van Rijn-Dekker Maria I, van der Schaaf Arjen, Nienhuis Sanne W, Arents-Huls Antoinette S, Ger Rachel B, Hamming-Vrieze Olga, Hoebers Frank J P, de Ridder Mischa, Vigorito Sabrina, Zwijnenburg Ellen M, Langendijk Johannes A, van Luijk Peter, Steenbakkers Roel J H M
Department of Radiation Oncology, University Medical Centre Groningen, University of Groningen, 9700 RB Groningen, The Netherlands.
Department of Radiation Oncology, Radiotherapiegroep, 6815 AD Arnhem, The Netherlands.
Cancers (Basel). 2024 Dec 23;16(24):4283. doi: 10.3390/cancers16244283.
BACKGROUND/OBJECTIVES: Studies have shown that dose to the parotid gland stem cell rich (SCR) regions should be reduced to lower the risk of xerostomia after radiotherapy (RT). This study aimed to assess whether stem cell sparing (SCS)-RT can be adopted in routine clinical practice.
Multiple planning studies were performed to compare SCS-RT with standard (ST)-RT using 30 head and neck cancer patients. Shifts in mean dose to the SCR regions (D) and other organs at risk and their estimated impact on normal tissue complication probability (NTCP) for side-effects were compared using Wilcoxon signed-rank test. A multicenter study was performed (eight institutions, three patients) to test the generalizability of SCS-RT using the Friedman test.
Using photons, D was reduced with median 4.1/3.5 Gy for ipsilateral/contralateral ( < 0.001). The largest reductions were when the SCR regions overlapped less with target volumes. Subsequently, NTCPs for xerostomia decreased ( < 0.001). Using protons, D was also reduced (2.2/1.9 Gy for ipsilateral/contralateral, < 0.002). Nevertheless, SCS-RT did not further decrease NTCPs for xerostomia ( > 0.17). Target coverage and prevention of other side-effects were not compromised. However, increased mean oral cavity dose was observed in some patients. Lastly, in the multicenter study D could be reduced by slightly adjusting the standard optimization. Contralateral D reductions differed between centers ( = 0.01), which was attributed to differences in ST-RT plans.
Stem cell sparing radiotherapy can be clinically introduced by making small adjustments to the optimization strategy and can reduce the risk of xerostomia.
背景/目的：研究表明，应降低腮腺富含干细胞（SCR）区域的照射剂量，以降低放疗（RT）后口干症的风险。本研究旨在评估干细胞保留（SCS）-RT是否可应用于常规临床实践。
对30例头颈癌患者进行了多项计划研究，比较SCS-RT与标准（ST）-RT。使用Wilcoxon符号秩检验比较SCR区域平均剂量（D）和其他危及器官的剂量变化及其对副作用的正常组织并发症概率（NTCP）的估计影响。进行了一项多中心研究（八个机构，三名患者），使用Friedman检验来测试SCS-RT的可推广性。
使用光子时，同侧/对侧D分别降低了4.1/3.5 Gy（<0.001）。最大降幅出现在SCR区域与靶体积重叠较少时。随后，口干症的NTCP降低（<0.001）。使用质子时，D也降低了（同侧/对侧为2.2/1.9 Gy，<0.002）。然而，SCS-RT并未进一步降低口干症的NTCP（>0.17）。靶区覆盖和其他副作用的预防未受影响。然而，在一些患者中观察到口腔平均剂量增加。最后，在多中心研究中，通过稍微调整标准优化可以降低D。中心之间对侧D的降低存在差异（=0.01），这归因于ST-RT计划的差异。
通过对优化策略进行小的调整，干细胞保留放疗可在临床上应用，并可降低口干症的风险。
