Delineation of Target Volumes of Neoadjuvant Radiation in Esophageal Squamous Cell Cancer in China: A Consensus Proposal

Background: To reach a consensus proposal on the delineation of target volumes of neoadjuvant radiation (nRT) in esophageal squamous cell cancer (ESCC) in China. Methods: : Nine ESCC patients (cases 1-9) who underwent nRT were retrospectively allocated from the Sun Yat-sen University Cancer Center and Shandong Cancer Hospital from February 2020 to June 2021. A working party composed of eight cancer radiotherapy centers delineated the patients’ nRT target volumes for two rounds: the first round of delineation included cases 1–6, and the second round included cases 7–9. After each round of delineation, the working party held an online meeting. Differences in mean undirected Hausdorff distances (Hmean), dice similarity coefficient (DSC), and total volumes between two rounds were investigated with a Mann–Whitney U test. Results: : Delineations in the second round were more consistent between centers (the clinical target volume of the total volume (CTVtotal): mean DSC=0.76–0.81; mean Hmean=2.11–3.14 cm) than in the first round (CTVtotal: mean DSC=0.63–0.64; mean Hmean=5.66–7.34 cm；DSC and Hmean: p <0.050 between rounds). Finally, a proposal and an atlas were obtained for target volumes delineation in patients with ESCC who will be treated with nRT. Conclusions: : involved field irradiation is widely recommended for ESCC treatment in China. Elective nodal irradiation should be administered to the supraclavicular and abdominal lymph nodes, and the range of prophylactic irradiation should not be too large. The formation of the proposal will greatly facilitate the promotion of nRT for ESCC and accurate delineation of target volumes.