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PWE-339 Colorectal cancer resection – lap or open: is the same amount being removed?

Introduction A surrogate marker of the quality of colorectal cancer resection is the number of lymph nodes harvested from the specimen. Recent attention has focused on the completeness of mesenteric resection in order to maximise lymph node clearance. Laparoscopic resection, where feasible, is accepted as the preferred approach, but concern remains as to the oncologic adequacy of resection compared to traditional open surgery. The aim of this study was to compare colorectal cancer specimens removed by laparoscopic resection with open surgical specimens, as regards lymph node harvest and extent of mesenteric resection. Method A consecutive series of 282 consecutive open and laparoscopic colorectal cancer resections, performed by 5 colorectal surgeons, was studied. 78 patients undergoing Hartmann’s or abdomino perineal resection, subtotal colectomy or proctocolectomy were excluded. Pathological examination of the excised specimen was performed by one of 3 colorectal pathologists to a standard protocol. Distance from the tumour to the high tie and number of lymph nodes harvested was recorded for each specimen. Results 204 patients (109 male) were included in the analysis. Tumours were divided into 3 groups: right hemi colectomy (82), left hemi colectomy (43) and anterior resection (79). For right sided tumours (32 laparoscopic, 50 open), mean distance to high tie was 87.5 mm for laparoscopic resection and 78.6 mm for open resection (p = 0.07). Mean lymph node harvest was 17.0 nodes laparoscopically compared to 21.8 nodes for open resection (p = 0.008). For left sided tumours (10 laparoscopic, 33 open), mean distance to high tie was 105.2 mm for laparoscopic resection and 102.7 mm for open resection (p = 0.41). Mean lymph node harvest was 18.1 nodes laparoscopically compared to 20.6 for open resection (p = 0.14). For rectal tumours (32 laparoscopic, 47 open), mean distance to high tie was 130.6 mm for laparoscopic resection and 131.5 mm for open resection (p = 0.49). Mean lymph node harvest was 18.1 nodes laparoscopically compared to 21.5 nodes for open resection (p = 0.009). More patients undergoing open resection for rectal cancer patients underwent pre-operative neo-adjuvant treatment (laparoscopic 4/32, 12.5%; open 11/47, 23.4%). Conclusion This study indicates that there is no significant difference in the extent of mesenteric resection between open and laparoscopic colectomy specimens from any of the three sites. However, despite comparable lengths of mesenteric resection, significantly more lymph nodes were removed by open resection compared to laparoscopic resection of right sided and rectal tumours. Disclosure of interest None Declared.