Clinical importance and surgical decision-making regarding proximal resection margin for gastric cancer.

Because of the intramural spread of gastric cancer, a sufficient length of a resection margin has to be attained to ensure complete excision of the tumor. There has been debate on an adequate length of proximal resection margin (PRM) and its related issues. Thus, the objective of this article is to review several studies on PRM and to summarize the current evidence on the subject. Although there is some discrepancy in the recommended values for PRM between authors, a PRM of more than 2-3 cm for early gastric cancer and 5-6 cm for advanced gastric cancer is thought to be acceptable. Once the margin is confirmed to be clear, however, the length of PRM measured in postoperative pathologic examination does not affect the patient's survival, even when it is shorter than the recommended values. Hence, the recommendations for PRM length should be applied only to intraoperative decision-making to prevent positive margins on the final pathology. Given that a negative resection margin is the ultimate goal of determining an adequate PRM, development and improvement of reliable methods to confirm a negative resection margin intraoperatively would minimize the extent of surgery and offer a better quality of life to more patients. In the same context, special attention has to be paid to patients who have advanced stage or diffuse-type gastric cancer, because they are more likely to have a positive margin. Therefore, a wider excision with intraoperative frozen section (IFS) examination of the resection margin is necessary. Despite all the attempts to avoid positive margins, there is still a certain rate of positive-margin cases. Since the negative impact of a positive margin on prognosis is mostly obvious in low N stage patients, aggressive further management, such as extensive re-operation, is required for these patients. In conclusion, every possible preoperative and intraoperative evaluation should be thoroughly carried out to identify in advance the patients with a high risk of having positive margins; these patients need careful management with a wider excision or an IFS examination to confirm a negative margin during surgery.