Published online Jan 28, 2017. doi: 10.4329/wjr.v9.i1.17
Peer-review started: August 18, 2016
First decision: October 21, 2016
Revised: October 29, 2016
Accepted: November 21, 2016
Article in press: November 23, 2016
Published online: January 28, 2017
To noninvasively investigate tumor cellularity measured using diffusion-weighted magnetic resonance imaging (DW-MRI) and glucose metabolism measured by 18F-labeled fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) during radiation therapy (RT) for human papillomavirus negative (HPV-) head and neck squamous cell carcinoma (HNSCC).
In this prospective study, 6 HPV- HNSCC patients underwent a total of 34 multimodality imaging examinations (DW-MRI at 1.5 T Philips MRI scanner [(n = 24) pre-, during- (2-3 wk), and post-treatment (Tx), and 18F-FDG PET/CT pre- and post-Tx (n = 10)]. All patients received RT. Monoexponential modeling of the DW-MRI data yielded the imaging metric apparent diffusion coefficient (ADC) and the mean of standardized uptake value (SUV) was measured from 18F-FDG PET uptake. All patients had a clinical follow-up as the standard of care and survival status was documented at 1 year.
There was a strong negative correlation between the mean of pretreatment ADC (ρ = -0.67, P = 0.01) and the pretreatment 18F-FDG PET SUV. The percentage (%) change in delta (∆) ADC for primary tumors and neck nodal metastases between pre- and Wk2-3 Tx were as follows: 75.4% and 61.6%, respectively, for the patient with no evidence of disease, 27.5% and 32.7%, respectively, for those patients who were alive with disease, and 26.9% and 7.31%, respectively, for those who were dead with disease.
These results are preliminary in nature and are indicative, and not definitive, trends rendered by the imaging metrics due to the small sample size of HPV- HNSCC patients in a Meixoeiro Hospital of Vigo Experience.
Core tip: In the modern era of adaptive radiotherapy, it is crucial to understand how different imaging techniques interact and complement each other for application in cancer care. The quantitative imaging metrics, apparent diffusion coefficient and standardized uptake value, play a significant role in understanding the efficacy of the radiotherapy treatment. Tumor cellularity and glucose metabolism were investigated before, during, and after radiotherapy in human papillomavirus negative head and neck squamous cell carcinoma patients using the diffusion-weighted magnetic resonance imaging and 18F-labeled fluorodeoxyglucose positron emission tomography/computed tomography imaging techniques.