后程X线立体定向放射治疗局部晚期非小细胞肺癌的研究

Late-course hypofractionated stereotactic radiotherapy for locally advanced non small cell lung cancer

目的探讨后程大分割X线立体定向放射治疗在局部晚期非小细胞肺癌放射治疗中的作用。方法106例初治局部晚期(Ⅲa、Ⅲb期)非小细胞肺癌病例随机分为单纯常规放射治疗组(CRT)和后程立体定向放射治疗组(LCHSRT),完成治疗并且资料完整者共91例,CRT组43例,LCHSRT组48例。CRT组常规剂量分割大野对穿照射至43.5Gy后对原发肿瘤和转移淋巴结缩野加量至65.2Gy。LCHSRT组常规剂量分割大野对穿照射至44.4Gy后对原发肿瘤和转移淋巴结行大分割立体定向放射治疗,LCHSRT照射方式为圆形准直器非共面弧形照射,计划靶区体积边缘处方剂量4～7Gy/次,隔日1次,总剂量(22.8±5.5)Gy。结果CRT组和LCHSRT组放射性肺炎的发生率分别为11.6%和14.6%。放射治疗结束后3个月CT检查CRT与LCHSRT组局部肿瘤全消率分别为30.2%和63.5%(P<0.01);1年局部控制率分别为62.0%和86.5%(P>0.05);1年生存率分别为55.8%和79.2%(P<0.05)。两组急慢性放射性肺损伤差异均无显著性意义(χ2值分别为0.68和2.90,P值均>0.05)。结论圆形准直器非共面弧形照射后程大分割立体定向放射治疗提高了局部晚期非小细胞肺癌的局部肿瘤全消率和局部控制率,但其适形性和靶区内剂量均匀性不够理想,而且当照射剂量≥25Gy时放射性肺纤维化发生率明显增加。

Objective To evaluate the effect of late course hypofractionated stereotactic radiotherapy (LCHSRT) on locally advanced non small cell lung cancer. Methods From October 1997 to June 1999, 106 patients with locally advanced non small cell lung cancer were randomized into conventional radiotherapy group (CRT) and LCHSRT group. Ninety one patients with complete data were analyzed including 43 patients in CRT group and 48 patients in LCHSRT group. In CRT group, 18 patients were staged Ⅲa and 25 Ⅲb; whereas 19 patients were staged Ⅲa and 29 Ⅲb in LCHSRT group. The initial median dose of 43.5?Gy was given in CRT group to the primary tumor, ipsilateral hilum and mediastinum using AP PA fields with 1.8 2.0?Gy per fraction, then 21.7?Gy was boosted to the residual primary and metastatic regional lymph nodes to the median total dose of 65.2?Gy. In LCHSRT group, after the first 44.4?Gy to the primary tumor, ipsilateral hilar region and mediastinum by AP PA fields with a dose fraction of 1.8 2.0?Gy, noncoplanar arc hypofractionated stereotactic radiotherapy was delivered to the residual primary and metastatic lymph nodes to the total dose of (22.8±5.5)?Gy with 4 7?Gy per fraction treated every other day. Results The radiation pneumonitis rates were 11.6% and 14.6% in CRT group and LCHSRT group, respectively. The radiation pulmonary fibrosis rates diagnosed by CT scan 6 months after radiotherapy were 48.8% and 66.7% in CRT group and LCHSRT group, respectively. The complete regression (CR) rates evaluated by CT scan 3 months after treatment in CRT and LCHSRT group were 30.2% and 63.5%, respectively ( P<0.01). The 1 year local tumor control rates and the 1 year survival rates in CRT and LCHSRT group were 62%, 86.5%(P=0.054) and 55.8%, 79.2%(P<0.05), respectively. However, there was no statistical difference in 2 year survival between the two groups.Conclusions Late course hypofractionated stereotactic radiotherapy is a way to escalate the radiation dose to locally advanced non small cell lung cancer.