Department of Radiation Oncology, Calvary Mater Newcastle, Waratah, NSW, Australia; Faculty of Medicine and Health, Sydney Medical School, The University of Sydney, Sydney, NSW, Australia.
Department of Radiation Oncology, Cancer Therapy Centre, Liverpool Hospital, Liverpool, NSW, Australia; South Western Clinical School, School of Medicine, University of New South Wales, NSW, Australia.
Radiother Oncol. 2023 Sep;186:109745. doi: 10.1016/j.radonc.2023.109745. Epub 2023 Jun 15.
The aim of this study was to measure functional changes in parotid glands using mid-treatment FDG-PET/CT and correlate early imaging changes to subsequent xerostomia in mucosal head and neck squamous cell carcinoma patients undergoing radiotherapy.
56 patients from two prospective imaging biomarker studies underwent FDG-PET/CT at baseline and during radiotherapy (week 3). Both parotid glands were volumetrically delineated at each time point. PET parameter SUV were calculated for ipsilateral and contralateral parotid glands. Absolute and relative change (Δ) in SUV were correlated to moderate-severe xerostomia (CTCAE grade ≥ 2) at 6 months. Four predictive models were subsequently created using multivariate logistic regression using clinical and radiotherapy planning parameters. Model performance was calculated using ROC analysis and compared using Akaike information criterion (AIC) RESULTS: 29 patients (51.8%) developed grade ≥ 2 xerostomia. Compared to baseline, there was an increase in SUV at week 3 in ipsilateral (8.4%) and contralateral (5.5%) parotid glands. Increase in ipsilateral parotid Δ SUV (p = 0.04) and contralateral mean parotid dose (p = 0.04) were correlated to xerostomia. The reference 'clinical' model correlated to xerostomia (AUC 0.667, AIC 70.9). Addition of ipsilateral parotid Δ SUV to the clinical model resulted in the highest correlation to xerostomia (AUC 0.777, AIC 65.4).
Our study shows functional changes occurring in the parotid gland early during radiotherapy. We demonstrate that integration of baseline and mid-treatment FDG-PET/CT changes in the parotid gland with clinical factors has the potential to improve xerostomia risk prediction which could be utilised for personalised head and neck radiotherapy.
本研究旨在通过治疗中期 FDG-PET/CT 测量腮腺功能变化，并将早期影像学变化与接受放疗的头颈部黏膜鳞状细胞癌患者随后发生的口干症相关联。
从两项前瞻性影像生物标志物研究中招募了 56 名患者，他们在基线和放疗期间（第 3 周）接受了 FDG-PET/CT 检查。在每个时间点都对双侧腮腺进行了容积勾画。为同侧和对侧腮腺计算了 PET 参数 SUV。SUV 的绝对和相对变化（Δ）与 6 个月时的中度至重度口干症（CTCAE 分级≥2）相关联。随后使用多元逻辑回归和临床及放疗计划参数创建了四个预测模型。使用 ROC 分析计算模型性能，并使用 Akaike 信息准则（AIC）进行比较。
29 名患者（51.8%）发生了≥2 级口干症。与基线相比，同侧（8.4%）和对侧（5.5%）腮腺在第 3 周时 SUV 增加。同侧腮腺 Δ SUV 增加（p=0.04）和对侧腮腺平均剂量增加（p=0.04）与口干症相关联。参考“临床”模型与口干症相关联（AUC 0.667，AIC 70.9）。将同侧腮腺 Δ SUV 添加到临床模型中，与口干症的相关性最高（AUC 0.777，AIC 65.4）。
我们的研究表明，在放疗早期，腮腺功能发生了变化。我们证明，将基线和治疗中期 FDG-PET/CT 腮腺变化与临床因素相结合，有可能提高口干症风险预测的准确性，从而为个性化头颈部放疗提供依据。
