Evaluation of lymph node metastasis in patients with gastric cancer: a comparison of the directionality of lymph node metastasis and the total number of metastatic lymph nodes.

Purpose: The clinical impact of the directionality of lymph node (LN) metastasis was assessed in comparison with the staging by the Japanese Classification of Gastric Carcinoma (JCGC), a numerical LN staging system.

Methods: Two hundred forty-one gastric cancer patients who were diagnosed pathologically to have LN metastasis, and 54 patients who underwent preoperative multidetector-row computed tomography (MDCT) with an image thickness of 1 mm were classified into three groups (unidirectional [Uni-], bidirectional [Bi-], and tridirectional [Tri-] groups) depending on the directionality of their LN metastasis.

Results: The prognosis of the Uni-group was better than that of the Bi- or the Tri-group when assessed on the basis of the pathological findings of metastatic LN and also the preoperative MDCT findings. The exact preoperative evaluation was 70.2 % for the directionality system and 61.7 % for the JCGC system, respectively. The stages were less frequently underestimated by the directionality system than the JCGC system (P < 0.02, 19.1 vs. 34.0 %), and the staging could be more precisely performed by both systems in combination.

Conclusions: More precise preoperative evaluation of disease stage could be obtained by the directionality system and the JCGC system in combination.