Tattooing improves the detection of small lymph nodes and increases the number of retrieved lymph nodes in patients with rectal cancer who receive preoperative chemoradiotherapy: A randomized controlled clinical trial

Background: In rectal cancer who received chemoradiotherapy, the number of Lymph nodes (LNs) required remains unclear. We conducted a randomized controlled trial to determine whether preoperative tattooing increases the number of LNs and enhances the detection rate of metastatic LNs. Methods: Eighty patients with rectal cancer who received chemoradiotherapy were randomly assigned to receive no tattooing (C group) or to receive tattooing (T group). Results: The number of LNs was significantly higher in the T group (13.3 +/- 7.4, mean +/- SD) than in the C group (8.8 +/- 5.9, p < 0.001), however, the number of positive LNs did not differ (0.5 +/- 1.3 vs. 0.5 +/- 1.1, p = 0.882). The long-axis diameter of LNs was significantly smaller in the T group than in the C group (3.4 +/- 1.8 vs. 3.9 +/- 2.3 mm, p < 0.001), however, the long-axis diameter of positive LNs did not differ. Conclusions: Tattooing increased the number of retrieved LNs by 51%, however, there was no increase in the number of positive LNs. (C) 2017 The Authors. Published by Elsevier Inc.