ESTRO 2022 - Abstract Book

S553

Abstract book

ESTRO 2022

Conclusion We have identified a potentially useful objective measure of response on WBMRI of vertebrae containing bone metastases in mHSPC which correlates with overall survival and subjective radiological response. Further studies are needed to validate our findings in a larger dataset.

References [1] A. Turpin et al. , Front. Oncol., 10 (55), 2020. [2] Turner PG, et al., Clin Cancer Res., 27(16), 2021.

OC-0625 Differences between HPV positive and negative oropharyngeal cancer detected by Non-Gaussian IVIM

N. Sijtsema 1,2 , I. Lauwers 1 , G. Verduijn 1 , D. Poot 2 , A. van der Lugt 2 , J. Hernandez-Tamames 2 , M. Hoogeman 1,3 , S. Petit 1

1 Erasmus MC Cancer Institute, Department of Radiotherapy, Rotterdam, The Netherlands; 2 Erasmus MC, Department of Radiology and Nuclear Medicine, Rotterdam, The Netherlands; 3 HollandPTC, Department of Medical Physics and Informatics, Delft, The Netherlands Purpose or Objective The apparent diffusion coefficient (ADC) of diffusion weighted imaging (DWI) has been associated with response to treatment for oropharyngeal squamous cell carcinoma (OPSCC). However, recently it has been suggested that ADC value is a surrogate of human papillomavirus (HPV) status, and not an independent prognostic factor. Non-Gaussian Intravoxel Incoherent Motion (NG-IVIM) imaging is a novel extension of conventional DWI that enables simultaneous assessment of microvascular perfusion and inter- and intra-cellular diffusion. This provides a more detailed picture of the tumor micro- environment than ADC only. Recently, we optimized NG-IVIM specifically for the head-and-neck region in volunteers. Here, for the first time, the optimized acquisition was applied in OPSCC patients. The aim of this study is to investigate the differences in NG-IVIM parameters between HPV positive (HPV+) and HPV negative (HPV-) OPSCC and compare NG-IVIM parameters to the ADC derived from conventional DWI.

Materials and Methods