低位直肠癌拖出式适形切除术肠壁侧切缘安全距离的初步探讨

Preliminary investigation of intramural lateral spread distance in pull-through conformal resection of low rectal cancer

目的：探讨低位直肠癌肠壁侧方浸润距离，为拖出式适形切除术（PTCR）肠壁侧切缘的安全距离提供理论依据。方法收集2015年12月至2016年3月期间在上海第二军医大学附属长海医院肛肠外科因直肠癌行低位前切除术（LAR）或经腹会阴联合切除术（APR）患者的手术标本，经10％甲醛固定24 h后，分别在肿瘤标本顺时针走行的3、5、7和9点处，以肿瘤边界为原点，向外呈辐射状切取长度为1．5 cm，宽度为0．5 cm大小的正常肠管全层组织，测量肿瘤侧方浸润的距离并分析其影响因素。结果共收集到83例手术标本，总体侧方浸润率为71．1％（59／83），其中3、5、7和9点处，侧方浸润率分别为34．9％（29／83）、26．5％（22／83）、32．5％（27／83）和37．3％（31／83），差异无统计学意义（字2＝2．4449，P＝0．4853）。肿瘤的3、5、7、9点侧方浸润距离的中位数（四分位间距）分别为0（1．00）、0（0．50）、0（0．55）及0（1．00） mm；4个点位的第5百分位数（P5）均为0 mm，4个点位的第95百分位数（P95）分别为2．5、1．6、2．6和2．5 mm，各点位间浸润距离差异无统计学意义（字2＝5．3310，P＝0．1489）。 T1、T2、T3和T4期肿瘤侧方浸润率分别为0／4、58．3％（14／24）、83．0％（44／53）和1／2，差异有统计学意义（P ＝0．0050）。多因素回归分析显示，肿瘤T分期是肿瘤发生侧方浸润的独立危险因素（P ＝0．0022， OR ＝3．741，95％ CI：1．606～8．716）。结论低位直肠癌存在肠壁侧方浸润， T分期是其独立危险因素；施行PTCR时肠壁的斜行切除线距肿瘤边缘至少5 mm可保证侧切缘阴性。

Objective To investigate the intramural lateral spread distance in low rectal cancer in order to provide basis for safety lateral resection margin of pull-through conformal resection （PTCR）. Methods The patients with low rectal cancer who received low anterior resection or abdominal-perineal resection in Changhai Hospital from December 2015 to March 2016 were enrolled and Surgical specimens were collected. After the specimens were fixed in 10% formaldehyde for 24 hours , a piece of tissue that was 1.5 cm in length and 0.5 cm in width from the edge of tumor was cut. The tissue was obtained in the direction of 3, 5, 7 and 9 o′clock clockwise. The distance of intramural lateral spread was measured in the specimens and the risk factors were analyzed. Results A total of 83 specimens were collected and the overall proportion of intramural lateral spread was 71. 1%（59/83）. The rate of lateral spread from 3 to 9 o′clock was 34.9%（29/83）, 26.5%（22/83）, 32.5%（27/83） and 37.3%（31/83） respectively, and the difference was not statistically significant（χ2=2.444 9,P=0.485 3）.The median distance of lateral spread in each direction was all 0 mm and the quartile range was 1 mm , 0.5 mm, 0.55 mm and 1 mm respectively. The 5th percentile （P5） of each direction was all 0 mm and the 95th percentile（P95） of each direction was 2.5 mm, 1.6 mm, 2.6 mm, 2.5 mm, respectively and the difference was not statistically significant either （χ2=5.331 0, P=0.148 9）. The rate of lateral spread of T1, T2, T3 and T4 was 0/4, 58.3%（14/24）, 83.0%（44/53） and 1/2 respectively, and there was significant difference （P=0.005 0）. The multivariate analysis indicated that T stage （P=0.002 2, OR = 3.741, 95% CI： 1.606-8.716） was the risk factor of intramural lateral spread. Conclusions The intramural lateral spread does exist in low rectal cancer and T stage is the risk factor of lateral spread. The lateral resection margin should be 5 mm from the tumor edge at least when PTCR is performed.