Head and Neck Cancer

PV QA 2 - Poster Viewing Q&A 2

MO_24_2562 - Development of Temporal Dose-weighted Positron Emission Tomography Metabolic Imaging Biomarkers (PET MIBs) of Radiation-related Parotid Glands Injury in Oropharyngeal Cancer Patients

Monday, October 22
10:45 AM - 12:15 PM
Location: Innovation Hub, Exhibit Hall 3

Development of Temporal Dose-weighted Positron Emission Tomography Metabolic Imaging Biomarkers (PET MIBs) of Radiation-related Parotid Glands Injury in Oropharyngeal Cancer Patients
H. Elhalawani1, S. Volpe2, C. E. Cardenas2, S. Barua2, C. Rock3, T. Lin2, P. Yang4, H. Wu5, J. Zaveri2, B. Elgohari2, L. E. Abdallah6, A. Jethanandani7, A. S. Mohamed2, K. A. Hutcheson2, G. B. Gunn2, D. I. Rosenthal2, S. J. Frank2, A. S. Garden2, A. Rao8, and C. D. Fuller9; 1Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, 2The University of Texas MD Anderson Cancer Center, Houston, TX, 3University of Texas Health Science Center San Antonio School of Medicine, San Antonio, TX, 4Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, 5Xiangya Hospital of Central South University, Changsha, Hunan, China, 6Ain Shams University, Department of Clinical Oncology & Nuclear Medicine, Cairo, Egypt, 7The University of Tennessee Health Science Center College of Medicine, Memphis, TN, 8The University of Texas MD Anderson Cancer Center, Department of Bioinformatics and Computational Biology, Houston, TX, 9University of Texas Graduate School of Biomedical Sciences, Houston, TX

Purpose/Objective(s): Head and neck cancers (HNC) radiotherapy (RT) is associated with inevitable injury to parotid glands with subsequent xerostomia. Novel approaches to assess & predict degree of xerostomia are needed. We investigated the utility of standardized uptake values (SUV) derived from routinely performed FDG-PET-CT for staging and response evaluation to develop metabolic imaging biomarkers (MIBs) of RT-related parotid injury.

Materials/Methods: Oropharyngeal cancer (OPC) patients treated with RT at our institution from 2005-2015 with available pre- & post-RT PET-CT scans, planning CT and dose grid, and Xerostomia assessment at 6-months post-RT (Xero-6ms) were retrieved, following an IRB approval. After CT-CT deformable image co-registration using commercial software (Velocity AI), voxel-by-voxel resampling of pre & post-RT FDG activity and dose grid onto the treatment planning CT was done for analysis. Ipsilateral (ipsi) and contralateral (contra) parotid glands were sub segmented into smaller subvolumes based on the dose they received in 5 Gy increments, i.e. 0-5 Gy, 5-10 Gy subvolumes, etc. Volumetric as well as minimum, mean, median, maximum and dose-weighted SUV (calculated as: SUV * Planned parotid dose) were extracted from these whole parotids and sub volumes on pre- & post-RT PET scans, using in-house code that runs on a computer algorithm. Delta-changes of each metric were calculated as: [Post - Pre]/Pre. Investigation of variance of these metrics per dose level and subsequent correlation of their delta-changes to Xero-6ms were tested using Wilcoxon signed rank and Kruskal-Wallis tests.

Results: 480 parotid glands, belonging to 120 OPC patients treated with RT, were sub segmented & analyzed. Ipsi and contra parotid glands received a mean dose ‘Gy’ (Std) of 35.7 (12.2) & 19.8 (9.9). Xero-6ms was reported as: No (22.3%), mild/moderate (59.5%) or severe (18.2%). Using a Wilcoxon signed-rank test; volume was significantly reduced after RT irrespective of side (p<0.0001), while the SUV-mean, and SUV-median were significantly reduced on the ipsilateral side (p<0.005). Similar pattern was observed in parotid subvolumes which received doses ‘10-45 Gy’, especially ipsi parotid gland subvolumes receiving doses ’15-60 Gy’ (p<0.01). A Spearman rank correlation test showed that overall; delta SUV mean (rho = -0.14,p=0.03) and dose-weighted SUV mean (rho = -0.18,p=0.005) negatively correlates with mean dose, specifically for ipsi parotid dose-weighted SUV mean (rho = -0.23,p=0.011). Kruskal-Wallis test showed a lower reduction in volume of the contra parotid was associated with no Xero-6ms (p=0.029). The change in dose-weighted SUV in the ipsi gland was closely but not significantly associated with Xero-6ms grade (p=0.076).

Conclusion: Temporal dynamics of PET-derived metrics manifest dose-dependent changes that can be potential MIBs of RT-related parotid injury. Our results help generate hypothesis of the utility of integrating mid-RT PET-CT into adaptive RT trials for HNCs.

Author Disclosure: H. Elhalawani: Employee; MD Anderson Cancer Center. S. Volpe: None. C.E. Cardenas: None. C. Rock: None. T. Lin: None. H. Wu: None. J. Zaveri: None. B. Elgohari: None. A. Jethanandani: None. A.S. Mohamed: None. K.A. Hutcheson: None. G.B. Gunn: Associate Medical Director; MD Anderson Cancer Center - Proton Therapy. S.J. Frank: Research Grant; C4 Imaging, ELEKTA, U19. Founder and Director; C4 Imaging. Honoraria; ELEKTA, Varian Medican Systems, Inc. Advisory Board; Varian Medican Systems, Inc. Stock; C4 Imaging. Royalty; C4 Imaging. Patent/License Fees/Copyright; C4 Imaging. Chairman; American Brachytherapy Society. Director; C4 Imaging. Director-at-large; North America Skull Base Society. C.D. Fuller: Research Grant; National Institutes of Health, National Science Foundation, Elekta AB. Grant funding; Elekta AB. Honoraria; Nederlandse Organisatie voor Wetenschappelijk Onde. Consultant; Elekta AB, Nederlandse Organisatie voor Wetenschappelijk Onde. Travel Expenses; Elekta AB, Nederlandse Organisatie voor Wetenschappelijk Onde. Reviewer; Radiological Society of North America. Associate Editor; Radiographics. Data Management Task Force Committee Member; MR-LinAc Consortium. Member; National Cancer Institute. Task Group Member; American Association of Physicists in Medicine.

Send Email for Hesham Elhalawani


Assets

MO_24_2562 - Development of Temporal Dose-weighted Positron Emission Tomography Metabolic Imaging Biomarkers (PET MIBs) of Radiation-related Parotid Glands Injury in Oropharyngeal Cancer Patients



Attendees who have favorited this

Please enter your access key

The asset you are trying to access is locked. Please enter your access key to unlock.

Send Email for Development of Temporal Dose-weighted Positron Emission Tomography Metabolic Imaging Biomarkers (PET MIBs) of Radiation-related Parotid Glands Injury in Oropharyngeal Cancer Patients