Clinicopathological Features and Prognosis of Mixed-Type T1a Gastric Cancer Based on Lauren's Classification.

Background: Recent studies have reported that mixed-type (MT) gastric cancer, as per Lauren's classification, exhibits aggressive behavior. However, the behavior of early gastric cancer is unclear. In this study, we addressed the influence of mucosa-confined MT gastric cancer, according to Lauren's classification, on lymph node metastasis (LNM) and long-term outcomes.

Methods: Among patients who underwent gastrectomy for gastric cancer from January 2000 to December 2012, 3170 had mucosa-confined gastric cancer. According to Lauren's classification, 1449 (45.7 %), 1528 (48.2 %), and 193 (6.1 %) patients had intestinal type (IT), diffuse type (DT), and MT cancer, respectively. Moreover, patients with MT cancer were histologically subdivided into IT-predominant MT (3.0 %) and DT-predominant MT (2.5 %) groups. We analyzed and compared the clinicopathological characteristics, incidence of LNM, overall survival, and recurrence-free survival between these groups.

Results: Clinicopathological characteristics showed that mucosa-confined MT gastric cancer had larger size, deeper invasion, and more frequent lymphovascular invasion compared with IT or DT cancers. The LNM of MT lesions (4.7 %) was comparable with that of DT lesions (4.8 %), and multivariate logistic regression analysis indicated that Lauren's classification was a significant predictor for LNM (P < 0.001). However, the overall survival and recurrence-free survival of patients with MT lesions did not differ significantly (P = 0.506 and 0.359, respectively).

Conclusions: Thus, among patients with mucosa-confined gastric cancer, those with MT cancer as per Lauren's classification have aggressive clinical features and a risk of LNM. Hence, surgical treatment may be the preferred option in these patients.