Sentinel Lymph Node Mapping in Colon Cancer: Current Status

Abstract

Background: The primary role of sentinel lymph node (SLN) mapping in colon cancer is to increase the accuracy of nodal staging by identifying those lymph nodes with the greatest potential for harbouring metastatic disease. Ultrastaging techniques aim to identify the otherwise undetected metastases. Until now, no consensus exists as to the most optimal procedure in patients with colon cancer.Methods: A systematic literature search on the value of different SLN mapping techniques in patients with colon cancer was performed using the electronic search engine PubMed. Prospective studies published before 1 December 2005 were included and further articles were selected by cross-referencing. The results of different techniques using either blue dye or radiocolloid, were investigated.Results: The literature search yielded 17 relevant articles. SLN mapping using blue dye was described in 15 studies. Two studies reported the results of SLN mapping using a combination of blue dye and radiocolloid. The reported results on identification rate varied between 71 and 100%. Accuracy rates were between 78 and 100%, sensitivity rates between 25 and 100% and true upstaging rates between 0 and 26%. The results were not affected by the addition of radiocolloid to blue dye.Conclusions: Sentinel lymph node mapping in patients with colon cancer remains an experimental procedure with varying results. Further evaluation may lead to a standardized technique that offers the potential for significant upstaging of stage II patients. This may have important implications as to tailor adjuvant chemotherapeutic regimens in these patients.

Clinically important aspects of lymph node assessment in colon cancer

“…Importantly, the SLN identification process for colon cancer can be done before the tumour is resected (in vivo) or afterwards (ex vivo) [50]. In addition, lymphatic mapping for colon cancer is typically performed using blue dye rather than the combination of radiocolloid/blue dye that is recommended for breast cancer and melanoma SLN mapping [51,52]. A recent systematic review on the current status of sentinel node mapping in colon cancer which reported that the sentinel node identification rate, using blue dye alone, was between 71% and 100%, and the false negative rate ranged between 0% and 54% [51].…”

“…In addition, lymphatic mapping for colon cancer is typically performed using blue dye rather than the combination of radiocolloid/blue dye that is recommended for breast cancer and melanoma SLN mapping [51,52]. A recent systematic review on the current status of sentinel node mapping in colon cancer which reported that the sentinel node identification rate, using blue dye alone, was between 71% and 100%, and the false negative rate ranged between 0% and 54% [51]. In the two studies (n ¼ 25, 57) that used both radiocolloid and blue dye, the identification rate was 88% and 98% and the false negative rate was 45% and 17% [51].…”

“…A recent systematic review on the current status of sentinel node mapping in colon cancer which reported that the sentinel node identification rate, using blue dye alone, was between 71% and 100%, and the false negative rate ranged between 0% and 54% [51]. In the two studies (n ¼ 25, 57) that used both radiocolloid and blue dye, the identification rate was 88% and 98% and the false negative rate was 45% and 17% [51]. A recent study that used blue dye only to identify the sentinel node found that a high false negative rate was associated with a higher body mass index (>24 kg/m 2 ) [53].…”

“…In addition, experience of the unit (<22 cases vs. >22 cases) is also associated with sentinel node identification rate [53], mirroring the melanoma [54] and breast cancer experience [55]. Finally, aberrant lymphatic drainage or drainage to a lymph node in an area outside of the standard lymphadenectomy was most commonly to nodes located deep at the base of the mesentery and occurred 0-36% of the time [51].…”

Pesquisa de linfonodo-sentinela em pacientes com adenocarcinoma de cólon

“…Em recentes revisões de trabalhos relevantes, levando-se em consideração diferentes técnicas, a identificação de linfonodo-sentinela variou de 71 a 100% 18,19 .…”