| Objective: Gastric cancer(GC)is one type of extremely malignant neoplasm of digestive tract.Besides,it is also the fifth most common carcinoma in this world.The numbers of newly diagnosed patients with gastric carcinoma is increasing year by year due to the aggravation of environmental pollution,the increase of population base,changes in dietary habits,the aggravation of the aging trend of society,and gastroscopy is included in physical examination.At present,surgery is an essential part of the process of curing gastric cancer,patients need to be pathological staged after surgery.Accurate staging of gastric cancer after surgery is critical to patients with gastric cancer.Which involves evaluating the state of the disease,selecting an appropriate adjuvant treatment,and predicting the prognosis.At present,a number of studies have confirmed that there is a stage migration phenomenon in the p N staging system of the TNM staging system(AJCC/UICC)which based on the number of lymph node metastases.In addition,the lymph node metastasis ratio(MLNR)can reduce the stage migration phenomenon of PN staging in TNM staging.Which caused by the number of positive lymph nodes detected increased or decreased due to various factors such as technical differences of the surgeon and difficulty in lymph node sorting.However,it is still not known for the associated among the rate of lymph node metastasis with postoperative staging with prognosis of gastric cancer.The associated among lymph node metastasis rate with progression-free survival,with overall survival,with tumor recurrence after radical gastrectomy was included.There are still controversies about the scope of surgical resection and lymphatic root scan for upper gastric cancer and esophagogastric junction cancer,such as whether it is necessary to clean the hilar lymph nodes.Therefore,this study only probe into the relevancy between lymph node metastasis rate and patients after radical resection of distal gastric cancer.The purpose of this study was to analyze the associated between the ratio of lymph node metastasis and patient outcomes under different p TNM stages after radical gastric cancer surgery.So as to it can provides a theoretical basis for accurate pathological staging,adjuvant treatment selection and prognosis evaluation of patients with distal gastric cancer after radical surgery.Methods: A total of 408 patients who were diagnosed with distal gastric cancer by imaging examination and pathological examination at the First Affiliated Hospital of Southwest Medical University from January 2010 to January 2014 were included in our study.Each patients included in this research were followed up,the content of the follow-up includes the patient’s overall survival,current status,and recurrence,etc.The follow-up was as of August 1,2020.Collect the clinical datas of the patient,included gender,age,tumor size(calculated according to the largest diameter),the level of tumor differentiation,the depth of stomach wall of tumor invasion,the overall number of dissected lymph nodes,whether the tumor has invaded vascular,the gross amount of metastatic lymph nodes,whether the tumor has invaded nerves,the gross amount of negative lymph nodes,whether there are cancer nodules around the tumor,the gross amount of dissected lymph nodes in each group,the gross amount of metastatic lymph nodes in each group,p TNM,overall survival.We figure up the rate of lymph node metastasis for each sickness.Proportion of sick person with lymph node metastasis for each group and percentage of lymph node metastasis for each group were figure up.SPSS 24.0 statistical software was used to perform statistical analysis.the relevancy between dissection of lymph nodes and metastatic lymph nodes was performed through the Spearman rank correlation coefficient.For the factors affecting the prognosis,univariate analysis was performed by Kaplan-Meier method and Log-rank.Multivariate analysis was performed through the COX proportional hazard model.For element which impact the prognosis,univariate analysis of prognostic factors was executed through Kaplan-Meier and Log-rank methods.Multivariate analysis was executed through cox proportional hazards model.Among them,the optimal critical value of lymph node metastasis ratio is calculated as follows,set the assumed critical value,0.05;0.10;0.15;0.20;0.25;0.30;0.35;0.40;0.45;0.50,etc,stack 0.05 each time,gradually stack until 1.00.Then divide each hypothetical critical value into two groups(one group is less than the marginal value;the other one is equal or greater than the marginal value).Next,we adopt the Kaplan-Meier method to survival analysis for the two groups of patients,and we rely on χ~2 test to compare the two groups of measurement datas,every assumptive marginal value will be statistically analyzed.When there is a boundary between a statistically significant(p<0.05)and a non-statistically significant(p≥0.05)hypothetical critical value group,the hypothetical critical value is the true critical value,and a survival curve is drawn.Result: A amount of 408 patients were collected in this study.Among them,272 were males(66.7%)and 136 females(33.3%);age range 35-83 years(58.30±10.63);tumor size 4.55±1.87cm;48 cases of p T1 stage(11.8%),48 cases of p T2 stage(11.8%),280 cases of p T3 stage(68.6%),32 cases of p T4 stage(7.8%);136 cases were moderately and well differentiated(33.3%),272 cases were poorly undifferentiated(66.7%);164 cases of invasion of blood vessels(40.2%),244 cases(59.8%)without vascular invasion;164 cases of nerve invasion(40.2%),244 cases(59.8%)without nerve invasion;36 cases(8.8%)exist cancer nodules around the tumor,372 cases(91.2%)without cancer nodules around the tumor;according to p TNM staging,60 cases were in stage Ⅰ(14.7%),72 cases were in stage Ⅱ(17.6%),and 276 cases were in stage Ⅲ(64.7%);the gross amount of eradicative lymph nodes ranges from 12 to 73(31.88±10.809);the gross amount of metastatic lymph nodes ranges from 0-32(7.55±8.102);lymph node metastasis rate ranged from 0 to 0.911(0.230±0.231).According to the statistics,the proportion of sick person with lymph node metastasis for each group from high to low was N0.6 group(39.73%),N0.3 group(33.02%),N0.5 group(27.98%),N0.4D group (25.00%),N0.8A group(23.88%)and N0.7 group(19.02%).The percentage of lymph node metastasis for each group from high to low was N0.3 group(22.32%),N0.6 group(21.87%),N0.5 group(21.36%),N0.4D group(18.23%),N0.8A group(12.62%),N0.7 group(11.47%),N0.1 group(10.83%),N0.9 group(7.12%),N0.14 V group(6.34%),N0.12 A group(6.27%),N0.11 P group(5.53%).Through Spearman’s rank correlation coefficient analysis,we found that as the gross amount of lymph nodes eradicated by surgery increases,the gross amount of metastatic lymph nodes detected also gradually increases,showing a positive correlation(rs=0.1665;P = 0.0001).As gross amount number of negative lymph nodes eradicated by surgery increased,the corresponding lymph node metastasis rate decreased gradually,showing a negative correlation(rs=-0.002145;P = 0.0329).With the increase or decrease of the gross amount of surgically eradicated dissected lymph nodes,the rate of lymph node metastasis appear irregularly,representing no correlation(rs=0.0019;P = 0.0605).The univariate analysis of prognostic factors used Kaplan-Meier and Log-rank methods,gender(χ~2=0.356;P=0.551),age(χ~2=0.875;P=0.349),nerve invasion(χ~2=3.536;P=0.06)were non-prognostic factors,tumor size(χ~2=9.73;P=0.002)),cancer nodules(χ~2=4.364;P=0.037),the gross amount of lymph nodes dissected(χ~2=143.148;P=0.001),depth of tumor invasion(χ~2=21.429;P=0.001),vascular invasion(χ~2=5.313;P =0.021),degree of tumor differentiation(χ~2=5.981;P=0.04),gross amount of positive lymph nodes(χ~2=206.193;P=0.001),lymph node metastasis ratio(χ~2=320.728;P=0.001),p TNM staging(χ~2=25.109;P=0.001)are all factors that affect the prognosis;The COX proportional hazards model was adopted to execute the multivariate analysis of prognostic factors,tumor size(χ~2=0.414;P=0.023),depth of tumor invasion(χ~2=0.390;P=0.012),degree of tumor differentiation(χ~2=0.403;P=0.041),gross amount of metastatic lymph nodes(χ~2=0.027;P=0.011),lymph node metastasis ratio(χ~2=1.209;P=0.001),p TNM staging(χ~2=0.334;P=0.001)are all independent prognostic factors.The optimal cut-off value of lymph node metastasis ratio is calculated by Kaplan-Meier method,we conducted something below:without distinguishing p TNM staging,the overall survival rate of lymph node metastasis rate≥0.15 and lymph node metastasis rate<0.15 is statistically significant;p TNM= Phase I,there was no statistically significant lymph node metastasis rate could be calculated;p TNM=Phase II,the overall survival rate of lymph node metastasis rate≥0.14 and lymph node metastasis rate<0.14 is statistically significant;p TNM=Phase III,the overall survival of lymph node metastasis ratio≥0.10 and lymph node metastasis rate <0.10 is statistically significant.Conclusion: There was a obvious relevance between lymph node metastasis ratio and patient’s prognosis after distal gastric cancer surgery.the lymph node metastasis ratio was ≥0.15 without distinguishing p TNM stage;lymph node metastasis rate≥0.14 with p TNM= stage II;lymph node metastasis rate ≥ 0.10 with p TNM=stage II,the overall survival of the patients was poor.Based on univariate analysis,we conclude that gender,age,and neurological invasion are non-influencing factors for prognosis,tumor size,cancer nodules,total number of lymph nodes dissected,the depth of stomach wall of tumor invasion,neoplasm has invaded vascular,the level of neoplasm differentiation,the gross amount of metastatic lymph nodes,lymph node metastasis rate,p TNM stage are all factors affecting prognosis.We can concluded through multivariate analysis that neoplasm size,the depth of neoplasm invasion of the gastric wall,the level of neoplasm differentiation,the gross amount of metastatic lymph nodes,lymph node metastasis rate,and p TNM stage all were independent prognostic factors.The lymph nodes of distal gastric cancer group N0.3,N0.6,N0.5,N0.4D,N0.8A and N0.7 had a high metastasis rate,so we should pay more attention to complete dissection during surgery.As the gross amount of lymph nodes of surgically eradicated increased,the gross amount of metastatic lymph nodes detected gradually increased;as the gross amount of negative lymph nodes of surgically eradicated increased,the corresponding value of lymph node metastasis ratio gradually decreased.Which appears that standard lymph node dissection can enhance the amount of discovery of metastatic lymph nodes;and increasing the discovery of negative lymph nodes eradicated by surgery can reduce the corresponding lymph node metastasis rate. |
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