OBJECTIVETo verify the clinical safety of complete mesocolic excision (CME) and manufacture pathological large slices.

METHODSA prospective analysis clinical data of 85 right colon cancer in patients by the same group of surgeons at the Department of General Surgery, Beijing Friendship Hospital, Capital Medical University from January 2012 to December 2013 which were divided into two groups: CME group (n=39) and traditional radical operation group (n=46) by surgical approach. CME group and control group were compared the differences of clinic and pathologic variables, precise tissues morphometry, lymph nodes harvest, mesocolic area and so on. By comparison to operation time, blood loss, postoperative complications, flatus restoring time, drainage removal time and length of stay, the security of CME was analyzed. Statistical methods included independent sample t-test, Wilcoxon rank sum test and χ(2) test. In order to manufacture pathological large slices, the CME operation specimens were fixed. The large slices were stained by routine HE staining to detection of circumferential resection margin.

RESULTSMean number of total lymph nodes was increased obviously in CME group (26.8±1.9 vs. 23.2±3.4, t=4.261, P=0.000). Mean number of lymph nodes of stage Ⅰ, Ⅱ were different between two groups (25.8±3.6 vs. 18.2±4.5, 26.8±7.7 vs. 24.9±6.2, t=8.776, 2.802, P=0.000). The positive lymph nodes of CME group was higher than control group (4(7) vs. 1.5(2), P=0.032), above all with statistically significant difference. Comparing CME group with the control group, there were the larger area of mesentery ((15 555±1 263) mm(2) vs. (12 493±1 002) mm(2,) t=12.456, P=0.000), the greater distance between the tumor and the high vascular tie ((116±22) mm vs. (82±11) mm, t=9.295, P=0.000), the greater distance between the normal bowel and the high vascular tie ((92±17) mm vs. (74±10) mm, t=8.132, P=0.000) of CME, with statistically significant difference. There were no statistically significant differences from operation safety when CME group was compared with the control group. The pathological large slices of colon cancer were prepared successfully and dyed evenly than those large slices were used to observe whether the lymph tube and lymph node metastasis inside the mesocolon. Existence of direct tumor invasion could be confirmed by investigating the large slices. Cancer embolus in intravascular and micro infiltration in mesocolon also could be found.

CONCLUSIONSCME operation can get the standard excision according the mesocolic area and integrity, as well as to harvest the maximum number of lymph node. The clinical application of CME is safe and does not increase the risk of operation. Circumferential resection margins can be detected by pathological large slices.