What is the prognosis of gastric adenocarcinoma?

Prognosis of Gastric Adenocarcinoma

Gastric adenocarcinoma generally carries a poor prognosis because it is often diagnosed at an advanced stage, with an overall 5-year survival rate of approximately 26% after resection. 1

Prognostic Factors

Stage at Diagnosis

The stage of disease at diagnosis is the most significant determinant of prognosis:

• Early Gastric Cancer (EGC):

  • Limited to mucosa or submucosa (T1)
  • 5-year survival >90% when appropriately treated 1
  • Excellent prognosis when meeting criteria for endoscopic resection

• Locally Advanced Disease:

  • Stage II-III: 5-year survival rates range from 20-50% depending on exact stage
  • Perioperative chemotherapy can improve 5-year survival from 23% to 36.3% 1

• Metastatic Disease:

  • Stage IV: Median survival approximately 9-12 months 2
  • With modern chemotherapy regimens, median overall survival is about 9.2 months for patients receiving docetaxel-based regimens 3

Resection Status

Complete surgical resection (R0) significantly improves prognosis:

• 5-year survival after R0 resection: 33% 4
• Incomplete resection (R1/R2): Significantly worse outcomes

Histological Factors

• Lauren Classification:
  • Intestinal type: Better prognosis
  • Diffuse type: Worse prognosis, particularly when glucose-avid on PET imaging 5
  • Diffuse type with low SUV on FDG-PET: Median OS of 98.0 months
  • Diffuse type with high SUV on FDG-PET: Median OS of only 36.0 months 5

Patient-Related Factors

• Age: Younger patients (<45 years) may have better long-term survival after curative resection despite often presenting with more aggressive disease 6
• Nutritional Status: BMI below 20 is an independent poor prognostic factor 7
• Performance Status: Better performance status correlates with improved outcomes
• Serum Albumin Levels: Low levels associated with worse prognosis 7

Treatment Impact on Prognosis

Surgical Intervention

• Surgery remains the only potentially curative treatment for localized disease
• No surgical treatment or only palliative surgery (vs. radical surgery) are statistically significant poor prognostic factors 7
• Extent of lymphadenectomy remains debated, but adequate lymph node retrieval (minimum of 14, optimally 25) is recommended 1

Multimodal Therapy

• Perioperative Chemotherapy:

  • Improves 5-year survival from 23% to 36.3% in locally advanced disease 1
  • ECF (epirubicin, cisplatin, 5-FU) or modifications are commonly used regimens

• Adjuvant Chemoradiotherapy:

  • Can improve 5-year overall survival by approximately 15% in certain populations 1

• Targeted Therapies:

  • HER2 status, microsatellite instability (MSI) status, and PD-L1 expression significantly impact treatment options and outcomes 1
  • Trastuzumab, nivolumab, and pembrolizumab have shown encouraging results in clinical trials for advanced disease 1

Common Pitfalls in Prognostication

1. Failure to adequately stage disease: Complete staging with endoscopy, CT, and potentially EUS and diagnostic laparoscopy is essential for accurate prognostication

2. Not accounting for molecular subtypes: HER2 status, MSI status, and PD-L1 expression significantly affect treatment options and outcomes

3. Overlooking the importance of complete (R0) resection: This is a critical determinant of long-term survival

4. Not considering patient-specific factors: Nutritional status, performance status, and comorbidities significantly impact prognosis

5. Geographic variations in outcomes: Survival rates for gastric cancer are generally higher in Eastern compared to Western populations, possibly due to earlier detection through screening programs and differences in tumor biology 4

In conclusion, while gastric adenocarcinoma generally has a poor prognosis when diagnosed at advanced stages, early detection and appropriate multimodal therapy can significantly improve outcomes. The integration of molecular profiling and targeted therapies offers new hope for improving survival in this challenging disease.