Methylene blue-assisted lymph node dissection in combination with ex vivo sentinel lymph node mapping in gastric cancer

Aims:  Lymph node (LN) stage is still the strongest prognostic marker in potentially curable gastric cancer. Accuracy of histopathological lymph node assessment depends on the number of investigated LNs and detection rate of metastases and micrometastases. The aim was to perform a feasibility study employing intra-arterial methylene blue injection – a novel method to improve LN harvest – and ex vivo sentinel LN mapping.
Methods and results:  A total of 33 cases were enrolled, including 14 retrospective cases that served as a control group. The methylene group showed a highly significant improved mean LN harvest compared with unstained cases, with 38 ± 14 versus 21 ± 10 LNs ( P  < 0.001), respectively. The detection rate of ex vivo sentinel mapping was 88%. No skip metastases occurred.
Conclusion:  Both techniques have the potential to improve the accuracy of histopathological LN staging and can be combined successfully.