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. 2026 Mar 25;15(4):332. doi: 10.21037/tcr-2026-1-0320

Figure 1.

Figure 1

Comparison of conventional and de-escalated target delineation after induction chemotherapy. Conventional IG-2018 contours (A-pre/B-pre): nodes prescribed 66 Gy (blue), drainage levels prescribed 60 Gy (red). A-post/B-post show the study contours based on post-IC CT short-axis rules. (A) Within the left cervical level II region, a node with a post-IC short-axis diameter of 8–10 mm was delineated as GTVnd and prescribed 64 Gy (purple). The corresponding drainage level was included in CTV2 (orange, 50.4 Gy). (B) Within the left cervical level III region, a node with a post-IC CT short-axis <5 mm was incorporated directly into CTV2 (orange, 50.4 Gy) without GTVnd. CTV1 comprised regions surrounding the primary tumor and high-risk nodal drainage areas, and CTV2 included low-risk nodal drainage areas. CT, computed tomography; CTV, clinical target volume; GTVnd, nodal gross tumor volume; IC, induction chemotherapy.