Practical value of the complex analysis of sentinel lymph nodes in colorectal carcinomas.

Background: Despite modern factors, which seem to predict outcome, lymph node (LN) status remain the main prognostic factor, which also shows the need for complex oncotherapy in colorectal carcinomas (CRC). Sentinel lymph nodes (SLNs) mapping is a very controversial method, which can increase the number of identified LN.

Materials And Methods: In 28 patients who underwent surgical intervention between December 2009 and December 2010, we performed in vivo SLNs mapping followed by ex vivo examination at 1, 10, and 48 hours. All blue nodes were separately included. In cases without LN metastases (pN0) five multilevel sections and immunohistochemical stain with cytokeratin 20 were performed in SLNs.

Results: Two cases were excluded because they were in pT4 stage. In one case the diameter of lymph nodes was about 10 mm and we obtained a false negative result (negative SLNs with positivity in the non-SLNs). From the other 25 cases, 13 do not presented LN metastases or micrometastases, nine had metastases only in the SLNs and the other three in both SLNs and non-SLNs. Mean identified number of LNs was 15. The blue dye intensity increased after formalin fixation and some nodes with metastases were blue stained only after 10 hours.

Conclusions: SLNs mapping is a simple and inexpensive technique, which can improve the management of CRC. All in vivo and ex vivo blue LNs should be considered SLNs. Ultrastaging of SLNs is an expensive method, with uncertain results. High diameter of LNs seems to be an exclusion criterion for SLNs mapping.