Proposal for the delineation of neoadjuvant target volumes in oesophageal cancer

Abstract

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Thorough design and pre-trial quality assurance (QA) decrease dosimetric impact of delineation and dose planning variability in the STRICTLUNG and STARLUNG trials for stereotactic body radiotherapy (SBRT) of central and ultra-central lung tumours

“…We brought the effect of the geometric contour variability a step further than suggested in guidelines and former studies by converting the geometrical variations into their dosimetrical impact [11,15,[23][24][25][26]. We observe, that in heterogeneous dose escalation with steep gradients, even minor deviations in OAR contours lead to large dosimetric variations and hereby risk of severe toxicity.…”

“…Former studies on delineation uncertainties report on geometric measures as e.g. Dice similarity coefficient (DSC) and mean surface distance [23][24][25]. In this study, we bring this a step further and report on the dosimetric consequences of OAR delineation variations in treatments with very steep dose gradients which may potentially lead to lethal toxicity.…”

The Key Clinical Questions of Neoadjuvant Chemoradiotherapy for Resectable Esophageal Cancer—A Review

“…GTVp includes the primary tumor also based on multi-modal image fusion including endoscopic ultrasonography (EUS), computerized tomography (CT) scan, magnetic resonance imaging (MRI), and fluorodeoxyglucose positron-emission tomography (FDG-PET), and endoscopic fiducial markers should be included. In the European Society for Radiation Oncology (ESTRO) proposal ( 17 ), “CTVp includes the GTVp with an expansion of 1.0 cm radially and 3.0 cm cranio-caudally along the esophageal wall. For tumours in the lower esophagus and gastro-esophageal junction (GEJ), the CTVp is restricted to 2.0 cm distal to the tumour”.…”

“…The use of EUS-guided fine-needle aspiration cytology (FNAC), which will increase the accuracy of regional lymph node to approximately 85% ( 19 ), is recommended in case of doubt and when it is associated with the delineation of the target volume. In the ESTRO proposal ( 17 ), the clinical target volume of the nodes (CTVn) includes the GTVn with an increase in 1.0 cm in all directions, and the involved lymph node stations, including the vena azygos, the aortic-pulmonal fenestra, and the fatty tissue of the arteria gastrica sinistra and of the subcarinal, para/pretracheal, paracardial, and supraclavicular region as long as they are up to 3.0 cm cranio-caudally from GTVp, should be additionally irradiated. However, we believe that the target area involved above is too large, and they may adversely affect treatment complication risks.…”

Value of PET imaging for radiation therapy

“…Additionally, results from a small prospective clinical trial suggest a significant benefit of additional PET imaging, with 6 out of 20 patients enrolled receiving subsequent modifications to their radiation treatment following FDG-PET/CT when compared to patients receiving conventional imaging [85]. A recently published delineation proposal of neoadjuvant target volumes in EC is also based on FDG-PET imaging, optimally acquired in treatment position [86]. Furthermore, preliminary retrospective data suggest that inclusion of PET into treatment planning potentially improves survival compared to conventional imaging [87].…”