Overlap-adapted Subvolume Prescription to Reduce Temporal Lobe Injury Risk in T4 Nasopharyngeal Carcinoma: A Prospective Cohort Study with a Contemporaneous Comparator.

Authors

Huadong Liao, Jing Wang, Yongzheng Lai, Peng Ding, Yong Su, Qing Dong, Liping Hu, Lan Liu, Xiying Gao, Honghui Xie, Yun Xiao, Lei Zeng, Tianzhu Lu, Xiaochang Gong, Jingao Li

Published in

Practical radiation oncology. Aug 21, 2026. Epub Aug 21, 2026.

Abstract

Radiation-induced temporal lobe injury (RTLI) remains a major late toxicity in T4 nasopharyngeal carcinoma (NPC) because primary target volumes frequently overlap the temporal lobe planning risk volume (PRV), limiting near-maximum dose constraints. This study evaluated the long-term safety and efficacy of an overlap-adapted subvolume prescription strategy.
This non-randomized, single-institution, prospective observational cohort study with a contemporaneous comparator (ClinicalTrials.gov identifier: XXXX) enrolled patients with T4N0-3M0 NPC treated between 2018 and 2022 who had planning target volume (PTV)-temporal lobe PRV overlap ≥ 0.1 cm³. The modified delineation and planning (MD) approach subdivided the primary tumor PTV (PTVnx) into a non-overlap subvolume (PTVsv1, prescribed 70 Gy) and an overlapping subvolume (PTVsv2, prescribed 66 Gy) using simultaneous integrated boost. The standard delineation and planning (SD) approach prescribed a uniform 70 Gy to the entire PTVnx.
Among 361 patients (MD, n = 104; SD, n = 257), the 5-year cumulative incidence of RTLI was significantly lower in the MD group (23.2% versus 36.2%; P = 0.019). Multivariable analysis revealed that MD was independently associated with reduced RTLI risk (hazard ratio = 0.56; 95% confidence interval: 0.34-0.94; P = 0.029). No significant differences were found in 5-year local relapse-free survival (92.3% versus 89.6%; P = 0.577) or overall survival (84.7% versus 84.4%; P = 0.896). No marginal recurrences were confined to PTVsv2. After lobe-level propensity-score matching (205 lobes per group), MD achieved significantly lower temporal-lobe Dmax and D1cc (both P < 0.001) without differences in V40-V60 and a borderline reduction in V65 (P = 0.053).
An overlap-adapted subvolume prescription strategy (66 Gy to PTVsv2) significantly reduced the incidence of radiographic RTLI while preserving long-term tumor control in anatomically constrained T4 NPC. The reduction in symptomatic RTLI was numerical but did not reach statistical significance and warrants further validation.

PMID:
42628876
Bibliographic data and abstract were imported from PubMed on 22 Aug 2026.

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