ESTRO 2024 - Abstract Book

S5091

Physics - Radiomics, functional and biological imaging and outcome prediction

ESTRO 2024

segmentations. Local relapses (LR) were evaluated based on dimensional and functional criteria, such as tissue dynamic contrast enhancement, thus patients were accordingly classified as responders and non-responders. Local relapse free survival rates were estimated with the Kaplan-Meier product limit method (KM) and log-rank test was implemented to evaluate the association between any first order baseline or 6-months follow-up ADC feature and local relapse survival rates. Multivariable analysis was not deemed reasonable due to the small number of local relapse events. For the purpose of this analysis, quantitative variables were stratified based on their median value. Survival rates were reported on KM curves with the associated 95% binomial confidence intervals (95% CI), and the significance level was set to 5%.

Figure 1. Radiological images and adenoid cystic carcinoma contoured on high b-value (1000 [s/mm2])(a) and apparent diffusion coefficient maps (b), aided by T2-w TSE (c) and post-contrast T1-w vibe (d) sequences.

Results:

Consistent pre-treatment and 6-months follow-up radiological data were available for 41 and 29 patients, respectively. The median age was 57.5 years-old (range: 24-88 years-old), with 25 (61%) women and 16 (39%) men. In 34 (83%) patients, ACC primarily originated from minor salivary glands while in 7 (17%) ACC affected the major salivary glands. The most of patients 19 (46%) and 16 (39%) received a total dose of 65.6 Gy[RBE] and 68.8 Gy[RBE], respectively; while 5 (12%) and 1 (2%) patients were treated with a total dose of 60 Gy[RBE] and 61.6 Gy[RBE],