Enhanced lymph node retrieval from colorectal cancer resections using a simple lymphatic staining method.

BACKGROUND/AIMS: This study evaluated the effect of lymphatic staining on the number of lymph nodes (LNs) examined and staging in patients with colorectal cancer.

METHODOLOGY: Sixty-two consecutive specimens from patients with colorectal cancer resected between February 2009 and April 2010 were randomized to the stained group or the control unstained. Differences in the retrieval, number and size of nodes, and time for retrieval were measured.

RESULTS: LN harvest differed significantly with 30±12 and 13±5 (p<0.01) nodes in the stained and the control groups, respectively. Insufficient LN harvest (less than 12 nodes) occurred in 14 cases of the control group and only in 1 case of the stained group (p<0.01). Metastases were confirmed in 57 LNs occurring in 17 cases of the stained group and in 39 nodes occurring in 15 cases of the control group. The mean time for LN retrieval in the stained and control groups were comparable, 27.6±6.9min and 24.7±6.0min (p>0.05), respectively, yet there was a significant difference in the number of LNs (<2mm) (294 vs. 59, respectively, p<0.01) as well as in the number of LNs 2-5mm in size (474 vs. 220, respectively, p<0.01).

CONCLUSIONS: By lymphatic staining method, more and smaller LNs could be detected, which significantly improved the LN harvest of resected colorectal specimens and reduced cases of insufficient LN harvest.