J Appl Clin Med Phys. 2026 Mar;27(3):e70537. doi: 10.1002/acm2.70537.
ABSTRACT
BACKGROUD: The expanding clinical use of helical tomotherapy (HT) has raised concerns regarding its potential to increase low-dose lung exposure and the risk of radiation pneumonitis (RP) in thoracic radiotherapy. While a few retrospective studies have compared dosimetric parameters and RP rates between HT and fixed-field intensity-modulated radiation therapy (IMRT), their findings remain inconsistent, necessitating a prospective randomized controlled trial for clarification.
PURPOSE: To prospectively compare dosimetric parameters and the incidence of RP between HT and IMRT in patients with lung or esophageal cancer.
METHODS: Patients eligible for thoracic radiotherapy were enrolled. Both HT and IMRT plans were designed and optimized for each patient, with a prescription equivalent dose in 2 Gy /fraction (EQD2) ≥50 Gy to the gross tumor volume (GTV). Plans were evaluated based on target dose coverage, dose-volume histograms, and other dosimetric indices. RP was diagnosed and graded according to the Common Terminology Criteria for Adverse Events (version 5.0). Risk factors for RP were identified using univariate analysis.
RESULTS: Between February and September 2022, 110 consecutive patients with lung or esophageal cancer were enrolled and randomly assigned in a 1:1 ratio to either the HT group (n = 54) or the IMRT group (n = 56). Compared with IMRT, HT had a significant reduction in lung V20 (p = 0.002) and mean lung dose (p = 0.013). Furthermore, the HT group exhibited a superior conformity index for the planning gross tumor volume of the primary lesion (PGTVp) (p = 0.004) and a lower homogeneity index for all planning target volumes (PTVs) (p < 0.001). At a median follow-up of 14.0 months, the rate of grade≥2 RP for the entire cohort was 14.5%, with no significant differences between the HT and IMRT groups (p = 0.61).
CONCLUSIONS: Compared with fixed-field IMRT, HT provided superior dose distribution to the PTVs while maintaining a comparable incidence of RP in patients undergoing thoracic radiotherapy.
PMID:41850745 | DOI:10.1002/acm2.70537
