Departments of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, United States; Department of Radiation Oncology, The Shanxi Cancer Hospital and Institute, Affiliated Hospital of Shanxi Medical University, Shanxi, China.
Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, United States.
Radiother Oncol. 2021 Jul;160:32-39. doi: 10.1016/j.radonc.2021.03.036. Epub 2021 Apr 8.
To determine rates of xerostomia after intensity-modulated radiotherapy (IMRT) or intensity-modulated proton therapy (IMPT) for oropharyngeal cancer (OPC) and identify dosimetric factors associated with xerostomia risk.
Patients with OPC who received IMRT (n = 429) or IMPT (n = 103) from January 2011 through June 2015 at a single institution were studied retrospectively. Every 3 months after treatment, each patient completed an eight-item self-reported xerostomia-specific questionnaire (XQ; summary XQ score, 0-100). An XQ score of 50 was selected as the demarcation value for moderate-severe (XQs ≥ 50) and no-mild (XQs < 50) xerostomia. The mean doses and percent volumes of organs at risk receiving various doses (V5-V70) were extracted from the initial treatment plans. The dosimetric variables and xerostomia risk were compared using an independent-sample t-test or chi-square test.
The median follow-up time was 36.2 months. The proportions of patients with moderate-severe xerostomia were similar in the two treatment groups up to 18 months after treatment. However, moderate-severe xerostomia was less common in the IMPT group than in the IMRT group at 18-24 months (6% vs. 20%; p = 0.025) and 24-36 months (6% vs. 20%; p = 0.01). During the late xerostomia period (24-36 months), high dose/volume exposures (V25-V70) in the oral cavity were associated with high proportions of patients with moderate-severe xerostomia (all p < 0.05), but dosimetric variables regarding the salivary glands were not associated with late xerostomia.
IMPT was associated with less late xerostomia than was IMRT in OPC patients. Oral cavity dosimetric variables were related to the occurrence of late xerostomia.
评估调强放疗（IMRT）或调强质子治疗（IMPT）治疗口咽癌（OPC）后的口干症发生率，并确定与口干症风险相关的剂量学因素。
回顾性分析 2011 年 1 月至 2015 年 6 月期间在单一机构接受 IMRT（n=429）或 IMPT（n=103）治疗的 OPC 患者。治疗后每 3 个月，每位患者完成一份八项口干症特异性问卷（XQ；总分 0-100）。选择 XQ 评分 50 作为中重度（XQs≥50）和无/轻度（XQs<50）口干症的分界线值。从初始治疗计划中提取危及器官的平均剂量和接受各种剂量（V5-V70）的体积百分比。采用独立样本 t 检验或卡方检验比较剂量学变量与口干症风险。
中位随访时间为 36.2 个月。治疗后 18 个月内，两组患者的中重度口干症比例相似。然而，在治疗后 18-24 个月（6%对 20%；p=0.025）和 24-36 个月（6%对 20%；p=0.01），IMPT 组中重度口干症的比例低于 IMRT 组。在晚期口干症期（24-36 个月），口腔高剂量/体积暴露（V25-V70）与中重度口干症患者比例较高相关（均 p<0.05），但唾液腺的剂量学变量与晚期口干症无关。
与 IMRT 相比，IMPT 治疗 OPC 患者的晚期口干症发生率较低。口腔剂量学变量与晚期口干症的发生有关。
