Modified reduced-volume intensity-modulated radiation therapy in non-metastatic nasopharyngeal carcinoma: A prospective observation series

Highlights: • "Modified reduced-volume IMRT" was re-defined based on our previous reported technique "reduced-volume IMRT". • "Modified reduced-volume IMRT" omitted CTV1 and narrowed the margin of CTV2. • This de-intensification technique was feasible and did not compromise therapeutic efficacy. • This renew technique simplified the procedures of target contouring and optimization of RT plan. Although the efficacy of "reduced-volume intensity-modulated radiation therapy (IMRT)" in nasopharyngeal carcinoma (NPC) has been confirmed, two issues regarding the necessity of clinical target volume 1(CTV1) delineation and the optimal margin of CTV2 remained undetermined. The current series, utilized de-intensification technique that omitted the contouring of CTV1 and narrowed the margin of CTV2 from 10 mm to 8 mm, namely "modified reduced-volume IMRT" was initiated to evaluate the efficacy and feasibility of this renew technique in a prospective series.