Clinicopathologic study of early-stage mucinous gastric carcinoma

Mucinous gastric carcinoma (MGC) is rare, and whether MGC behaves more aggressively than nonmucinous gastric carcinoma (NGC) is controversial. To the authors' knowledge, there is no study of early-stage MGC, and the pathology and prognosis of patients who have early MGC is unknown. The aim of this study was to clarify the clinicopathologic characteristics of early MGC.

Pathologic and prognostic data of 30 patients who had early MGC were compared retrospectively against data of 165 patients who had early NGC and 58 patients who had advanced MGC. We defined MGC as a tumor in which more than half of the tumor area contained extracellular mucin pools. We defined early gastric carcinoma as a tumor restricted to the mucosa or to the mucosa and submucosa (T1, International Union Against Cancer [UICC], 1997) regardless of lymph node metastasis.

Early MGC tumors, compared with early NGC tumors, were characterized by macroscopic elevation (57% vs. 23%, P < 0.01) and invasion to the submucosa (83% vs. 44%, P < 0.01). Tumor size, frequency of lymph node metastasis, and patient outcome did not differ between the two types, and no patient with early MGC died of recurrence during a median follow-up period of 67 months. When early MGC was compared with advanced MGC, tumor size (2.9 cm vs. 9.4 cm, P < 0.01), frequency of lymph node metastasis (10% vs. 88%,P < 0.01), total gastrectomy (0% vs. 52%, P < 0.01), noncurative surgery (0% vs. 38%, P < 0.01), and recurrent death (0% vs. 57%, P < 0.01) differed significantly.

Our results indicated that although the macroscopic features of early MGC differed from those of early NGC, patient prognosis and the frequency of lymph node metastasis did not differ. Neither did mucinous histology seem to influence outcome adversely after gastrectomy.