Published online Nov 21, 2015. doi: 10.3748/wjg.v21.i43.12218
Peer-review started: May 15, 2015
First decision: July 14, 2015
Revised: September 1, 2015
Accepted: October 23, 2015
Article in press: October 26, 2015
Published online: November 21, 2015
Lymph node staging is of crucial importance for the therapy stratification and prognosis estimation in colon cancer. Beside the detection of metastases, the number of harvested lymph nodes itself has prognostic relevance in stage II/III cancers. A stage migration effect caused by missed lymph node metastases has been postulated as most likely explanation for that. In order to avoid false negative node staging reporting of at least 12 lymph nodes is recommended. However, this threshold is met only in a minority of cases in daily practice. Due to quality initiatives the situation has improved in the past. This, however, had no influence on staging in several studies. While the numbers of evaluated lymph nodes increased continuously during the last decades the rate of node positive cases remained relatively constant. This fact together with other indications raised doubts that understaging is indeed the correct explanation for the prognostic impact of lymph node harvest. Several authors assume that immune response could play a major role in this context influencing both the lymph node detectability and the tumor’s behavior. Further studies addressing this issue are need. Based on the findings the recommendations concerning minimal lymph node numbers and adjuvant chemotherapy should be reconsidered.
Core tip: The number of evaluated lymph nodes is prognostic in stage II and III colon cancers. Understaging due to inadequate lymph node harvest causing a stage migration effect is a widely accepted explanation for this. However, there is growing evidence that understaging plays only a minor role in this context. It seems much more likely that immune response has influence on the lymph nodes’ detectability and is associated with outcome in colon cancer.