Background and aim: Endoscopic mucosal resection (EMR) is currently not accepted as an alternative treatment
to surgery in early gastric cancer (EGC) of the undifferentiated histologic type.
The present retrospective analysis examined the correlation of various histologic
factors with the presence of lymph node metastasis (LNM).
Patients and methods: A retrospective analysis on 234 patients with poorly differentiated EGC who underwent
radical gastrectomy with D2 lymph node dissection was undertaken. Several clinicopathologic
factors were investigated to identify predictive factors for LNM: age, sex, type of
operation, tumor location, tumor size, gross type, ulceration, lymphatic invasion,
and depth of invasion.
Results: Of the 234 lesions with poorly differentiated EGC, half (n = 116) already showed
submucosal invasion in the resection specimen; 25.9 % of those (30/116) were limited
to the upper third (SM1). Of the lesions confined to the mucosa, LNM was found in
3.4 % (4/118). With minor submucosal infiltration (SM1), the LNM rate was lower (0/30)
in our patient population. Only with SM2/3 infiltration did the LNM rate sharply rise
to around 30 %. The cut-off for submucosal infiltration depth was 500 μm (0/32 LNM),
above which LNM rates were substantial (31.2 %; 24/77). There was limited correlation
between the SM1-3 classification and actual measurement of submucosal infiltration
depth. In a multivariate analysis, tumor size (P = 0.033), depth of invasion (P = 0.004), and lymphatic invasion (P < 0.001) were associated with LNM.
Conclusion: Poorly differentiated EGC confined to the mucosa or with minimal submucosal infiltration
(≤ 500 μm) could be considered for curative EMR due to the low risk of LNM. Given
the limited case number of subgroups, these findings should be confirmed by more data
from other centers, which should also focus on local recurrence after EMR in poorly
differentiated EGC.
References
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