Predictors of Lymph Node Count in Left-Sided Colon and Rectal Cancer Resections


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Nikhil Lal1,Nikhil Lal1,Andrea Sheel2,Fran McNicol2,Ufuk Gur2,Richard Heath2,Paul Rooney2
1University of Liverpool,2The Royal Liverpool University Hopsital



Lymph node metastasis are a key prognostic factor for colorectal cancer. Current guidelines recommended 12 as the minimum number of lymph nodes harvested to ensure adequate sampling. This study aimed to identify factors that influence lymph node count (LNC) in left-sided colon and rectal cancer resection independent of pathologists and surgeons.


Data were prospectively collected from unfixed open (n=16) and laparoscopic (n=16) left-sided and rectal specimens. Morphometric data such as vascular pedicle length (VPL), surface area (SA), length of specimen (LoS) and volume of specimen (VoS) were collected from all specimens. White cell count (WCC) and Body mass index (BMI) were recorded for all patients.


11 total mesorectal excision (TME) and 5 left hemicolectomies (LH) were performed in the laparoscopic group compared to 10 TME and 6 LH in the open group. No significant difference was noted in the LNC between the cohorts. The significant correlations observed between LoS (p=0.01), VoS (p=0.007), SA (p=0.03), WCC (p=0.004), BMI (p=0.02), and LNC for open resections were not recapitulated in the laparoscopic cohort. On joint group analysis, no significant correlation was noted between LoS, VoS, SA, WCC, VPL and BMI, and LNC. Eleven (69%) open cases reported an adequate LNC, compared to 12 (75%) laparoscopic cases. Patients receiving neoadjuvant treatment in the open cohort (n=4) reported an inadequate LNC, however, the only patient receiving neoadjuvant treatment in the laparoscopic cohort reported an inadequate LNC. Moreover, LoS (p=0.001), VoS (p=0.004) and VPL (p=0.01) were significantly larger in the open group.


A significant correlation was highlighted between “operator-independent” factors and LNC in open specimens only, which could suggest a lack of standardisation of procedures across laparoscopic surgery. Further large, multi-centre studies are imperative to identify patient-specific LNC predictors to assess the adequacy of lymph node examination for each patient.