139例鼻咽癌调强放疗的临床研究

Clinical study of 139 nasopharyngeal carcinoma patients for intensity modulated radiation therapy

目的 观察调强放疗（IMRT）鼻咽癌的临床疗效、急性反应和晚期损伤。方法 初治鼻咽癌患者139例中，Ⅰ期9例，Ⅱ期30例，Ⅲ期71例，Ⅳa期29例；97例单纯根治性放疗，42例放化综合治疗。将鼻咽和颈部的靶体积划分为鼻咽大体肿瘤体积（GTVnx）、颈部大体肿瘤体积（GTVnd）、临床靶体积1（CTV1）和临床靶体积2（CT2）。GTVnx、GTVnd、CTV1、CTV2处方剂量分别为68、60-66、60、54Gv，均30分次。鼻咽和上颈部靶体积采用IMRT技术照射，下颈部靶体积采用下颈前野常规照射。采用Kaplan-Meier法进行生存分析，RTOG／EORTC标准评价急性反应和晚期损伤。结果 中位随访时间19个月，1、2,3年局部区域无进展和无远处转移生存率及总生存率分别为97．8％、94．4％、94．4％和90．8％、86．4％、81．0％及94．5％、91．0％、85．6％。多数患者仅表现为1～2级急性反应和0～1级晚期损伤，未观察到4级急性反应和晚期损伤。对随访超过2年的48例患者口干症状的动态观察表明，随着治疗后时间的延长口干逐渐减轻。DVH分析显示IMRT提高了靶体积照射总剂量和分次剂量，减少了危及器官受照总剂量和分次剂量。结论 IMRT初治鼻咽癌可获得理想的局部区域控制，对正常组织器官有较好的保护作用。远处转移是治疗失败的主要原因。

Objective To verify the efficiency of nasopharyngeal carcinoma（NPC） treated with intensity modulated radiation therapy（IMRT） and to observe the acute and late normal tissue toxicities. Methods Between Jan. 2001 and Feb. 2004, 139 patients with nasopharyngeal carcinoma underwent IMRT at the Sun Yat-sen University Cancer Center. There were 27 females and 112 males, with a median age of 43 （range 19-73）. According to the Fuzhou Staging Classification, 9 patients had stage I 8,30 stage 11 , 71 stage m, and 29 stage IVa lesion. Ninety-seven patients received radical radiotherapy alone while 42 patients had cisplatin and 5-tluomumcil chemotherapy before, during and after radiotherapy. The prescription dose was engaged to the gross target volume （GTVnx） of nasopharyngeal to Dr68 Gy/3Of, positive neck lymph nodes（GTVnd） to Dr 60-66 Gy/30f, clinical target volume 1 （ CTVt ） to 60 Gy/30f, and CTV2 to 54 Gy/30f. The GTVnx, CTV1 and upper neck were irradiated by IM RT technique. The lower neck and the supraclavicular fussae were irradiated with the conventional technique using an anterior fieM. IMRT technique was camed out using an inverse planning system（CORVUS 3.0,Peacock plan, NOMOS）. Treatment was delivered with the Multi-leaf Intensity Medulating Collimator through a slice-by-slice arc rotation approach. The Kaplan-Meier method was to calculate the local-regional progression-free rate, distant metastasis-free rate, and overall survival. Acute and late toxicities were graded according to RTOG radiation morbidity scoring criteria. Results With a median followed-up of 19 months（range 6-40）, no patient developed any recumence at the primary site, however, three patients failed in the neck. Fifteen patients developed distant metastasis. The 1-, 2-, 3-year estimated local-regional progression-free survival rates, distant metastases-free survival rates and overall survival rates was 97.8%, 94.4%, 94.4%;90.8%, 86.4%, 81.0% ;and 94.5%,91.0%, 86.6%, respectively. Most of the patients had grade 1 to 2 acute and Grade 0 to 1 late toxicities, without anyone having Grade 4 acute or late toxicities. Xerestomia decreased with time in 48 evaluable patients. Analysis of the DVH strongly shows that IMRT can improved the total dose and dose per fraction to the larget volume with signifieant sparing of the normal structures at the same time.Conclusions lntensity modulated radiation therapy is able to improve local-region control and protect the nomal tissue in the treatment of NPC.Distant metastasis is the main cause failure.