It can be cured!
Early gastric cancer is defined as gastric cancer whose depth of infiltration is limited only to the mucosa or submucosa, regardless of the presence of lymph node metastasis.
The outcome of early gastric cancer is better, with a 5-year survival rate of more than 90% and a 10-year survival rate of 80% or more. The degree of differentiation, depth of tumor infiltration, and lymph node metastasis in early gastric cancer affects outcome. Patients with poor differentiation, deep infiltration, and lymph node metastasis generally have poorer outcomes, with indolent cell carcinoma being a more specific type. Although indolent cell carcinoma is classified as undifferentiated on histologic typing, it has a better outcome than other undifferentiated types, is similar to the differentiated type, and has a lower probability of lymph node metastasis.
Overall, it appears that early gastric cancer is usually curable, with a recurrence rate of only 2.7% after radical resection (R0 surgery). (Pengliang Wang, Department of Gastrointestinal Oncology, The First Hospital of China Medical University, contributed to the answer)