Does lymph node ratio affect prognosis in gastroesophageal cancer?

• Current N staging system for gastroesophageal cancers rely on absolute number of positive lymph nodes, which is determined not only by tumor biology but also by the extent of lymph node dissection. For example, a gastric cancer classified as N1 after limited lymph node dissection may have been classified as N2 or N3 if a more extensive lymphadenectomy was performed, a phenomenon called “stage migration.” Therefore, N stage may be influenced by the surgeon’s attitude toward the lymph node dissection, especially in Western countries where D1 lymph node dissection remains an accepted treatment modality.
• Use of LNR (ratio between the absolute number of metastatic lymph node and the total number of lymph nodes harvested at the time of gastric resection) instead of absolute number of positive lymph nodes may minimize stage migration.
• Use of LNR has not been extensively validated in a US population. Our study confirms that LNR can be effectively used as a prognostic indicator in a US population of patients undergoing resection of gastroesophageal cancer. Furthermore, to our knowledge, our study is the first to report specifically on relationship of LNR with status of resection margins.

BackgroundIncreasing evidence suggests that the ratio of number of nodes harboring metastatic cancer to the total number of lymph nodes examined (lymph node ratio, LNR) may affect survival after esophagogastric resection for cancer. We analyzed the impact of LNR in overall survival in patients undergoing esophagogastric resection for cancer.MethodsPatients who underwent gastroesophageal resection for cancer (1998 to 2008) were categorized into 4 groups according to their LNR: 113 patients had negative nodes (N0), 86 LNR less than .3, 40 LNR .31 to .6, and 47 LNR greater than .6. Study endpoint was overall median survival.ResultsHigher LNR was associated (P < .001) with more advanced stage and adverse pathologic features (eg, grading, venous/perineural invasion). Multivariate analysis demonstrated that LNR is an independent predictor of survival.ConclusionIn our experience, LNR correlates with adverse pathologic features and is a negative prognostic factor in patients undergoing radical resection for gastroesophageal cancer.