Affiliated Foshan Maternity & Child Healthcare Hospital, Southern Medical University, Foshan, China; Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, China; Department of Radiation Oncology, First Medical Center of Chinese PLA General Hospital, Beijing, China; Armed Police Corps Hospital of Henan Province, Zhengzhou, China.
Department of Radiation Oncology, Center of Respiratory Medicine, China-Japan Friendship Hospital, Beijing, China.
Radiother Oncol. 2021 Apr;157:247-254. doi: 10.1016/j.radonc.2021.02.004. Epub 2021 Feb 13.
To verify clinical significance of submandibular gland (SMG)-sparing during helical tomotherapy (HT) for nasopharyngeal carcinoma (NPC) from the perspective of imaging by using diffusion weighted imaging (DWI).
In this prospective study, 60 NPC patients scheduled for radical SMG-sparing HT were enrolled. All patients underwent DWI examinations prior to HT (pre-HT) and 1, 3, 6, 9, 12 months post HT. Mean apparent diffusion coefficient (ADC) values of bilateral parotid glands (PGs) and submandibular glands (SMGs) were measured. Differences of ADC and changes of ADC pre and pro HT (ΔADC) among SMG-spared, SMG-unspared and PGs were compared and the associations betweenΔADC and variations of patient-rated xerostomia questionnaire summary scores (XQ-sum) were further tested.
ADC and ΔADC of SMG-spared were both much lower than of SMG-unspared and a strong dose-response relationship was detected between mean radiation dose and ΔADC of SMGs. Dynamic change trends of PGs, SMG-spared and SMG-unspared were similar, with initial increase at 1 m-post-HT followed by little change at 3 m-post-HT and then gradual decrease over time. But for SMG-unspared, there was no obvious change of ADC from 6 m-post-HT to 12 m-post-HT. The dynamic change trend of XQ-sum was nearly in line with that of ADC on the whole. And a positive correlation between mean ΔADC of bilateral SMGs and variation of XQ-sum in patients with bSMG-unspared were found (r = 0.693, P < 0.001). Multivariate stepwise regression analysis showed that whether spared SMG or not was the only independent predictor correlated to XQ-sum at each follow-up timepoint.
SMG-sparing technique could significantly improve subjective xerostomia post HT in NPC patients from the perspective of imaging.
从影像学角度，通过扩散加权成像（DWI）验证螺旋断层放疗（HT）治疗鼻咽癌（NPC）时保留颌下腺（SMG）的临床意义。
前瞻性研究纳入 60 例计划行根治性保留 SMG 的 NPC 患者。所有患者在 HT 前（pre-HT）和 HT 后 1、3、6、9、12 个月均行 DWI 检查。测量双侧腮腺（PG）和颌下腺（SMG）的平均表观扩散系数（ADC）值。比较颌下腺保留、未保留和腮腺之间 ADC 的差异和 HT 前后 ADC 的变化（ΔADC），进一步检测ΔADC 与患者口干症状自评量表总分（XQ-sum）变化的相关性。
SMG 保留组的 ADC 和ΔADC 均明显低于未保留组，且 SMG 的平均辐射剂量与ΔADC 之间存在较强的剂量-反应关系。PG、SMG 保留和未保留的动态变化趋势相似，在 HT 后 1 个月时最初增加，然后在 3 个月时几乎不变，随后随时间逐渐减少。但对于未保留颌下腺的患者，从 HT 后 6 个月到 12 个月，ADC 没有明显变化。XQ-sum 的动态变化趋势总体上与 ADC 相似。并且，发现在未保留双侧 SMG 的患者中，双侧 SMG 的平均ΔADC 与 XQ-sum 的变化呈正相关（r=0.693，P<0.001）。多因素逐步回归分析显示，是否保留 SMG 是与每个随访时间点 XQ-sum 相关的唯一独立预测因素。
从影像学角度来看，SMG 保留技术可显著改善 NPC 患者 HT 后口干的主观症状。
