Purpose: To investigate the pattern of lymphatic drainage in gastric cancer patients to predict sentinel node placement according to tumor location.
Methods: A total of 462 pT1 or T2 gastric adenocarcinoma patients with metastasis to 1-3 lymph nodes (LNs) who had undergone lymphadenectomy greater than D1+β were included in the study. The distribution of metastatic LNs was evaluated according to tumor longitudinal and circumferential location. The incidence rate of atypical metastasis (skip or transversal metastasis) and related clinicopathologic factors were analyzed.
Results: The rates of skip and transversal metastasis were 15.8 % (73 of 462) and 10.3 % (23 of 224), respectively. Atypical metastasis was observed regardless of tumor location. Tumors that showed the most frequent atypical metastasis were located in the lower third and lesser curvature (LC) of the stomach (29.0 % for skip metastasis and 18.0 % for transversal metastasis). In uni- and multivariate analyses, an LC tumor was a risk factor for skip metastasis, and tumor located circumferentially in the LC or longitudinally in the lower third of the stomach was an independent risk factor for transversal metastasis. There was no correlation between tumor aggressiveness and atypical metastasis.
Conclusions: Tumors at any location had a chance of atypical metastasis; however, those located longitudinally in the lower or circumferentially at the LC had a significantly higher chance of atypical metastasis compared to other locations. When sentinel node navigation surgery is applied, special care should be taken with tumors at these locations to prevent false-negative results.