局部晚期直肠癌同步放化疗前后MRI参数与预后相关性研究

Correlation analysis between MRI parameters and prognosis in locally advanced rectal cancer patients receiving chemoradiotherapy

目的探索局部晚期直肠癌术前同步放化疗前后MRI指标与预后关系。方法回顾分析2015-2017年间在中国医学科学院肿瘤医院初治局部晚期直肠癌患者,具有放疗前、后MRI且接受手术且随访资料完整患者96例,均接受术前长程同步放化疗,放疗后6~13周接受根治性手术。对放化疗前4周内及之后4~8周的直肠MRI进行评价,并与3年无瘤生存(DFS)率进行相关分析。结果全组患者T3、T4期者分别为80例(83%)、16例(17%),N0、N1-2期者分别为14例(15%)、82例(85%),直肠系膜筋膜受侵[MRF(+)]者69例(72%),肠壁外血管侵犯[EMVI(+)]者58例(60%)。全组患者接受术前放疗中位剂量为50 Gy,均接受同步化疗增敏。同步放化疗后T分期降期率及N分期转阴率分别为24%和50%,MRF(+)率、EMVI(+)率分别降至37%(P<0.001)和27%(P<0.001)。单因素及多因素分析均显示放化疗后MRI显示N分期、EMVI状态转变与患者3年DFS相关(P<0.05)。结论同步放化疗后MRI显示EMVI持续阳性、N1-N2期是DFS预后不良因素,提示改进治疗的必要性。

Objective To investigate the relationship between MRI parameters and clinical prognosis before and after chemoradiotherapy in patients with locally advanced rectal cancer.Methods Clinical and follow-up data of 96 patients with locally advanced rectal cancer who were initially treated in the Cancer Hospital of Chinese Academy of Medical Sciences from 2015 to 2017 were retrospectively analyzed.All patients received preoperative chemoradiotherapy,followed by delayed radical surgery at 6-13 weeks after radiotherapy.MRI assessment was performed twice around radiotherapy which were within 4 weeks before the treatment and 4-8 weeks after it.Correlation analysis was utilized to determine the association between MRI assessment and 3-year disease-free survival(DFS).Results Of the all patients,80(83%)had T3 stage,16(17%)had T4 stage,14(15%)had N0 stage,and 82(86%)had N1-2 stage.Among them,69(72%)and 58(60%)patients were positive for MRF and EMVI.The median dose of radiotherapy was 50Gy,and all patients were sensitized by simultaneous capecitabine.After chemoradiotherapy,T-downstage rate of the whole group was 24%,and 50%for the N-downstage rate.The MRF-and EMVI-positive rates were significantly decreased to 37%and 27%after chemoradiotherapy(both P<0.001).Univariate and multivariate analyses showed that N staging and EMVI status change were significantly correlated with the 3-year DFS.Conclusion MRI after concurrent chemoradiotherapy reveals that positive EMVI throughout the treatment and N1-N2 staing are poor prognostic factors of DFS,suggesting the need for improving the treatment.