计划性调强放疗加腔内后装治疗早期鼻咽癌

Primary Study of Planning Intensity Modulated Radiation Therapy Combined with Intracavitary Brachytherapy for Early Stage of Nasopharyngeal Carcinoma

目的 分析计划性调强放疗(IMRT)加腔内高剂量率后装治疗早期鼻咽癌的剂量分布合理性和近期疗效. 方法 10例(T1-2 N0-1 M0,Ⅰ～Ⅱ期)鼻咽癌患者接受IMRT加腔内高剂量率后装治疗(观察组);计划性IMRT的处方剂量为:肿瘤靶区(GTV)60～62 Gy,高危临床靶区(CTV1)56～58 Gy,亚临床靶区(CTV2)50～54 Gy.外照射结束后休息1周左右,然后进行鼻咽腔内高剂量率后装治疗(250～300 cGy,每天2次,2～3 d)推量照射.另将该10例患者在相同治疗计划系统中模拟设计全程IMRT(GTV 66～70 Gy,CTV1 62～64 Gy,CTV2 54～56 Gy)进行自身对照研究(对照组).比较2组的物理剂量分布情况. 结果 观察组的肿瘤靶区所接受的照射绝对物理剂量明显高于对照组,观察组脑干、脊髓、腮腺、垂体正常器官受照射剂量明显低于对照组,2组差别有统计学意义(P=0.000).随访中位时间11月(4～17月),未发现局部复发或转移,并发症少. 结论 计划性IMRI加腔内后装治疗早期鼻咽癌患者可有效地提高肿瘤靶区的照射剂量,同时降低腮腺、脑干、脊髓和垂体等危险器官的照射剂量,其物理剂量分布更具合理性.

Objective To evaluate the rationality of physical dosage distribution and the recent treatment result of planning intensity modulated radiation therapy(IMRT) combined with intracavitary brachytherapy for early stage of nasopharyngeal carcinoma(NPC),and to study the rationality and the clinical application value.Methods[WTBZ] From January 2005 to May 2006,10 cases with stage T_(1-2)N_(0-1) NPC were treated with planning intensity modulated radiation therapy combined with intracavitary brachytherapy.The prescription dosage of study group included GTV 60～62 Gy,CTV_1 56～58 Gy,CTV_2 50～54 Gy;after a break of a week,the boost with high dose rate of intracavitary brachytherapy(250～300 cGy).The control group were whole course IMRT calculated in the treatment planning system(PLATO V(2.6.4))(GTV 66～70 Gy,CTV_1 62～64 Gy,CTV_2 54～56 Gy).The distribution of physical dose and clinical results were compared between the groups.Results The absolute physical dose of tumor target in study group was significantly higher than that in control group.The dosage in braim stem,spine cord,parotid gland and pituitary were much less than those in control group.The mean follow-up term was 11 months(4~17 months).There were no local recurrence and metastases,and there were less complications.Conclusion planning IMRT combined with intracavitary brachytherapy for early stage of NPC can effectively improve the dosage in tumor target,and can reduce the dosage in risk organs(such as stem,spine cord,parotid gland and pituitary);and the distribution of physical dosage was more rationality.Its clinical result and bio-effect was better than old type IMRT.