More recommendations for lymph node adequacy in CRC

The Dutch National Working Group on Gastrointestinal Cancers has recently released colorectal cancer guidelines which includes a recommendation of a minimum of 10 lymph nodes to establish a negative lymph node status.  At the same time, the group states that "determining the lymph node status of a patient requires evaluation as many lymph nodes as possible using conventional techniques." (emphasis mine

The discussion of this recommendation states that "no definitive criteria were found in the literature regarding the minimum number of examined lymph nodes.  There is no evidence to support 12 lymph nodes, as recommended by TNM." (emphasis mine)

Furthermore, they specifically do not recommend using immunohistochemistry to detect metastases or pre-treatment of mesenteric fat with GEWF-type solutions.  While using the former to detect micrometastases is not common practice, as least in the U.S., the latter is not only fairly common, if not routine in many places (mine included!).  Also, the recent literature also supports the use of these solutions to increase lymph node retrieval, although the utility of the raw node count has been questioned with the data regarding the percentage or proportion of positive:negative nodes (whole other discussion!).

Comments

[Mark Pool]

My own personal experience is similar to Alex's. I too have had cases in which I've found one out of 20+ or 30+ nodes. And microscopically positive nodes that were grossly unremarkable but small (2-3 mm). One wonders about the significance of involvement of small nodes versus large macro-positive nodes--especially when the ratio is 1 out of 20+ nodes. I think that this is where the value of percent positive or ratio quartiles is of interest. But this still doesn't address the issue of whether a certain critical number of nodes examined is necessary to deem a patient as N0.

[Alex]

Anecdote alert. I once found one positive node among 30 retrieved from the mesocolon. Not sure whether it was the first, twelfth or thirtieth node, but I think the object lesson is to submit as many nodes as you can find.
I have found that positive nodes are not invariably large and hard.

[EM]

I find that discussion on the optiminal/minimal number of LNs in colectomies difficult to understand.

In my experience, nodes with metastatic CRC are all large and hard, hence easy to find. So where is the problem?