Purpose The purpose of this study was to assess the feasibility, efficacy and toxicity of fiducial marker implantation and tracking in CyberKnife® stereotactic radiation therapy (SBRT) applied to extracranial locations. Materials and method This is a retrospective, single-centre, observational study to collect the data of all patients treated by stereotactic radiation therapy with fiducial marker tracking at extracranial locations, conducted between June 2014 and November 2017. Information regarding the implantation procedure, the types of toxicity related to marker implantation and the number of markers implanted/tracked during treatment were collected. Complication rates were evaluated using the CTCAE v4 [Common Terminology Criteria for Adverse Events] scale. The technical success rate was based on the ability to optimally track the tumor throughout all treatment fractions. Results Out of 2505 patients treated by stereotactic radiation therapy, 25% received treatment with fiducial marker tracking. The total number of implantation procedures was 616 and 1543 fiducial markers were implanted. The implantation-related complication rate was 3%, with 16 Grade 1 events and 4 Grade 2 events. The number of treated patients and the number of implanted markers has gradually increased since the technique was first implemented. The median treatment time was 27 min (range 10–76). 1295 fiducials were effectively tracked throughout all treatment fractions, corresponding to a technical success rate of 84%. The difference between the number of fiducials implanted and those tracked during treatment decreased significantly as the site’s experience increased. Conclusion Fiducial marker implantation and tracking is feasible, well-tolerated, and technically effective technique in SBRT for extracranial tumors.

The increasing interest in accurate pretreatment diagnosis of solid tumours by morphology, immunohistochemistry, genetics and molecular biology requires clinicians to obtain undamaged large core biopsies. Simultaneously, medical imaging and surgery give priority to minimal tissue injury, affordable technology and optimal patient compliance. A new large core soft tissue biopsy device has been developed to meet the above criteria. After intensive preclinical testing, 30 patients gave informed consent and 26 underwent the new diagnostic biopsy procedure. The sample was studied by morphology, immunohistochemistry and, where indicated, by molecular biology. Successful diagnosis was considered when in line with clinical follow-up and, as for all malignant lesions, when confirmed by open biopsy or surgery. No difficulties in the technique were encountered in 25 patients. In one patient the procedure was prematurely stopped because of anxiety. In all other 25 procedures a complete diagnosis was reached with regard to morphology, immunohistochemistry and molecular biology. A number of radiologists suggested some automation of the technique. This new large core soft tissue biopsy system performs well in the clinical context without injury to the breast parenchyma or artefacts in the harvested tissue specimen. The system meets almost all of the proposed technical and financial requirements. Automation is underway.

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