Identifying predictors of lymph node metastasis after endoscopic resection in patients with minute submucosal cancer of the stomach.

Background: The use of endoscopic submucosal dissection (ESD) for the treatment of minute submucosal (SM) invasive cancer that fulfills the current expanded criteria remains controversial. This study investigated the clinicopathological parameters of patients with sm1 gastric cancers to predict lymph node metastasis (LNM) and evaluate the feasibility of ESD as a curative treatment.
Methods: Data from 278 patients who underwent surgical resection of sm1 gastric cancer between 2006 and 2010 were retrospectively collected, and their clinicopathological parameters were analyzed to identify predictive factors of LNM.
Results: Of 278 patients, 28 patients (10.1 %) had LNM. Multivariate analysis identified multiple lesions (p = 0.018), lymphovascular invasion (LVI) (p < 0.001), SM invasion depth >500 µm (p = 0.007), undifferentiated histology (p = 0.012), and ulceration (p = 0.024) as factors significantly associated with LNM in patients with sm1 gastric cancer. Additionally, SM invasion width/superficial tumor size ratio >0.04 (p = 0.036) demonstrated a significant association with LNM in patients with sm1 gastric cancer falling within the current expanded criteria for ESD. LNM was not identified among 35 patients who met the absence of ulceration, SM invasion depth ≤ 500 µm, and SM invasion width/superficial tumor size ratio ≤ 0.04 besides the current expanded indications.
Conclusions: Endoscopic resection can be performed on patients with minute SM invasive, differentiated cancers of ≤ 3 cm without LNM on pretreatment examination. In addition, if histological assessment shows the absence of LVI and ulceration, SM invasion depth ≤ 500 µm, and SM invasion width/superficial tumor size ratio ≤ 0.04, the patient can be carefully observed without additional treatment.