三维适形放疗与改良半胸照射放疗治疗弥漫性恶性胸膜间皮瘤的比较研究

Results of flexible 3D-conformal radiotherapy for patients with diffuse malignant pleural mesothelioma and comparative study of this technique with conventional radiotherapy

目的:弥漫性恶性胸膜间皮瘤治疗以手术和化疗为主,放疗常规采用半胸照射的技术,因肺损伤较大,使得放疗在弥漫性恶性胸膜间皮瘤治疗中的价值不明确。我们采用X射线三维适形放疗(3DCRT)加电子线野灵活布野的模式治疗8例弥漫性恶性胸膜间皮瘤,观察其近期疗效和放射损伤,并模拟改良的常规半胸照射放疗的方法,比较两种技术的肺损伤大小。方法:自2004年1月～2007年11月,我院收治的8例弥漫性恶性胸膜间皮瘤,其中5例为多程化疗失败者,3例为单纯放疗。化疗方案为GP、NP、TP和培美曲塞+卡铂,放疗采用X射线三维适形放疗和电子线野灵活布野的治疗模式,按常规分割的方式给予总量32.2～64.0Gy照射。同时模拟常规半胸照射放疗的技术,采用TPS系统模拟并计算肺的V20、V30和平均肺受量(MLD),与三维适形放疗和电子线野灵活布野的治疗模式相比较。结果:8例患者放疗后,1例患者达CR,其余患者均达PR。随访至2008年2月,2例患者死亡,其余6例均存活,平均生存时间为15.4个月。采用化疗+放疗者平均生存时间为18.8个月,单纯放疗组为9.7个月。采用三维适形放疗加电子线野灵活布野的治疗模式8例患者的平均V20为20.5%,V30为15.6%,患侧肺MLD为18.8Gy,健侧肺MLD2.2Gy。模拟常规半胸照射放疗技术8例患者的平均V20为36.8%,V30为27.9%,患侧肺MLD为31.1Gy,健侧肺MLD1.2Gy。两种技术的肺V20、V30和患侧肺MLD均存在差异,显示三维适形放疗加电子线野灵活布野的治疗模式可能有降低正常肺照射剂量的趋势;健侧肺MLD两者无明显差异。采用三维适形放疗加电子线野灵活布野治疗模式的8例患者均出现1～2度放射性肺炎。根据治疗前和治疗后生活质量评估显示治疗后的生活质量由治疗前的平均2.83上升为3.76,生活质量有所改善。结论:弥漫性恶性胸膜间皮瘤对放疗有一定的敏感性,采用三维适形放疗加电子线野灵活布野治疗模式是可行的,较改良的常规半胸照射放疗方式为佳,与相关文献相比较生存期无下降,但肺损伤明显减少,患者的生活质量有所改善。

Objective：Patients with diffuse malignant pleural mesothelionm （MPM） are mainly treated with surgery. Hemithoracic conventional radiotherapy （CRT） was mostly used for postoperative propose, and its severe radiation pneumonitis leads to the uncertainties of radiation in MPM treatment. New technique of flexible 3D-conformal radiotherapy （3DCRT） with combination of photon and electron is used in our study MPM and the comparative study of flexible 3DCRT and CRT was pursued to explore the possibility of radiation pneumonitis. Methods：From Jan. 2004 to Oct. 2007, 8 patients with MPM were treated with flexible 3DCRT. Five patients had received cycles of chemotherapy and 3 were treated with 3DCRT alone. New technique of flexible 3DCRT with combination of photon and electron was used in our study,and DT 32.2-64. 0Gy with conventional split were delivered. CRT technique was mimicked to compare with 3DCRT technique to explore the possibility of lung damage in two methods. Results：One patient reached CR and other 7 patients got PR after radiation. Two patients died during the follow-up. The median survival time （MST） was 15.4months and it was 18. 8months for sequential chemotherapy and radiotherapy group and 9.7months for radiotherapy alone. The V20, V30, ipsilateral and contralateral median lung dosage（MLD） was 20. 5% , 15.6% , 18.8Gy and 2. 2Gy respectively when the flexible 3DCRT technique was used, whereas it was 36. 8% , 27. 9%, 31. 1Gy and 1.2Gy respectively when the CRT technique was used. Values of the lung V20, V30 and ipsilateral MLD for the flexible 3DCRT technique were much less than those for the CRT technique, whereas there was no difference for the contralateral MLD between the two techniques. All patients received radiation were found to have lung fibrosis and were classified as grade 1-2 radiation pneumonitis. The quality of life was increased from score 2. 83 to 3.76. Conclusion： MPM is moderately sensitive to radiation. The flexible 3DCRT technique is feasible in the treatment of MPM and lung damage is reduced apparently comparing with the CRT technique. The quality of life of patients with MPM is improved after irradiation.