Oncologic safety of transverse colon cancer surgery without central vessel ligation.

Abstract

108 Background: Transverse colon cancers (TCC) have mixed embryological and molecular characteristics of right and left colon cancers and they are difficult to classified to right or left colon cancer due to the ambiguity of their location. Therefore, there is a lack of research about TCC alone, and it tended to be excluded in previous large clinical trials. Also, the optimal surgical procedure for each TCC varies depending on the location and stage of the tumor and anatomic structure of the patient. Consequently, standardization of surgery for TCC has not been established, and the oncologic benefits of central vessel ligation (CVL) with complete mesocolic excision and D3 dissection are unclear yet. The aim of the study is to evaluate oncologic safety of TCC surgery without CVL of middle colic artery. Methods: It is a retrospective, observational study. The clinical, surgical, and pathological characteristics were investigated retrospectively and statistical analyses were performed using chi-square test, independent samples T-test, and Kaplan-Meier analysis. Mid TCC was defined as tumor arising in the middle third of transverse colon and determined by intraoperative exploration. Hepatic and splenic flexure colon cancer, which were defined as tumor is adjacent to liver or spleen, were excluded. Radical resection was conducted along the embryological surgical plane, following D2 or D3 dissection. Central vessel ligation was defined as ligation of root of middle colic artery. Results: The numbers of proximal, mid, and distal TCC were 48 (45.3%), 32 (30.2%), and 26 (24.5%), respectively. The numbers of right hemicolectomy, transverse colectomy and left hemicolectomy were 57 (53.8%), 28 (26.4%) and 21 (19.8%). The numbers of No CVL group and CVL group were 47 (44.3%) and 59 (55.7%). The numbers of stage I, II and III were 24 (22.6%), 45 (42.5%), 37 (34.9%), and 49 patients underwent adjuvant treatment. The most frequent organ of recurrence was peritoneum (N=6, 5.6%). There was no statistically significant difference of stage, mean number of retrieved lymph node (24.12 vs. 22.36 p=0.464), mean number of metastatic lymph node (1.53 vs. 0.74, p=0.163), mean proximal margin (19.2 cm vs. 16.7 cm, p=0.139), mean distal margin (9.6 cm vs. 9.9 cm, p=0.753), adjuvant chemotherapy, and the rate of recurrence with lymph node metastasis. Also, there was no statistically significant difference of 6-year DFS survival and OS in stage II and III. Conclusions: When following oncologic plane and adequate lymph node dissection, resection without CVL for TCC is considered to have equal surgical and oncologic outcomes comparing to resection with CVL. Therefore, it is considered that CVL would not be always mandatory for TCC surgery, and a branch of middle colic artery could be preserved, if necessary.