Cao Xi, Liu Peilin, Gao Xian-Shu, Shang Shiyu, Liu Jiayu, Wang Zishen, Su Mengmeng, Ding Xuanfeng
Department of Radiation Oncology, Peking University First Hospital, Beijing, China.
Institute of Medical Technology, Peking University Health Science Center, Beijing, China.
Front Oncol. 2022 Jun 30;12:812031. doi: 10.3389/fonc.2022.812031. eCollection 2022.
To investigate the potential clinical benefit of utilizing intensity-modulated proton therapy (IMPT) to reduce acute hematologic toxicity for locally advanced non-small cell lung cancer (LA-NSCLC) patients and explore the feasibility of a model-based patient selection approach the normal tissue complication probability (NTCP).
Twenty patients with LA-NSCLC were retrospectively selected. Volumetric modulated arc photon therapy (VMAT) and IMPT plans were generated with a prescription dose of 60 Gy in 30 fractions. A wide range of cases with varied tumor size, location, stations of metastatic lymph nodes were selected to represent the general cancer group. Contouring and treatment planning followed RTOG-1308 protocol. Doses to thoracic vertebral bodies (TVB) and other organ at risks were compared. Risk of grade ≥ 3 acute hematologic toxicity (HT3+) were calculated based on the NTCP model, and patients with a reduction on NTCP of HT3+ from VMAT to IMPT (△NTCP_HT3+) ≥ 10% were considered to 'significantly benefit from proton therapy.'
Compared to VMAT, IMPT significantly reduced the dose to the TVB, the lung, the heart, the esophagus and the spinal cord. Tumor distance to TVB was significantly associated with △NTCP _HT3+ ≥ 10%. For the patients with tumor distance ≤ 0.7 cm to TVB, the absolute reduction of dose (mean, V30 and V40) to TVB was significantly lower than that in patients with tumor distance > 0.7 cm.
IMPT decreased the probability of HT3+ compared to VMAT by reducing the dose to the TVB in LA-NSCLC patients. Patients with tumor distance to TVB less than 0.7 cm are likely to benefit most from proton over photon therapy.
探讨利用调强质子治疗（IMPT）降低局部晚期非小细胞肺癌（LA - NSCLC）患者急性血液学毒性的潜在临床益处，并探索基于正常组织并发症概率（NTCP）模型的患者选择方法的可行性。
回顾性选取20例LA - NSCLC患者。采用容积调强弧形光子治疗（VMAT）和IMPT计划，处方剂量为60 Gy，分30次照射。选取肿瘤大小、位置、转移淋巴结部位各异的广泛病例以代表一般癌症群体。轮廓勾画和治疗计划遵循RTOG - 1308方案。比较胸椎椎体（TVB）和其他危及器官的剂量。基于NTCP模型计算≥3级急性血液学毒性（HT3 +）的风险，从VMAT到IMPT的HT3 +的NTCP降低（△NTCP_HT3 +）≥10%的患者被认为“从质子治疗中显著获益”。
与VMAT相比，IMPT显著降低了TVB、肺、心脏、食管和脊髓的剂量。肿瘤与TVB的距离与△NTCP _HT3 +≥10%显著相关。对于肿瘤与TVB距离≤0.7 cm的患者，TVB的剂量绝对降低值（平均值、V30和V40）显著低于肿瘤与TVB距离>0.7 cm的患者。
与VMAT相比，IMPT通过降低LA - NSCLC患者TVB的剂量降低了HT3 +的概率。肿瘤与TVB距离小于0.7 cm的患者可能从质子治疗而非光子治疗中获益最大。
