Abstract：
OBJECTIVE: Concerns over chest wall toxicity has led to debates on treating tumors adjacent to the chest wall with single-fraction stereotactic ablative radiotherapy (SABR). We performed a secondary analysis of patients treated on the prospective iSABR trial to determine the incidence and grade of chest wall pain and modeled dose-response to guide radiation planning and estimate risk.
METHODS: This analysis included 99 tumors in 92 patients that were treated with 25 Gy in one fraction on the iSABR trial which individualized dose by tumor size and location. Toxicity events were prospectively collected and graded based on the CTCAE version 4. Dose-response modeling was performed using a logistic model with maximum likelihood method utilized for parameter fitting.
RESULTS: There were 22 grade 1 or higher chest wall pain events, including five grade 2 events and zero grade 3 or higher events. The volume receiving at least 11 Gy (V11Gy) and the minimum dose to the hottest 2 cc (D2cc) were most highly correlated with toxicity. When dichotomized by an estimated incidence of ≥ 20 % toxicity, the D2cc > 17 Gy (36.6 % vs. 3.7 %, p < 0.01) and V11Gy > 28 cc (40.0 % vs. 8.1 %, p < 0.01) constraints were predictive of chest wall pain, including among a subset of patients with tumors abutting or adjacent to the chest wall.
CONCLUSIONS: For small, peripheral tumors, single-fraction SABR is associated with modest rates of low-grade chest wall pain. Proximity to the chest wall may not contraindicate single fractionation when using highly conformal, image-guided techniques with sharp dose gradients.
METHODS: This analysis included 99 tumors in 92 patients that were treated with 25 Gy in one fraction on the iSABR trial which individualized dose by tumor size and location. Toxicity events were prospectively collected and graded based on the CTCAE version 4. Dose-response modeling was performed using a logistic model with maximum likelihood method utilized for parameter fitting.
RESULTS: There were 22 grade 1 or higher chest wall pain events, including five grade 2 events and zero grade 3 or higher events. The volume receiving at least 11 Gy (V11Gy) and the minimum dose to the hottest 2 cc (D2cc) were most highly correlated with toxicity. When dichotomized by an estimated incidence of ≥ 20 % toxicity, the D2cc > 17 Gy (36.6 % vs. 3.7 %, p < 0.01) and V11Gy > 28 cc (40.0 % vs. 8.1 %, p < 0.01) constraints were predictive of chest wall pain, including among a subset of patients with tumors abutting or adjacent to the chest wall.
CONCLUSIONS: For small, peripheral tumors, single-fraction SABR is associated with modest rates of low-grade chest wall pain. Proximity to the chest wall may not contraindicate single fractionation when using highly conformal, image-guided techniques with sharp dose gradients.
摘要：
目的：对胸壁毒性的担忧引发了关于单次立体定向消融放疗（SABR）治疗胸壁附近肿瘤的争论。我们对在前瞻性iSABR试验中接受治疗的患者进行了二次分析，以确定胸壁疼痛的发生率和等级，并对剂量反应进行建模，以指导放射计划和评估风险。
方法：该分析包括92例患者中的99例肿瘤，这些患者在iSABR试验中一次接受25Gy治疗，根据肿瘤大小和位置个体化剂量。前瞻性地收集毒性事件并基于CTCAE版本4进行分级。使用具有用于参数拟合的最大似然方法的逻辑模型进行剂量反应建模。
结果：有22例1级或以上的胸壁疼痛事件，包括五个2级事件和零个3级或更高的事件。接受至少11Gy(V11Gy)的体积和对最热的2cc(D2cc)的最小剂量与毒性高度相关。当通过估计≥20%的毒性发生率来划分时，D2cc>17Gy(36.6%与3.7%,p<0.01）和V11Gy>28cc（40.0%vs.8.1%,p<0.01)约束可预测胸壁疼痛，包括一部分邻近或邻近胸壁的肿瘤患者。
结论：对于小型，外周肿瘤,单部分SABR与轻度胸壁疼痛的适度发生率相关。使用高度适形时，接近胸壁可能不会禁止单一分割，具有尖锐剂量梯度的图像引导技术。
方法：该分析包括92例患者中的99例肿瘤，这些患者在iSABR试验中一次接受25Gy治疗，根据肿瘤大小和位置个体化剂量。前瞻性地收集毒性事件并基于CTCAE版本4进行分级。使用具有用于参数拟合的最大似然方法的逻辑模型进行剂量反应建模。
结果：有22例1级或以上的胸壁疼痛事件，包括五个2级事件和零个3级或更高的事件。接受至少11Gy(V11Gy)的体积和对最热的2cc(D2cc)的最小剂量与毒性高度相关。当通过估计≥20%的毒性发生率来划分时，D2cc>17Gy(36.6%与3.7%,p<0.01）和V11Gy>28cc（40.0%vs.8.1%,p<0.01)约束可预测胸壁疼痛，包括一部分邻近或邻近胸壁的肿瘤患者。
结论：对于小型，外周肿瘤,单部分SABR与轻度胸壁疼痛的适度发生率相关。使用高度适形时，接近胸壁可能不会禁止单一分割，具有尖锐剂量梯度的图像引导技术。
