缩野调强放射治疗在中晚期子宫颈癌治疗中的应用价值

Application value of reduced field intensity modulated radiation therapy for advanced cervical cancer

目的探讨缩野调强放射治疗（RF-IMRT）用于中晚期子宫颈癌的临床疗效和价值。方法对2005年8月至2011年8月山东省肿瘤医院收治的71例ⅡB～IIIB期子宫颈癌患者行RF-IMRT（RF-IMRT组），具体放疗计划为先行全盆IMRT，给予处方剂量30Gy，然后缩野照射淋巴引流区、宫颈旁及宫旁组织，再给予处方剂量30Gy。同时对该组患者采用ADACPinnacle3计划系统拟设常规二野放疗计划，拟给予相同的处方剂量，比较危及器官的受照射剂量。选取同期收治的72例接受常规二野放疗计划患者作为对照（c-RT组），拟给予相同的处方剂量。两组患者均同时行后装治疗和同步化疗。比较两组患者的临床疗效、不良反应及危及器官的受照射剂量。结果全部患者均完成放疗计划，66例RF—IMRT组患者和65例c—RT组患者完成随访。RF—IMRT与拟行常规放疗计划比较，靶区更精确，剂量适形度明显增加（0．711±0．057和0．525±0．062，P=0．032），危及器官的受照射剂量明显减少[直肠：（41．6±6．8）Gy和（50．8±3．2）Gy，P=0．016；膀胱：（40．2±2．9）Gy和（51．4±1．8）Gy，P=0．007；小肠：（22．3±2．6）Gy和（35．8±3．9）Gy，P=0．004]。RF—IMRT组放射治疗计划靶区（HIV）内的平均剂量为60．8Gy，明显高于c—RT组（51．2Gy，P=0．006）。RF—IMRT组与c—RT组比较，急、慢性放疗不良反应的发生率明显降低（均P〈0．05），但有效率的差异无统计学意义（P〉0．05）。RF．IMRT组与c-RT组患者的1、3、5年生存率差异无统计学意义（P〉0．05），但RF—IMRT组患者的5年无进展生存率为65．2％，明显高于c—RT组（46．2％，P=0．039）。结论RF—IMRT技术可使中晚期子宫颈癌患者的靶区获得理想的剂量分布，肿瘤靶区及盆腔淋巴引流区均获得根治性剂量，邻近危及器官得到较好的保护，不良反应可以耐受，且可提高患者的5年无进展生存率。

Objective To explore the clinical value and efficacy of reduced field intensity modulated radiation therapy （RF-IMRT） for patients with advanced cervical cancer. Methods Seventy-one patients with stage IIB-IIIB cervical cancer, who underwent reduced field IMRT （RF-IMRT group） and 72 patients treated with conventional radiotherapy （c-RT group） in Shandong Cancer Hospital between 2005 August and 2011 August, were enrolled in this study. The RF-IMRT plans were as follows： whole pelvic IMRT plan was performed to deliver an initial dose of 30 Gy, then the irradiated volume was reduced to lymphatic drainage region as well as paracervix and parametrium for an additional 30 Gy boost. Conventional 2-field RT plan was performed in these patients using ADAC Pinnacle 3 planning system, to be given the same prescription dose, and to compare the irradiation dose of organs at risk （OARs）. At the same time, conventional 2-field RT was performed in 72 patients of the c-RT group. Concurrent chemotherapy and intracavitary brachytherapy were also performed in the two groups. The treatment response, toxicities, normal tissue avoidance, and survival were assessed. Results Sixty-six patients of the RF-IMRT group and 65 patients of the c-RT group fulfilled the treatment plan. IMRT plans yielded better dose conformity to the target （0. 711 ±0. 057 vs. 0.525±0. 062,P =0. 032） and better sparing of the rectum, bladder and small intestine （rectum： 41.6±6.8 vs. 50.8 ±3.2, P=0.016; bladder： 40.2±2.9 vs. 51.4±1.8, P=0. 007 ; small intestine ： 22.3 ± 2.6 vs. 35.8 ± 3.9, P = 0. 004）. The mean dose delivered to the planning target volume （PTV） was significantly higher in the RF-IMRT group than that in the c-RT group （60.8 vs. 51.2 Gy, P = 0. 006）. The RF-IMRT patients experienced significantly lower acute and chronic toxicities with comparable short-term effects than did those treated with conventional RT （P 〉 0.05）. No significant differences were found between the two groups for 1-, 3-, and 5-year overall survival （OS） rates, while a significantly higher progression-free survival （ PFS, 65.2% vs. 46.2%, P = 0. 031 ） rate was observed in the RF-IMRT group. Conclusions RF-IMRT yields higher dose distributions and lower toxicities compared with conventional RT, and both the tumor target volume and pelvic lymphatic drainage region achieve curative dose irradiation, the adjacent organs at risk are well protected, and with tolerable adverse reactions. Yet, RF-IMRT provides comparable clinical outcomes and higher PFS.