18FDG positron emission tomography mining for metabolic imaging biomarkers of radiation-induced xerostomia in patients with oropharyngeal cancer. (July 2021)

• Record Type: Journal Article
• Authors: Elhalawani, Hesham; Cardenas, Carlos E.; Volpe, Stefania; Barua, Souptik; Stieb, Sonja; Rock, Calvin B.; Lin, Timothy; Yang, Pei; Wu, Haijun; Zaveri, Jhankruti; Elgohari, Baher; Abdallah, Lamiaa E.; Jethanandani, Amit; Mohamed, Abdallah S.R.; Court, Laurence E.; Hutcheson, Katherine A.; Brandon Gunn, G.; Rosenthal, David I.; Frank, Steven J.; Garden, Adam S.; Rao, Arvind; Fuller, Clifton D.
• Is Part Of: Clinical and translational radiation oncology. Volume 29(2021)
• Page Start: 93
• Page End: 101
• Publication Date: 2021-07
• Subjects: Xerostomia -- FDG-PET -- Radiotherapy -- Imaging biomarkers -- Predictive model -- Head and neck cancer; Cancer -- Radiotherapy -- Periodicals; Oncology -- Periodicals; Cancer -- Radiotherapy; Oncology; Radiation Oncology; Neoplasms -- radiotherapy; Translational Medical Research; Periodicals; Electronic journals; Periodicals; 616.9940642
• DOI: 10.1016/j.ctro.2021.05.011
• Languages: English
• ISSNs: 2405-6308

Abstract

Highlights: Head and neck cancers radiotherapy (RT) leads to inevitable injury to parotid glands. We sought to quantify delta-changes of 18 FDG-PET metrics in these parotid glands. Parotid PET delta-changes and clinical variables could predict xerostomia severity. Abstract: Purpose: Head and neck cancers radiotherapy (RT) is associated with inevitable injury to parotid glands and subsequent xerostomia. We investigated the utility of SUV derived from 18 FDG-PET to develop metabolic imaging biomarkers (MIBs) of RT-related parotid injury. Methods: Data for oropharyngeal cancer (OPC) patients treated with RT at our institution between 2005 and 2015 with available planning computed tomography (CT), dose grid, pre- & first post-RT 18 FDG-PET-CT scans, and physician-reported xerostomia assessment at 3–6 months post-RT (Xero 3–6 ms) per CTCAE, was retrieved, following an IRB approval. A CT-CT deformable image co-registration followed by voxel-by-voxel resampling of pre & post-RT 18 FDG activity and dose grid were performed. Ipsilateral (Ipsi) and contralateral (contra) parotid glands were sub-segmented based on the received dose in 5 Gy increments, i.e. 0–5 Gy, 5–10 Gy sub-volumes, etc. Median and dose-weighted SUV were extracted from whole parotid volumes and sub-volumes on pre- & post-RT PET scans, using in-house code that runs on MATLAB. Wilcoxon signed-rank and Kruskal-Wallis tests were used to test differences pre- and post-RT. Results: 432 parotid glands, belonging to 108 OPC patients treated with RT, were sub-segmented & analyzed. Xero 3–6 ms was reported as: non-severe (78.7%) and severe (21.3%). SUV- median values were significantly reduced post-RT, irrespective of laterality (p = 0.02). A similar pattern was observed in parotid sub-volumes, especially ipsi parotid gland sub-volumes receiving doses 10–50 Gy (p < 0.05). Kruskal-Wallis test showed a significantly higher mean RT dose in the contra parotid in the patients with more severe Xero 3-6mo (p = 0.03). Multiple logistic regression showed a combined clinical-dosimetric-metabolic imaging model could predict the severity of Xero 3-6mo; AUC = 0.78 (95%CI: 0.66–0.85; p < 0.0001). Conclusion: We sought to quantify pre- and post-RT 18 FDG-PET metrics of parotid glands in patients with OPC. Temporal dynamics of PET-derived metrics can potentially serve as MIBs of RT-related xerostomia in concert with clinical and dosimetric variables.