膀胱不同充盈状态下宫颈-宫体ITV在宫颈癌VMAT中的应用研究

目的探讨膀胱不同充盈状态下宫颈-宫体内靶区(ITV)在宫颈癌容积调强弧形治疗(VMAT)中的应用,期望获得更精确的宫颈癌调强放疗的计划靶区(PTV)。方法选取未手术宫颈癌放疗患者62例,随机分为研究组和对照组各31例。研究组采用膀胱3种充盈状态下的定位CT获得个体化的ITV、PTV与统一外放PTV进行VMAT对比,分析两组患者靶区及靶区内危及器官(OARs)的体积差异。比较两组CBCT验证中靶区脱出情况、放疗不良反应及近期疗效。结果两组靶区及靶区内OARs的体积相近(P>0.05);研究组子宫脱出PTV率、脱出PTV体积显著低于对照组(P<0.05);两组患者急性放疗不良反应相近(P>0.05);1、2年总生存、无进展生存率相近(P>0.05)。研究组、对照组子宫复发为1、2例。结论采用膀胱不同充盈状态下宫颈-宫体个体化的ITV、PTV进行宫颈癌根治性VMAT能提高靶区精确性,从而提高局部控制。

Application of cervix-uterine ITV in volumetric modulated arc therapy for cervical cancer under different bladder filling status

Objective To investigate the clinical application of cervix-uterine internal target volume (ITV) in volume-modulated arc therapy (VMAT) for cervical cancer under different bladder filling conditions, aiming to obtain more accurate planning target volume (PTV). Methods Sixty-two patients with cervical cancer receiving radiotherapy rather than surgery were selected and randomly divided into the study (n=31) and control groups (n=31). In the study group, individualized ITV, PTV and PTV margin were obtained under three bladder filling status by localization CT scan to compare the VMAT. The target area and organs at risk (OARs) within the target area were statistically compared between two groups. The target missing rate in CBCT, adverse events and short-term efficacy of radiotherapy were analyzed in two groups. Results There was no significant difference in the volume of target area and OARs in the target area between two groups (both P>0.05). In the study group, the target missing rate and target missing volume were significantly lower compared with those in the control group (both P<0.05). There was no significant difference in the incidence of acute radiation-induced adverse events between two groups (P>0.05). The 1-, 2-year overall survival and progress-free survival did not significantly differ between two groups (all P>0.05). One patient in the study group had uterine recurrence and 2 cases in the control group. Conclusion Application of individualized cervix-uterine ITV and PTV in definitive VMAT under different bladder filling conditions can improve the accuracy of target area contouring and improve the local control rate in cervical cancer patients.