Department of Radiation Oncology, University of North Carolina, 101 Manning Dr., Chapel Hill, NC, 27599-7512, USA.
Radiat Oncol. 2021 Mar 21;16(1):56. doi: 10.1186/s13014-021-01786-6.
Whole brain radiation (WBRT) may lead to acute xerostomia and dry eye from incidental parotid and lacrimal exposure, respectively. We performed a prospective observational study to assess the incidence/severity of this toxicity. We herein perform a secondary analysis relating parotid and lacrimal dosimetric parameters to normal tissue complication probability (NTCP) rates and associated models.
Patients received WBRT to 25-40 Gy in 10-20 fractions using 3D-conformal radiation therapy without prospective delineation of the parotids or lacrimals. Patients completed questionnaires at baseline and 1 month post-WBRT. Xerostomia was assessed using the University of Michigan xerostomia score (scored 0-100, toxicity defined as ≥ 20 pt increase) and xerostomia bother score (scored from 0 to 3, toxicity defined as ≥ 2 pt increase). Dry eye was assessed using the Subjective Evaluation of Symptom of Dryness (SESoD, scored from 0 to 4, toxicity defined as ≥ 2 pt increase). The clinical data were fitted by the Lyman-Kutcher-Burman (LKB) and Relative Seriality (RS) NTCP models.
Of 55 evaluable patients, 19 (35%) had ≥ 20 point increase in xerostomia score, 11 (20%) had ≥ 2 point increase in xerostomia bother score, and 13 (24%) had ≥ 2 point increase in SESoD score. For xerostomia, parotid V-V correlated best with toxicity, with AUC 0.68 for xerostomia score and 0.69-0.71 for bother score. The values for the D, m and n parameters of the LKB model were 22.3 Gy, 0.84 and 1.0 for xerostomia score and 28.4 Gy, 0.55 and 1.0 for bother score, respectively. The corresponding values for the D, γ and s parameters of the RS model were 23.5 Gy, 0.28 and 0.0001 for xerostomia score and 32.0 Gy, 0.45 and 0.0001 for bother score, respectively. For dry eye, lacrimal V-V were found to correlate best with toxicity, with AUC values from 0.67 to 0.68. The parameter values of the LKB model were 53.5 Gy, 0.74 and 1.0, whereas of the RS model were 54.0 Gy, 0.37 and 0.0001, respectively.
Xerostomia was most associated with parotid V-V, and dry eye with lacrimal V-V. NTCP models were successfully created for both toxicities and may help clinicians refine dosimetric goals and assess levels of risk in patients receiving palliative WBRT.
全脑放疗（WBRT）可能会导致腮腺和泪腺意外照射引起的急性口干和干眼症。我们进行了一项前瞻性观察研究，以评估这种毒性的发生率/严重程度。我们在此进行二次分析，将腮腺和泪腺剂量学参数与正常组织并发症概率（NTCP）率及其相关模型相关联。
患者接受 25-40Gy 的 WBRT，分 10-20 次进行，使用 3D 适形放疗，不前瞻性地划定腮腺或泪腺。患者在 WBRT 前后 1 个月完成问卷调查。口干使用密歇根大学口干量表（评分为 0-100，毒性定义为≥20 分增加）和口干困扰评分（评分为 0-3，毒性定义为≥2 分增加）进行评估。干眼症使用主观评估干燥症状（SESoD，评分为 0-4，毒性定义为≥2 分增加）进行评估。临床数据通过 Lyman-Kutcher-Burman（LKB）和相对连续性（RS）NTCP 模型进行拟合。
在 55 例可评估患者中，19 例（35%）口干评分增加≥20 分，11 例（20%）口干困扰评分增加≥2 分，13 例（24%）SESoD 评分增加≥2 分。对于口干，腮腺 V-V 与毒性相关性最好，口干评分的 AUC 为 0.68，口干困扰评分的 AUC 为 0.69-0.71。LKB 模型的 D、m 和 n 参数值分别为 22.3Gy、0.84 和 1.0 用于口干评分和 28.4Gy、0.55 和 1.0 用于困扰评分。RS 模型相应的 D、γ和 s 参数值分别为 23.5Gy、0.28 和 0.0001 用于口干评分和 32.0Gy、0.45 和 0.0001 用于困扰评分。对于干眼症，发现泪腺 V-V 与毒性相关性最好，AUC 值为 0.67-0.68。LKB 模型的参数值分别为 53.5Gy、0.74 和 1.0，而 RS 模型的参数值分别为 54.0Gy、0.37 和 0.0001。
口干与腮腺 V-V 相关性最强，干眼症与泪腺 V-V 相关性最强。成功为这两种毒性创建了 NTCP 模型，这可能有助于临床医生优化剂量学目标，并评估接受姑息性 WBRT 治疗的患者的风险水平。
