1 Department of Clinical Medicine, Department of Clinical Medicine, Faculty of Health and Medical Sciences, Københavns Universitet2 unknown3 Department of Clinical Medicine, Department of Clinical Medicine, Faculty of Health and Medical Sciences, Københavns Universitet
Results from a national cohort study
PURPOSE: The purpose of the study was to examine if a minimum of 12 lymph nodes (LNs) is still valid in rectal cancer after neo-adjuvant treatment. METHODS: An analysis was carried out in a nationwide Danish cohort of 6793 patients, treated by curative resection of stage I-III rectal cancer during the period 2003-2011. The cohort was divided into two groups according to whether neo-adjuvant treatment had been given. The groups were analysed separately and were further analysed according to four lymph node yield (LNY) groups 0-5, 6-11, 12-17 and ≥18. RESULTS: Two thousand one hundred twenty-three patients (31.0 %) received neo-adjuvant treatment. A median LNY of 10 and 15 (p < 0.0001) and rates of node-positive (N-positive) disease of 31.6 and 36.7 % (p < 0.001) were observed with and without (+/-) neo-adjuvant treatment, respectively. The rate of N-positive disease according to tumour stage ranged from 4.8 %/11.4 % (ypT0/pT1) to 42.1 %/64.1 % (ypT4/pT4). The rate of N-positive disease according to LNY ranged from 19.5 %/16.8 % (0-5 LNs) to 42.6 %/37.9 % (≥18 LNs) (-/+neo-adjuvant treatment). In a logistic regression analysis, a significant association was found between N-positive disease and pT/ypT stage as well as between N-positive disease and LNY. CONCLUSIONS: A significantly smaller ratio of N-positive disease was observed in the group of patients who had received neo-adjuvant treatment. The ratio of N-positive disease increased significantly with more advanced tumour stage and increasing LNY irrespective of neo-adjuvant treatment. A minimum of 12 LNs is needed to ensure N-negative disease, irrespective of neo-adjuvant treatment.
International Journal of Colorectal Disease, 2015, Vol 30, Issue 3, p. 347-351