Metastatic Lymph Node Ratio in Advanced Gastric Carcinoma: A Better Prognostic Factor Than Number of Metastatic Lymph Nodes?
SY Lee, IS Hwang, YS Park, J Gardner, JY Ro. University of Ulsan College of Medicine, Asan Medical, Center, Seoul, Democratic Peoples Republic of Korea; University of Keimyung College of Medicine, Daegu, Democratic Peoples Republic of Korea; The Methodist Hospital, Weill Medical College, Cornell University, Houston, TX
Background: Gastric carcinoma is the most common cancer and the second most common cause of cancer-related death in Korea. Among the category I prognostic factors of gastric carcinoma, lymph node metastasis (nodal status) is considered to be the strongest prognostic factor. In the present study, we aimed to evaluate which lymph node assessment method, metastatic lymph node number vs. ratio of metastasis, was better to predict survival in comparison with known prognostic factors in advanced gastric carcinoma. In addition, we tried to determine what level of MLR was a statistically significant factor to get a meaningful separation of survival.
Design: 342 advanced gastric carcinoma patients who underwent radical gastrectomy and more than 15 lymph node dissection at Asan Medical Center, Korea in 2002 were included. The metastatic lymph node ratio (MLR) was calculated as the ratio between the number of metastatic lymph nodes and total dissected lymph nodes, and compared with conventional pN stage. The survival analysis was calculated according to the Kaplan-Meier method and compared by log-rank test.
Results: We demonstrated that the MLR was a simple and reproducible prognostic factor that supplemented the limitation of the conventional N staging system, and provided more accurate prognostic stratification in advanced gastric cancer. In addition to patients' age, tumor size, and chemotherapy, MLR was a strong prognostic factor in multivariate analysis, although the number of lymph node metastases,was not a strong factor. Moreover, with the relationship to pT stage, MLR showed better survival information than that of ordinary AJCC pN stage. We also proposed that the optimal cutoff values for MLR should be classified into four groups as follows: MLR0: 0, MLR1: 0-0.3, MLR2: >0.3-0.6, and MLR3: >0.6.
Conclusions: In conclusion, the MLR is a simple and reproducible prognostic factor that supplements the limitation of the conventional N staging system, and provides more accurate prognostic stratification in advanced gastric cancer. Based on the results above, we propose replacing pN staging system with MLR to provide both the patients and clinicians more evidence-based and accurate prognostic information.
Tuesday, March 23, 2010 1:00 PM
Poster Session IV # 62, Tuesday Afternoon