Audit of Lymph Node Sampling in Colorectal Carcinoma Resections-implication for Prognosis and Management

Abstract

Aims: To review lymph node yield in colorectal carcinoma (CRC) resections and its associated factors in a Nigerian Teaching Hospital practice. Study design:  This was a retrospective cross-sectional study. Place and duration of study: Department of Pathology, University College Hospital Ibadan Nigeria and colectomies from January 2014 to December 2018 were reviewed. Methodology: Surgical Pathology reports of CRC resections at the University College Hospital Ibadan over 5 years (2014-2018) were reviewed. Colectomy lengths, tumour location (colon/rectum), tumour size, comment on presence of lymph node (yes/no), lymph node count, presence of attached mesentery (yes/no), histological subtype, tumour grade, presence of tumour-positive node and count, and pT stage were documented. Fisher’s Exact test was employed to test the effects of these variables on presence of lymph node and tumour-positive node at histology using SPSS 20. Significance level was set at P < .05. Results: Of 66 histology reports retrieved, 62 (93.9%) had comments on search for lymph nodes and attached mesentery was documented in 25 (37.9%). The median colectomy length and tumour size were 25cm (6cm-152cm) and 6.75cm (3-30cm) respectively. Lymph nodes were present in 52 (78.8%) specimens; 28 (53.8%) of these had tumour-positive lymph nodes. Adenocarcinoma NOS was the commonest histological subtype 53 (80.3%), mucinous carcinoma 12 (18.2%) and signet ring carcinoma 1 (1.5%). Eighteen, 9 and 1of adenocarcinoma NOS, mucinous carcinoma, and signet ring carcinoma respectively had tumour-positive lymph nodes. Finding of lymph node was significantly associated with comment on search for lymph node (p < .01) while finding tumour-positive nodes was associated with histological subtype, presence of mesentery, late tumour stage and lymph node count ≥ 12 (p < .05). Conclusion: If lymph nodes were present, more than likely there will be metastatic involvement. To increase Lymph node yield in CRC resections, submission of mesentery and search for lymph nodes is indicated. When nodes are absent, a mention is required for practice audit. It is imperative to include both clinical and grossing notes for lymph nodes to certify and guide precise staging of the cancer.