术前三维适形放疗与容积调强弧形治疗同期联合化疗在局部进展期直肠癌中应用的近期效果比较

Short-term efficacy comparison between preoperative three dimensional conformal radiotherapy and volumetric modulated arc therapy concurrently combined with chemotherapy in the treatment of locally advanced rectal carcinoma

目的比较术前三维适形放疗（3D-CRT）及容积调强弧形治疗（VMAT）同期联合化疗用于局部进展期直肠癌（LARC）的近期临床疗效及治疗相关不良反应。方法回顾性收集2007年5月至2013年4月在中山大学肿瘤防治中心接受术前3D-CRT或VMAT联合同期化疗（主要为Xelox方案：卡培他滨加奥沙利铂）及手术的334例LARC患者的临床资料，其中3D．CRT组172例，VMAT组162例。VMAT组靶区处方剂量：计划靶区1（PTV1）50Gy／2Gy×25F，PTV246Gy／1．84Gy×25F；3D-CRT组处方剂量PTV：46Gv／2．0Gy×23F。两组放化疗期间患者急性不良反应评价参照CTCAE3．0标准。比较两组放化疗期间不良反应发生情况、手术治疗情况、术后并发症及术后病理分期等近期疗效情况。结果两组基线资料的比较，除肿瘤下缘距肛缘的距离差异具有统计学意义外（P=0．009），其他差异均无统计学意义（均P〉0．05）。全组中位放疗剂量46（45～70）Gy；3D-CRT与VMAT组放疗中断率的差异无统计学意义[1．7％（3／172）比1．2％（2／162），P=1．000]；同期放化疗期间，两组间2级和3级血液学不良反应以及3级非血液学不良反应发生率的比较，差异均无统计学意义（均P〉0．05），但2级非血液学不良反应中，VMAT组患者出现放射性皮炎和手足综合征的概率高于3D．CRT组[分别为25．9％（42／162）比10．5％（18／172），P=0．000；3．7％（6／162）比0，P=0．012]。两组均无任何4级放化疗不良反应发生。两组患者肿瘤凡切除、手术方式、保肛率、手术持续时间以及术后并发症发生率的差异均无统计学意义，术后病理T分期、N分期、TNM分期及术后病理完全缓解率（pCR）率的比较，差异亦无统计学意义（均P〉0．05）。但相比3D．CRT组，VMAT组术中平均失血量更少[（114．6±100．0）ml比（169．0±143．9）ml，P=0．000]，中位住院时间更短[16（8～84）d比20（10～47）d，P=0．000]。两组均无术后30d内死亡患者。结论与3D-CRT技术相比，VMAT技术应用于直肠癌术前放疗并不能减少近期治疗相关不良反应，也未能提高短期疗效。

Objective To compare the short-term efficacy and treatment-related adverse reaction between preoperative three dimensional conformal radiotherapy （3D-CRT） and volumetric modulated arc therapy （VMAT） concurrently combined with chemotherapy in the treatment of locally advanced rectal carcinoma （LARC）. Methods Clinical data of 334 patients with LARC undergoing preoperative 3D- CRT（ 172 cases） or VMAT（ 162 cases） with concurrent Xelox chemotherapy （main protocol： capecitabine plus oxaliplatin） and surgery in Sun Yat-sen University Cancer Center from May 2007 to April 2013 were retrospectively analyzed. The total radiation dose of VMAT group was： 50 Gy/2.0 Gy per fraction×23 fractions for planning target volume 1 （FFV1） and 46 Gy/1.84 Gy per fraction × 25 fractions for PTV2; the total radiation dose of 3D-CRT group was： 46 Gy/2.0 Gy per fraction x 23 fractions for PTV. The treatment-related adverse reaction of both groups during chemoradiotherapy was measured according to the criteria of Common Terminology Criteria for Adverse Events v3.0 （CTCAE 3.0）. Rate of adverse reaction and short-term efficacy between 3D-CRT and VMAT group were compared, in terms of radiotherapy break, hematological and non-hematological toxicity, average duration of surgery and perioperative hospitalization, intraoperative blood loss, surgical procedures, R0 excision, sphincter preservation, postoperative complications, pathological complete response （pCR）, and postoperative pathological staging. Results There were no significant differences in baseline clinical parameters between 3D-CRT and VMAT group （all P 〉 0.05）, except for the distance from lower tumor margin to anal verge （P = 0.009）. The median radiation dose for all the patients was 46 （45 to 70） Gy. There was no significant difference in the rate of radiotherapy cessation between 3D-CRT and VMAT group [1.7% （3/172） vs. 1.2% （2/162）, P= 1.000]. During concurrent chemotherapy, incidences of grade 2 to 3 hematological toxicities, grade 2 diarrhea, and grade 3 non-hematological toxicities were not significantly different （all P 〉 0.05）, while in grade 2 non-hematological toxicities, ratio of radiodermatitis and hand-foot syndrome was higher in VMAT group as compared to 3D-CRT group [25.9%（42/162） vs. 10.5%（18/172）, P=0.000; 3.7%（6/162） vs. 0, P= 0.012]. There was no grade 4 adverse event in both groups. Surgical procedure, average duration of surgery, R0 excision, anus preservation, postoperative complications, pCR, and postoperative pathological staging were not significantly different （all P 〉 0.05）. As compared to 3D-CRT group, VMAT group had less intraoperative blood loss [（114.6 ± 100） ml vs. （169 ±143.9） ml, P 〈 0.001] and shorter perioperative hospitalization [ 16（8 to 84） d vs. 20（10 to 47） d, P〈 0.001 ]. There was no death case in two groups within 30 days after operation. Conclusions Compared with 3D-CRT technique, preoperative VMAT technique can not significantly reduce the incidence of treatment-related adverse reaction and improve the short-term efficacy in the treatment of LARC.