宫颈癌常规放疗联合腔内三维放疗的初步研究

目的 探讨体外放疗联合CT影像为基础近距离放疗的宫颈癌患者DVH参数和治疗结果间关系。方法 2008—2011年间18例接受根治性放疗的Ⅱ_B—Ⅲ_B期宫颈癌患者进行了常规放疗加CT为基础的近距离三维放疗。观察两种放疗相加的高危CTV的D₉₀和直肠、膀胱的D_{2 cm³} 、D_{1 cm³} ,采用EQD₂进行剂量叠加。同时随访患者不良反应。结果 A点剂量为(93.0±5.5) Gy,高危CTV D₉₀为(73.6±11.9) Gy。患者中位随访时间为26个月,无复发病例。8例患者出现轻中度直肠晚期反应,其直肠D_{2 cm³} 、D_{1 cm³} 均高于无反应者(87.4±3.8) Gy∶(75.8±7.4) Gy,P=0.004;(96.4±6.6) Gy∶(80.5±7.1) Gy,P=0.001]。结论 CT引导的宫颈癌三维近距离放疗高危CTV D₉₀剂量比文献报道略低,直肠D_{2 cm³} 建议<75 Gy。

Preliminary study on relationship between DVH parameters and late side effects of rectum in external-beam radiotherapy combined with CT-based brachytherapy for locally advanced cervical cancer

Objective To investigate the relationship between dose-volume histogram (DVH) parameters and the late side effects (LSE) of the rectum in external-beam radiotherapy combined with computed tomography (CT)-based brachytherapy for locally advanced cervical cancer. Methods From 2008 to 2011, 18 patients with stage II_B-III_B cervical cancer received external-beam radiotherapy and CT-based brachytherapy. The DVH parameters of high-risk clinical target volume (HR CTV) D₉₀, point A dose, and D_{1 cm³} and D_{2 cm³} of the rectum and bladder were calculated by Oncentra HDR treatment planning system. Survival outcomes were followed up and rectal LSE were evaluated by RTOG/EORTC grades. Results The point A dose and HR CTV D₉₀ were (93.0±5.5) Gy and (73.6±11.9) Gy, respectively. The median follow-up was 26 months. No recurrence was found during follow-up. Eight patients had mild and moderate rectal LSE, and their rectum D_{2 cm³} and D_{1 cm³} were significantly higher than those of patients without mild and moderate rectal LSE (D_{2 cm³} :(87.4±3.8) Gy vs. (75.8±7.4) Gy, P=0.004;D_{1 cm³} :(96.4±6.6) Gy vs. (80.5±7.1) Gy, P=0.001). Conclusions HR CTV D₉₀ in CT-based brachytherapy for locally advanced cervical cancer might be lower than that in the MRI-based plan. Rectum D_{2 cm³} is recommended to be less than 75 Gy.