[R1 resection for gastric carcinoma]

Area of Science:

• Gastroenterology
• Surgical Oncology
• Pathology

Background:

• R1 resection, defined as microscopic tumor at the surgical margin, negatively impacts long-term survival in resected gastric carcinoma.
• The prognostic significance of R1 resection varies with tumor stage and lymph node involvement.
• While R0 resection (no tumor at the margin) is ideal, R1 situations present challenges in gastric cancer surgery.

Purpose of the Study:

• To review the literature on R1 resection in gastric cancer.
• To analyze factors influencing R1 rates and their impact on patient survival.
• To discuss current strategies for achieving R0 resection and the role of re-excision.

Main Methods:

• Literature review of studies reporting on R1 resection in gastric cancer.
• Analysis of factors associated with increased R1 rates, including tumor size, stage, and histology.
• Evaluation of the impact of R1 status on survival and the effectiveness of re-excision.

Main Results:

• R1 resection significantly worsens prognosis, especially in early T stages with limited lymph node metastasis.
• R1 resection rates are around 5% for gastric cancer and over 10% for esophagogastric junction adenocarcinomas.
• Tumor size (>5 cm), advanced T/N stages, poor differentiation, and specific histologies increase R1 risk.
• Intraoperative frozen section is standard for R0 achievement; re-excision is recommended if R1 is found postoperatively, though rarely performed.

Conclusions:

• Achieving R0 resection is critical for improving gastric cancer patient survival.
• While re-excision after R1 detection can improve outcomes, it is infrequently utilized.
• Further evidence is needed regarding the role of adjuvant therapies in R1 resection cases.