新辅助放化疗对mr T_3期低位直肠癌患者不同浸润深度远期疗效的影响

Long- term outcome of neoadjuvant chemoradiotherapy based on the depth of invasion in mr T3 low rectal cancer

目的：探讨新辅助放化疗（neoadjuvant chemoradiotherapy,CRT）对c T3期低位直肠癌及其各亚分期预后的影响,进一步评估是否所有T3期低位直肠癌患者均应行CRT。方法：对2008年1月至2012年12月间福建医科大学附属协和医院结直肠外科收治的223例c T3期低位直肠癌患者,按北美放射协会（RSNA）影像学分期标准回顾性进行亚分期,即根据高分辨率MRI测量下肿瘤浸润直肠系膜的深度（depth of mesorectal invasion,DMI）分为mr T3a期（DMI〈5 mm）,mr T3b期（DMI为5~10 mm）和mr T3c期（DMI〉10 mm）,并根据是否行CRT分为新辅助放化疗组（CRT组,115例）和未行新辅助放化疗组（n CRT组,108例）,比较两组患者及其各亚分期（mr T3a、mr T3b、mr T3c）之间预后的差异。结果：对于整体mr T3期,CRT组和n CRT组的3年无病生存率（78.2%vs.71.9%,P=0.608）和局部复发率（4.4%vs.8.5%,P=0.120）无统计学差异。对于mr T3各亚分期,CRT组和n CRT组预后分别为：mr T3a：3年无病生存率82.4%vs.81.8%（P=0.837）、局部复发率5.8%vs.5.9%（P=0.658）;mr T3b：3年无病生存率84.4%vs.42.4%（P=0.032）、局部复发率0 vs.18.2%（P=0.014）;mr T3b、mr T3c：3年无病生存率72.8%vs.42.4%（P=0.060）、局部复发率2.4%vs.18.2%（P=0.021）。单因素分析提示DMI和环周切缘（circumferential resection margin,CRM）是mr T3期直肠癌患者3年无病生存时间的影响因素,Cox风险回归模型多因素分析提示CRM是独立影响因素（OR=2.249,CI：1.067~4.742,P=0.033）。结论：CRT能改善mr T3b、mr T3c期低位直肠癌患者的预后,但可能无法改善mr T3a且CRM阴性低位直肠癌患者的预后,对这部分患者可直接行手术治疗。

Objective： To investigate the prognosis of c T3 and the subgroups of low rectal cancer patients who underwent neoadjuvant chemoradiotherapy（CRT） and evaluate whether all patients with c T3 low rectal cancer should undergo CRT. Methods： A total of223 patients with c T3 low rectal cancer treated in the Department of Colorectal Surgery of Fujian Medical University Union Hospital from January 2008 to December 2012 were divided into neoadjuvant chemoradiotherapy group（CRT group）（115 cases） and no neoadjuvant chemoradiotherapy group（n CRT group）（108 cases） according to whether the patients underwent CRT. Afterward, the patients were retrospectively divided into three subgroups（mr T3 a, mr T3 b, and mr T3c） according to the proposed criteria of the Radiologic Society of North America（RSNA） by measuring the depth of mesorectal invasion（DMI）（DMI5, DMI=5-10, and DMI10 mm）. The prognoses of the two groups and their subgroups were compared. Results： The CRT and n CRT groups revealed no significant differences in the 3-year disease-free survival rate and the local recurrence rate for all the mr T3 patients（78.2% vs. 71.9%, P=0.608; 4.4% vs. 8.5%, P=0.120） and mr T3 a patients（82.4% vs. 81.8%, P=0.837; 5.8% vs. 5.9%, P=0.658）. On the contrary, for the mr T3 b patients, the CRT and n CRT groups revealed significant differences in the 3-year disease-free survival rate（84.4% vs. 42.4%, P=0.032） and local recurrence rate（0.0% vs. 18.2%, P=0.014）. For the mr T3 b,c patients, the CRT and n CRT groups revealed no significant difference in the 3-year disease-free survival rate（72.8% vs. 42.4%, P=0.060） but revealed a significant difference in the local recurrence rate（2.4% vs. 18.2 %, P=0.021）. COX regression analysis was utilized for 3-year disease-free survival, DMI and circumferential resection margin（CRM） were significant in the univariate analysis. Additionally, the multivariate analysis indicated that CRM is an independent impact factor（OR=2.249, CI 1.067-4.742, P=0.033）. Conclusion： CRT can improve the prognosis of patients with mr T3 b,c low rectal cancer but may not significantly influence the prognosis of patients with mr T3 a and CRM-negative low rectal cancer; surgical treatment can be performed in these patients without CRT.