宫颈癌引导腔内联合组织间插植近距离放疗阴道模板的临床设计

Design of Transvaginal Cylindrical Templet for Combined Interacavitary/Interstitial Brachytherapy Treatment Based on Local Spread Patterns of Cervival Cancer

[目的]分析研究宫颈癌局部转移的精准影像解剖部位,设计制作普遍适用于宫颈癌宫旁远端转移患者的经阴道插植模板,引导腔内联合组织间插植近距离放疗。[方法]基于498例ⅡB~ⅣA期宫颈癌患者局部转移部位的影像解剖分析,以及盆腔外照射后肿瘤回缩变化,设计制作经阴道插植模板,应用于20例盆腔外照射后宫旁残留癌肿≥3cm的宫颈癌患者,引导腔内联合组织间插植近距离放疗。[结果] 498例局部晚期宫颈癌中,98.5%宫旁转移发生在盆隔之上、腹膜之下,在阴道上1/3处贴近阴道侧壁,在宫颈阴道两侧2~4点和8~10点之间,向上:依次沿阴道直肠韧带、骶韧带向侧后方蔓延,沿主韧带向侧前方蔓延,呈扇形逐步远离宫颈阴道侧壁达侧盆壁,发生宫旁远端转移。盆腔外照射后,97.5%宫旁残留癌肿距宫腔管的距离一侧≤3.5cm、另一侧≤2.5cm,上缘在宫颈内口水平,3%为前后极不对称癌肿。基于此解剖,设计一组经阴道圆柱体插植模板,周边8~10个直针孔,6~12点连线上3个宫腔管孔,在两侧壁2点~4点之间和8点~10点之间有1~2排斜孔。该阴道模板引导腔内联合组织间插植近距离放疗,初步应用于20例盆腔外照射后一侧宫旁残留癌肿>3cm或前后极不对称的宫颈癌患者:平均高危临床靶区体积(HR-CTV)(60.4±20.8)cm3;平均剂量HR-CTV D90 86.7Gy (EQD2α/β10),膀胱2cc 76.1Gy (EQD2α/β3),直肠2cc 68.7Gy (EQD2α/β3),乙状结肠2cc 65.9Gy (EQD2α/β3)。放疗后3月完全缓解(CR)18例、部分缓解(PR)2例,无3~4级急性期放疗并发症发生。[结论]该阴道插植模板设计合理,引导宫颈癌腔内联合组织间插植近距离放疗,操作简单,损伤小,可重复性好。对于盆腔外照射后宫旁残留癌肿≥3cm者,获得了更好处方剂量的HR-CTV靶区覆盖,较好保护危及器官。

[Objective]To design a novel transvaginal cylindrical templet for combined interacavitary/interstitial(IC/IS)brachytherapy(BT)based on local spread patterns of cervical cancer.[Methods]A transvaginal templet was designed based on local spread patterns of 498 patients with cervical cancer stageⅡB~ⅣA.The novel templets were used to perform IC/IS BT in 20 cervical cancer patients with insufficient response after external-beam radiotherapy(EBRT).[Results]In 498 patients with locally advanced cervical cancer,98.5%parametrial lesions were above the pelvic septum,spreading posterolaterally along rectovaginal ligament and uterosacral ligament,anterolaterally along cardinal ligament.It was fan-shaped away from both sides of cervix and vagina to the lateral pelvic wall.After 45 Gy EBRT,residual parametrial tumors of 97.5%cervical cancer patients were≤3.5 cm in one side and≤2.5 cm in other side,the upper margin at the level of the internal OS of the cervix.There were 3%patients with anteroposterior asymmetrical tumor.Based on the anatomy,the cylindrical templet was designed with peripheral straight holes,oblique needle holes and central tandem holes.In 20 patients treated with the new applicator,the total(EBRT+BT)D90 and the high risk clinical target volume(HR-CTV)were on average 86.7(SD2.4)Gyα/β10 and 60.4(SD20.8)cm3.The average D2 ccα/β3 of bladder and rectum and sigmoid were 76.1(SD2.7)Gy and 68.7(SD3.3)Gy and 65.9(SD5.4)Gy,respectively.Among20 patients there were 18 cases of complete remission and 2 cases of partial remission 3 months after treatment.[Conclusion]The transvaginal cylindrical templet guiding IC/IS is feasible in cervical cancer patients with distal parametria residual disease after EBRT,it increases total dose and coverage of HR-CTV without increasing the dose to organs at risk.