Objective:To study the influential factors on metastatic lymph nodes ratio(MLR) and the relationships between MLR and prognosis.
Methods:The clinical data of 121 patients with gastric adenocarcinoma were analysed. The receiving operating characteristic curve (ROC curve) was used to determine the cutoff of MLR and the CK20 immunihistochemical staining was used to detect the lymph nodes micrometastasis.
Results:The area under the ROC curve of MLR to predict the death of patients at 3-year or 5-year postoperatively was 0.826±0.053 and 0.896±0.046, so MLR=30.95% and MLR=3.15% were selected as the cutoffs. Then the MLR was classified furthermore into three groups: MLR1(MLR<3.15%), MLR2(3.15%≤MLR≤30.95%) and MLR3(MLR>30.95%). The survival curve showed that the higher the MLR value the lower survival period after radical operation (P=0.000). COX model showed the MLR was an independent prognostic factor (P=0.000). The MLR also discriminated subsets of patients with different 5-year survivals the same N stage (P<0.05). The MLR proved to be 34.7%(242/697) by HE staining and 43.5%(303/697) by CK staining respectively (P=0.001). Thus, the detection of micrometastasis by CK staining changed the MLR significantly. The lymph vessel invasion and depth of invasion was significantly related to the MLR.
Conclusions:The area under the ROC curve of MLR in predicting the death of patients at 3-or 5-years postoperatively is very large, and it seems to be a good way to determine the group cutoff. Therefore, the MLR seems to be meaningful parameter in detecting the prognosis of gastric adenocarcinoma. The detection of lymph nodes micrometastasis could change the MLR significantly.