Determining optimal GTV-to-PGTV margins for CT-guided dose-escalated radiotherapy with daily image guidance in locally advanced rectal cancer.

ABSTRACT:

Background

Neoadjuvant chemoradiotherapy for locally advanced rectal cancer yields pathological complete response rates of only 10%-20%. Dose-escalation strategies may improve outcomes, but optimal GTV-to-PGTV margins for CT-guided radiotherapy with daily IGRT remain undefined.

Methods

Twelve LARC patients undergoing CT-guided daily IGRT with a simultaneous integrated boost were included. Daily diagnostic-quality fan-beam CT (FBCT) scans were acquired for IGRT. GTV and CTV were delineated on planning CT and all FBCTs. Target coverage margins were assessed by isotropically expanding the planning GTV until more than 95% of the voxels of the sequential GTVs were covered. A margin with a coverage probability threshold of 90% was defined as adequate. An independent validation coh

SUBMITTER: Qi X 

PROVIDER: S-EPMC12715369 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature