肢体软组织肉瘤术后放疗缩小放疗野的临床观察

Clinical efficacy of postoperative radiotherapy using shrinking field for patients with extremity soft tissue sarcoma

目的探讨肢体软组织肉瘤术后缩小放疗野放疗的效果,重点观察局部控制率和不良反应发生情况。方法回顾性分析2017年10月至2021年3月清华大学第一附属医院收治的49例肢体软组织肉瘤患者,所有患者术后均接受调强放疗。采用定位CT和术后MRI图像融合的方法进行靶区勾画,定义瘤床(GTV_(tb))在纵轴方向外扩3 cm,横轴方向外扩1.5 cm形成临床靶区(CTV,解剖屏障可适当修回,且需包全肿瘤周围水肿区)。GTV_(tb)和CTV分别外扩0.5 cm形成计划靶区1(PTV1)和PTV2,放疗处方剂量:PTV1_(95%)为63~66 Gy,PTV2_(95%)为50~56 Gy,单次1.8~2.0 Gy。若术后镜下切缘阳性,瘤床区域推量至70 Gy。结果随访7.9~45.6个月,中位随访时间32.1个月。3年无局部失败生存率、总生存率和无远处转移生存率分别为91.7%、77.6%、71.5%。单因素分析结果显示,术后镜下切缘阳性的患者更容易出现局部复发,P<0.05。2级及以上伤口并发症、关节僵硬、骨折、水肿、皮肤纤维化的发生率分别为2%、4.1%、2%、8.2%、26.5%。结论术后放疗缩小放射野治疗肢体软组织肉瘤得到了较好的局部控制率,且晚期不良反应发生率较低。

Objective To investigate the effectiveness of postoperative radiotherapy using shrinking field for patients with extremity soft tissue sarcoma(STS),mainly focusing on the local control rate and adverse events.Methods Clinical data of 49 extremity STS patients who received postoperative intensity-modulated radiotherapy in the First Hospital of Tsinghua University from October 2017 to March 2021 were retrospectively analyzed.Target volumes were contoured on CT and MRI fusion images.The tumor bed was defined as GTV_(tb),with 3 cm expansion in the longitudinal direction and 1.5 cm expansion in the radial direction to construct CTV(the target volume should be properly repaired according to the anatomical barrier,and the edema area around the tumor should be included).GTV_(tb)and CTV were expanded in all directions by 0.5 cm to construct PTV1 and PTV2 respectively,at a dose of 95%PTV163-66 Gy,95%PTV250-56 Gy,1.8-2.0 Gy/f.The dose of surgical volume should be given at 70 Gy for patients who had a microscopic positive margin.Results The median follow-up time was 32.1 months(7.9-45.6 months).The 3-year local failure-free survival(LFFS),overall survival(OS)and distant metastasis-free survival(DMFS)were 91.7%,77.6%and 71.5%,respectively.Univariate analysis showed that patients with a microscopic positive margin were more likely to develop local recurrence(P<0.05).The incidence of grade 2 or above wound complications,joint stiffness,fracture,edema and skin fibrosis were 2%,4.1%,2%,8.2%and 26.5%,respectively.Conclusion Postoperative radiotherapy with shrinking field provides excellent local control rate and low incidence of late adverse events in patients with extremity STS.