Reconsidering the terminology of "early" and "advanced" gastric cancer: toward a harmonized global lexicon.

Historical background
The concept of early gastric cancer (EGC) was first introduced in Japan in the 1960s by gastroenterologists, surgeons, and pathologists, in parallel with major advances in endoscopic diagnosis and surgical pathology [1]. EGC was defined as carcinoma confined to the mucosa or submucosa, irrespective of lymph node metastasis, and this definition has since become established both in Japan and internationally [2]. The widespread adoption of EGC reflects its clinical utility in identifying tumors with an excellent prognosis when treated appropriately.
While the definition of EGC has been clearly articulated and consistently applied, the corresponding terminology for more deeply invasive gastric cancer has not been formally standardized, particularly in English-language usage.

Semantic discrepancy and clinical confusion
In Japan, gastric cancers that do not meet the definition of EGC are referred to in clinical practice as “advanced gastric cancer,” primarily based on depth of invasion (T2 or deeper) [3]. However, in Western oncology, the term advanced cancer is commonly reserved for disease that is unresectable and/or metastatic, typically corresponding to stage IV [4].
Conversely, the term early-stage cancer in Western usage frequently encompasses a broader range of disease, including resectable stage II and even stage III tumors [5]. As a result, a gastric cancer described as “advanced” in the Japanese context may be interpreted by Western clinicians as terminal or palliative disease, despite being potentially curable by surgery even without chemotherapy. This discrepancy has practical implications for international collaboration, trial design, and interpretation of outcomes.

A proposal for harmonization
To address this inconsistency, we propose a three-tier terminology for gastric cancer (Table 1). The term locally advanced cancer is already widely used across many solid tumors to describe stage II–III disease that is locally extensive but potentially amenable to curative-intent treatment, often in combination with multimodal therapy.

Tumor-specific considerations of “locally advanced”
It is important to acknowledge that the meaning of locally advanced cancer is not uniform across all malignancies. In pancreatic cancer, for example, the term frequently refers to tumors with extensive local vascular involvement that precludes surgical resection despite the absence of distant metastasis [6]. This usage reflects tumor-specific anatomical and biological constraints rather than a general staging principle.
In gastric cancer, however, locally advanced has long been used in Western and global clinical trials and guidelines, albeit without a universally accepted formal definition, to describe resectable disease requiring perioperative or neoadjuvant therapy [7–9]. Making this implicit usage explicit by defining locally advanced gastric cancer as resectable stage II–III disease may help reduce semantic misunderstanding between regions and facilitate clearer international communication.

Conclusion
While the concept of early gastric cancer has achieved worldwide acceptance, the terminology used to describe more advanced disease has diverged across regions. The unqualified use of “advanced gastric cancer” risks semantic misunderstanding when applied to resectable tumors. We propose adopting a three-tier classification—early, locally advanced, and advanced gastric cancer—to harmonize Japanese pathological concepts with international clinical staging and treatment paradigms. Such a shared lexicon will facilitate clearer communication and stronger global collaboration in gastric cancer care.