12/26/2023 0 Comments Cross contouring![]() To develop standardized contouring guidelines and to ensure adequacy of the CTV for ongoing and future clinical trials of radiotherapy for esophageal and GEJ cancers, we convened a panel of expert gastrointestinal radiation oncologists to generate a reference atlas for modern-day contouring. A remedy for this gap in clinical practice is important since it has been demonstrated that variation in target volume delineation may impact outcome of therapy and can be improved with atlases that serve as teaching aids in GI tract neoplasms. However, no consensus reference contouring guidelines or atlas is available to guide target delineation for patients on these trials. ![]() Although traditional guidelines for field design still govern contouring for IMRT in a broad sense, they are not likely to provide sufficient detail to ensure consistent delineation of target volumes between practitioners and patients.Ĭurrent prospective trials involving radiotherapy and esophageal cancer generally require three-dimensional conformal RT (3D-CRT), and may allow the use of IMRT. However, highly conformal radiation techniques require the radiation oncologist to define target volumes with greater specificity, utilizing CT-derived images and anatomy. These techniques allow for greater sparing of normal tissues, particularly the lungs and heart. Intensity-modulated radiation therapy (IMRT) and other highly conformal techniques, including volumetric arc therapy (VMAT) and proton therapy, represent an important advance in radiation therapy. In modern radiotherapy practice, treatment volumes are more commonly defined based on the ICRU definitions of clinical target volume (CTV) and planning target volume (PTV). To encompass subclinical disease extension and regional nodal spread, typical field borders were designated by 5cm expansions proximally and distally beyond apparent tumor along the length of the esophagus, and 2cm laterally, with these guidelines referring to distance to field or block edge. Traditionally, RT fields have been designed based on two-dimensional planning, using esophagrams to identify the primary lesion and utilizing simple geometric expansions and bony landmarks to shape radiation fields. ![]() When used as preoperative therapy, chemoradiation improves rates of margin-negative resection, pathologic complete response, and long-term survival. Definitive concurrent chemoradiotherapy can achieve long-term survival in a subset of patients. Radiotherapy (RT) has an important role in the treatment of esophageal and gastro-esophageal junction (GEJ) cancer, both in the definitive and preoperative settings. ![]()
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