Postoperative intra-arterial methylene blue injection of colorectal cancer specimens increases the number of lymph nodes recovered.

AIMS: To determine the possible advantage of intra-arterial injection of methylene blue with a view to improving lymph node recovery in postoperative examination of colorectal cancer specimens. METHODS AND
RESULTS: Thirty-two colorectal cancer specimens were assigned randomly to either dissection with intra-arterial methylene blue injection or to routine dissection (without methylene blue injection). Immediately postoperatively, the specimens in the staining group were injected intra-arterially with methylene blue dye. The two procedures were compared with respect to the number of lymph nodes recovered. The number of recovered lymph nodes was significantly higher in the intra-arterial methylene blue injection group than in the group investigated with routine procedures (P<0.0001).
CONCLUSION: The intra-arterial methylene blue injection method is fairly easy to use postoperatively and increases significantly the number of lymph nodes recovered in colorectal cancer specimens.