Early gastric cancer: diagnosis, staging, and clinical impact. Evaluation of 530 patients. New elements for an updated definition and classification.

Background: The prevention and early diagnosis of gastric cancer permit clinicians to discover the tumor in the initial phase, during which time it can be completely eradicated, endoscopically or surgically. Since Murakami gave the definition of early gastric cancer (EGC) in 1971, many authors have identified various subtypes of EGC with different morphological characteristics and clinical behaviour.

Methods: We evaluated retrospectively 530 patients: the median follow-up time was 10.4 months (range 0.3-29.2). All tumors were classified according to the macroscopic and microscopic criteria proposed by the Japanese Society of Gastroenterology and Endoscopy and Lauren, respectively. The infiltrative growth pattern was evaluated according to Kodama's classification. Only tumor-related death was considered as an endpoint of interest for the survival analysis.

Results: The overall survival rates of our patients were 94 % (95 % CI, 92-96) and 90 % (95 % CI, 87-93) at 5 and 10 years, respectively. Only 44 patients (8.3 %) died of the disease. Kodama's type (p < 0.0001), lymph node status, both for number and pathological stage according to the 7th Edition of TNM (p < 0.0001), and depth of infiltration (p = 0.0006) were significant prognostic factors in univariate analysis. The multivariate analysis identified Kodama's PENA type (HR, 3.91; 95 % CI, 2.08-7.33; p < 0.0001) and lymph node status for more than three positive nodes versus negative nodes (HR, 12.78; 95 % CI, 5.37-30.43; p < 0.0001) as the only independent prognostic factors in our series.

Conclusion: Lymph node status, especially when more than three lymph nodes are involved, is the most important prognostic factor in EGC. However, it is also important to evaluate the infiltrative growth pattern of the cancers in their early phase according to Kodama's classification, considering PEN A type lesions to be more aggressive than the other EGC types. Then, we propose new elements for an updated definition and classification of EGC, with an important clinical impact on the treatment of patients.