Definition of Locally Advanced Gastric Carcinoma
Locally advanced gastric carcinoma is defined as a tumor which has invaded the muscularis propria or deeper layer of the gastric wall (T2 or higher), which may include regional lymph node involvement but without distant metastases. 1
Pathological Classification
Locally advanced gastric carcinomas are macroscopically sub-classified according to the Borrmann classification into four subtypes 1:
- Type I: Polypoid/fungating tumor without ulceration
- Type II: Ulcerated tumor with elevated borders and sharp margins
- Type III: Ulcerated tumor with diffuse infiltration at the base
- Type IV: Diffusely infiltrative tumor with thickening of the wall (linitis plastica)
This classification differs from early gastric cancer, which is defined as cancer confined to the mucosa and submucosa, regardless of lymph node involvement 1
Staging Considerations
The TNM staging system from AJCC/UICC is the standard for staging locally advanced gastric cancer 1
T-staging for locally advanced disease includes:
- T2: Tumor invades muscularis propria
- T3: Tumor invades subserosal connective tissue
- T4a: Tumor penetrates serosa
- T4b: Tumor invades adjacent structures 1
Regional lymph node involvement is classified as N1-N3 based on the number of positive lymph nodes 1
Clinical Implications
- Locally advanced gastric cancer typically requires more aggressive multimodal treatment approaches compared to early gastric cancer 2, 3
- Accurate clinical staging is essential using combined examination modalities to determine resectability 2
- Perioperative chemotherapy with FLOT regimen is the current standard of care for resectable locally advanced gastric cancer 2, 3
- For unresectable locally advanced disease, concurrent chemoradiotherapy is the preferred approach for patients with good performance status 2
Diagnostic Evaluation
- Endoscopic examination with multiple biopsies (5-8) is the gold standard for diagnosis 1
- Endoscopic ultrasound (EUS) is helpful to identify the depth of wall invasion 1
- CT scan of the abdomen is essential for evaluating local extension and regional lymph node involvement 1, 4
- Laparoscopic exploration with cytological examination of peritoneal washings is recommended to detect occult metastases 2, 3
Common Pitfalls in Assessment
- Inadequate staging may lead to inappropriate treatment selection; comprehensive staging including laparoscopic exploration is crucial 2, 3
- Inadequate lymph node evaluation (fewer than 14 nodes) may lead to understaging and suboptimal treatment 3
- Regular re-evaluation of tumor response during treatment is necessary to identify opportunities for surgical intervention 2
Prognostic Factors
- Surgical margin status significantly impacts survival outcomes 5
- Signet-ring cell histology is associated with worse prognosis 5
- The stage of disease directly correlates with survival rates, with 5-year overall survival rates of 75% for stage IB, 45% for stage II, and 8.3% for stage III 5
Understanding the definition and classification of locally advanced gastric carcinoma is critical for appropriate treatment planning and improving patient outcomes through a multidisciplinary approach.