Promises and challenges for the implementation of computational medical imaging (radiomics) in oncology.

Medical image processing and analysis (also known as Radiomics) is a rapidly growing discipline that maps digital medical images into quantitative data, with the end goal of generating imaging biomarkers as decision support tools for clinical practice. The use of imaging data from routine clinical work-up has tremendous potential in improving cancer care by heightening understanding of tumor biology and aiding in the implementation of precision medicine. As a noninvasive method of assessing the tumor and its microenvironment in their entirety, radiomics allows the evaluation and monitoring of tumor characteristics such as temporal and spatial heterogeneity. One can observe a rapid increase in the number of computational medical imaging publications-milestones that have highlighted the utility of imaging biomarkers in oncology. Nevertheless, the use of radiomics as clinical biomarkers still necessitates amelioration and standardization in order to achieve routine clinical adoption. This Review addresses the critical issues to ensure the proper development of radiomics as a biomarker and facilitate its implementation in clinical practice.

Use of an intravaginal spacer in young girls treated with brachytherapy for bladder neck rhabdomyosarcoma: Dosimetric impact for organs at risk sparing and acute tolerance.

PURPOSE: Interstitial brachytherapy is indicated as part of a conservative strategy for children with bladder and/or prostate rhabdomyosarcoma (RMS), providing high local control probability with acceptable functional results. Vaginal and/or rectal complications were however reported, due to the close proximity to the implanted volume. We investigated the dosimetric impact of a vaginal spacer in terms of rectal and vaginal doses. METHODS AND PATIENTS: Medical records of 12 consecutive female patients with bladder neck RMS, median age 32 months (range: 1.3-6 years), were reviewed. Five patients were treated prior to 2017 without a vaginal spacer and seven patients treated after 2017 had their brachytherapy delivered with a vaginal spacer placed at time of implant. RESULTS: Minimal doses delivered to the most exposed 2cm3, 1cm3, and 0.5cm3 of the rectum were all statistically significantly lower among patients treated with a vaginal spacer, as compared to those treated without a spacer. Median rectal D2cm3 was 22GyEQD2 versus 38GyEQD2 (P=0.02), D1cm3 was 29GyEQD2 versus 51GyEQD2 (P=0.013), and D0.5cm3 was 32GyEQD2 versus 61GyEQD2 (P=0.017), with and without the vaginal spacer, respectively. The posterior vaginal wall D0.5cm3 dose was also significantly decreased, with median D0.5cm3 of 92GyEQD2 versus 54GyEQD2 (P<0.0001), with and without the spacer, respectively. Acute tolerance was excellent in all patients, with no need for replanning and no acute complication. CONCLUSIONS: The use of vaginal spacers in brachytherapy of female pediatric patients with bladder neck RMS resulted in significantly decreased doses to the rectum and the posterior vaginal wall. Though the clinical impact of such dose reduction remains undemonstrated, routine utilization of a vaginal spacer could be a method to decrease long-term morbidity in these patients.

[Computational medical imaging (radiomics) and potential for immuno-oncology]. / Imagerie médicale computationnelle (radiomique) et potentiel en immuno-oncologie.

The arrival of immunotherapy has profoundly changed the management of multiple cancers, obtaining unexpected tumour responses. However, until now, the majority of patients do not respond to these new treatments. The identification of biomarkers to determine precociously responding patients is a major challenge. Computational medical imaging (also known as radiomics) is a promising and rapidly growing discipline. This new approach consists in the analysis of high-dimensional data extracted from medical imaging, to further describe tumour phenotypes. This approach has the advantages of being non-invasive, capable of evaluating the tumour and its microenvironment in their entirety, thus characterising spatial heterogeneity, and being easily repeatable over time. The end goal of radiomics is to determine imaging biomarkers as decision support tools for clinical practice and to facilitate better understanding of cancer biology, allowing the assessment of the changes throughout the evolution of the disease and the therapeutic sequence. This review will develop the process of computational imaging analysis and present its potential in immuno-oncology.