Impact of the number of lymph node examined on the prognosis of esophageal squamous cell carcinoma / 中华消化外科杂志

ABSTRACT

Objective To investigate the effect of the number of lymph nodes examined (NLNE) on the prognosis of esophageal squamous cell carcinoma (ESCC).Methods The retrospective case-control study was conducted.The clinicopathological date of 628 ESCC patients who underwent radical resection in the Tianjin Medical University Cancer Institute and Hospital from January 2005 to March 2013 was collected.Patients underwent radical resection of ESCC through right thorax.Observation indicators(1) surgical and postoperative pathological examinations;(2) follow-up and survival situations;(3) effect of NLNE on the prognosis of ESCC;(4) factors analysis affecting prognosis of ESCC patients;(5) subgroup analysis.Follow-up using outpatient examination,telephone interview and mail was performed to detect postoperative survival up to February 2018.Measurement data with skewed distribution were described as M (range).Receiver operating characteristic (ROC) curve analysis was used to determine the appropriate cut-off of the NLNE.The survival curve and survival rate were respectively drawn and calculated by the Kaplan-Meier method,and the survival analysis was done by the log-rank test.Multivariate analysis was done by the Cox proportional hazard model.Results (1) Surgical and postoperative pathological examinations472 and 156 patients underwent respectively Ivor-Lewis and Mckeown operations.There were 284 patients with tumor diameter ≤ 3.5 cm and 344 patients with tumor diameter ＞ 3.5 cm.The total NLNE was 11 139 for all of the 628 patients,with an average NLNE of 18 per case(range,2-78 per case) and a median NLNE of 16 per case.Of 628 patients,high-,moderate-and low-differentiated tumors were respectively detected in 48,469 and 111 patients;staging T0-1,T2,T3 and T4a of depth of tumor invasion in 30,119,260 and 219 patients;N0,N1,N2 and N3 of degree of lymph node metastasis in 349,173,69 and 37 patients;rN0,rN1,rN2 and rN3 of rate of lymph node metastasis in 349,184,54 and 41 patients.(2) Follow-up and survival situationsall the 628 patients were followed up for 3-144 months,with a median time of 36 months.The 1-,3-and 5-year survival rates were 82.4％,53.7％ and 41.3％,respectively.(3)Effect of NLNE on the prognosis of ESCCROC curve showed that the appropriate cut-off value of the NLNE was 16.Using NLNE =16 as a cut-off value,5-year survival rate was respectively 36.7％ in patients with NLNE ＜ 16 and 45.1％ in patients with NLNE ≥ 16,with a statistically significant difference in survival (x2 =9.527,P＜0.05).According to a median NLNE of 23,the patients with NLNE ≥ 16 were further divided into patients with 16 ≤ NLNE ≤ 23 and NLNE ＞ 23.Results showed that 5-year survival rate in patients with NLNE ＜ 16,16 ≤ NLNE ≤ 23 and NLNE ＞ 23 was respectively 36.7％,41.2％ and 50.3％,with a statistically significant difference in survival among them (x2 =10.588,P＜0.05),between patients with NLNE ＜ 16 and 16 ≤ NLNE ≤ 23 (x2 =4.419,P＜0.05).There was no statistically significant difference between patients with 16 ≤ NLNE ≤ 23 and NLNE ＞ 23 (x2 =1.413,P＞0.05).Five-year survival rate in patients with NLNE ≤ 23 and NLNE ＞23 was respectively 38.6％ and 50.3％,with a statisctically significant difference (x2 =5.885,P＜0.05).(4)Factors analysis affecting prognosis of ESCC patientsresults of univariate analysis showed that age,smoking history,BMI,tumor diameter,NLNE,depth of tumor invasion,degree and rate of lymph node metastasis were related factors affecting the prognosis of ESCC patients (x2 =5.454,4.875,7.669,10.691,10.588,30.612,59.780,76.565,P＜0.05).Results of muhivariate analysis showed that age,tumor diameter,NLNE,depth of tumor invasion and rate of lymph node metastasis were independent factors affecting the prognosis of ESCC patients [HR=1.268,1.300,0.762,1.354,1.357,95％ confidence interval (CI)1.034-1.556,1.038-1.629,0.662-0.878,1.183-1.549,1.089-1.692,P＜0.05].(5) Subgroup analysis:among 279 patients with lymph node metastasis,5-year survival rate in patients with NLNE ＜ 16,16 ≤ NLNE ≤ 23 and NLNE ＞ 23 was respectively 23.7％,19.4％ and 39.5％,with a statistically significant difference among them (x2 =8.397,P＜0.05),between patients with 16≤ NLNE ≤ 23 and NLNE ＞ 23 (x2=5.425,P＜0.05).There was no statistically significant difference between patients with NLNE ＜ 16 and 16 ≤ NLNE ≤ 23 (x2 =0.389,P＞ 0.05).Five-year survival rate in patients with NLNE ≤ 23 and NLNE ＞ 23 was respectively 21.9％ and 39.5％,with a statisctically significant difference (x2=7.942,P＜ 0.05).Among 349 patients without lymph node metastasis,5-year survival rate in patients with NLNE ＜ 16,16 ≤ NLNE ≤ 23 and NLNE ＞ 23 was respectively 45.6％,60.3％ and 59.2％,with a statistically significant difference among them (x2 =9.755,P＜0.05) and between patients with NLNE ＜ 16 and 16 ≤ NLNE ≤ 23 (x2 =8.208,P＜0.05).There was no statistically significant difference between patients with 16 ≤ NLNE ≤ 23 and NLNE ＞ 23 (x2 =0.284,P＞0.05).Five-year survival rate in patients with NLNE ≤ 23 and NLNE ＞ 23 was respectively 51.1％ and 59.2％,with no statisctically significant difference (x2 =1.147,P＞ 0.05).Conclusions The NLNE is an independent factor affecting the prognosis of ESCC patients,and at least 16 to 23 lymph nodes should be dissected.For patients with lymph node metastasis,and more than 23 lymph nodes should be dissected.For patients without lymph node metastasis,more than 23 lymph nodes dissection cannot obviously improve the prognosis of patients.