A high lymph node yield in colon cancer is associated with age, tumour stage, tumour sub-site and priority of surgery. Results from a prospective national cohort study.

Aim: To determine the relation between patient-related and histopathological factors, as well as the influence of national programs for diagnosing and treatment of colon cancer and a lymph node yield (LNY) ≥ 12.

Method: An analysis was carried out of the LNY in a nationwide Danish cohort treated by curative resection of stage I-III colon cancer in the period 2003-2011. The association between a LNY ≥ 12 and age, sex, body mass index, open vs. laparoscopic surgery, acute vs. elective surgery, pT stage, tumour sub-site and year of diagnosis was analysed.

Results: A total of 13,766 patients were eligible for the analysis. In total, 71.4 % of the patients had a LNY ≥ 12. In multivariate analysis, age, pT stage, tumour sub-site and priority of surgery were independently associated with the probability of a LNY ≥ 12. Odds ratios (ORs) were as follows: age <65 1, 65-75 0.685 (confidence interval (CI) 0.586-0.800), >75 0.517 (CI 0.439-0.609); T1 1, T2 2.750 (CI 2.168-3.487), T3 6.016 (CI 4.879-7.418), T4 6.317 (CI 4.950-8.063); right colon 1, left colon 0.568 (0.511-0.633); elective surgery 1, acute surgery 0.748 (CI 0.625-0.894). Moreover, year of diagnosis was associated with the probability of a LNY ≥ 12: OR 1.480 (CI 1.445-1.516) for each increasing year in the study period.

Conclusion: A LNY ≥ 12 is significantly associated with age, pT stage, tumour sub-site and priority of surgery. A significant increase in the LNY over the period of the study was observed, probably reflecting the effect of national programmes initiated by the Danish Colorectal Cancer Group.