低位直肠癌术前加速超分割适形放疗加同步化疗的临床观察

Results of preoperative accelerated hyperfractionated conformal radiotherapy plus concurrent chemotherapy for low rectal cancer

目的分析术前加速超分割适形放疗加同步化疗对低位直肠癌的治疗结果,探讨其放化疗模式的可行性及有效性。方法42例低位直肠癌患者入组该研究,所有患者均经病理证实为直肠腺癌,治疗前均行CT、MRI及直肠内超声检查,临床分期为T2～3N0M0。放疗靶体积为GTV基础上外放3～5cm,每次150cGy,每日2次,2次放疗间隔时间≥6h,连续治疗14d,总剂量4200cGy。同时口服卡培他滨化疗（1250mg/m^2,每天2次,连续治疗14d）。放化疗结束后3～4周进行手术,手术均行全直肠系膜切除术（TME）。结果总有效率为90.5%,其中完全缓解率为50.0%,部分缓解率为40.5%;直肠内超声及MRI证实降期率为76%（32/42）,术后病理降期率为69%,保肛率为76%。生存及局控时间从放射治疗开始之日算起,3年局部控制率为93%,无病生存率为89%。3级急性毒副反应（放射性直肠炎）仅为9%,腹泻2%,中性粒细胞减少1%,乏力3%,手足综合征4%。结论低位直肠癌术前加速超分割适形放疗加同步口服卡培他滨化疗可以有效地缩短治疗疗程,能够显著地降低肿瘤的临床分期,提高了手术切除率及保肛率。

Objective To evaluate results of preoperative accelerated hyperfractionated conformal radiotherapy plus concurrent chemotherapy for low rectal cancer,and to discuss chemoradiotherapy feasibility of pattern and efficiency.Methods Forty-two patients （ 27 males,15 females;age range,42～65 years） were enrolled in the study.All patients had pathology-demonstrated invasive adenocarcinoma of the rectum,clinic stage of patients were T2～3N0M0.All patients underwent an endorectal ultrasound,CT and MRI scan.Radiotherapy was delivered to a clinic target volume （CTV） including the gross tumor volume （GTV） plus 3～5 cm margin,with a dose of 42 Gy （1.5 Gy twice daily with a minimum 6 h interval）.Concurrent chemotherapy was delivered （capecitabine 1 250 mg/m2,twice daily for 7 days/week for 14 days）.Surgical resection was performed between 3～4 weeks from the end of chemoradiotherapy.Using endorectal ultrasound and MRI measurements.Toxicity was evaluated on the basis of the Radiation Therapy Oncology Group （RTOG） criteria.Results The overall clinical response rate was 90.5,21 patients （50.0） had complete response（CR）,17 patients （40.5） had partial response （PR）, and the downstaging rate was 76 for endorectal ultrasound and MRI ,with postoperative pathologic complete response rate of 69.Sphincter preservation was achieved in 32 patients（76）.After chemoradiotheray.The grade 3 adverse events were radiation proctitis（9）,diarrhoea （2）,hand-foot syndrome （4）and fatigue （3）.No patient developed Grade 4 acute toxicity.3-year local control was 93 and disease-free survival was 89 for the group as a whole.Conclusions Preoperative chemoradiotherapy with concurrent oral capecitabine is safe and well tolerated in low rectal cancer patients.Efficiently shorten course of treatment,significantly achieved downstaging and improve surgical resection and sphincter preservation.