multidisciplinary approach to lung cancer care.