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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 examinations:472 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 situations:all 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 ESCC:ROC 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 patients:results 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.
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Objective To compare the clinical efficacy of Da Vinci robot-assisted esophagectomy and combined thoracoscopy-and laparoscopy-assisted esophagectomy for esophageal cancer.Methods The retrospective cohort study was conducted.The clinicopathological data of 116 patients who underwent minimally invasive radical resection of esophageal cancer in the Shanghai Chest Hospital of Shanghai Jiaotong University between November 2015 and September 2016 were collected.Fifty-eight patients undergoing combined thoracoscopy-and laparoscopy-assisted esophagectomy and 58 undergoing Da Vinci robot-assisted esophagectomy were respectively allocated into the thoracoscopy-and laparoscopy-assisted and Da Vinci robot-assisted groups.Patients received esophagectomy by right thorax-left cervico-abdominal triple incisions,thorax-cervico 2-field lymph node dissection of esophageal cancer and digestive tract reconstruction via assisted incision.Observation indicators:(1) surgical and postoperative situations;(2) follow-up and survival situations.Follow-up using outpatient examination and telephone interview was performed to detect the survival of patients and tumor recurrence or metastasis up to March 2017.Measurement data with normal distribution were described as (x)±s.Measurement data with skewed distribution were described as M (range).Comparison between groups was analyzed by the nonparametric test,and comparisons of count data were done by the chi-square test and Fisher's exact probability.Results (1) Surgical and postoperative situations:all patients received successful surgery,without conversion to open surgery.The number of lymph nodes dissected along the recurrent laryngeal nerve (RLN) and duration of postoperative hospital stay were 2.8±2.2,13 days (range,9-131 days) in the thoracoscopy-and laparoscopy-assisted group and 4.8±3.7,11 days (range,7-81 days) in the Da Vinci robot-assisted group,respectively,with statistically significant differences between the 2 groups (t =3.480,Z =2.361,P＜0.05).The total operation time,numbers of patients with overall complications,anastomotic leakage,injury of the RLN,pleural effusion,pulmonary infection,respiratory failure,chylothorax,arrhythmia and tracheoesophageal fistula were respectively (276±61)minutes,24,15,7,6,5,4,2,1,0 in the thoracoscopy-and laparoscopy-assisted group and (261±50)minutes,21,8,10,4,2,2,1,1,1 in the Da Vinci robot-assisted group,with no statistically significant difference (t =1.296,x2 =0.327,2.657,0.620,0.438,1.368,0.703,0.342,1.009,P＞0.05).Some of the patients had postoperative multiple complications.Patients with anastomotic leakage received local dressing changes,continuous gastrointestinal decompression and vacuum aspiration.The pronunciation and bucking response were observed in patients with injury of the RLN (unilateral injury).Patients with pleural effusion received pleural puncture fluid or closed thoracic drainage.Patients with pulmonary infection underwent antibiotic therapy and regular aerosol inhalation.Patients with respiratory failure underwent tracheotomy and assisted breathing with ventilator.Patients with chylothorax received fasting and closed thoracic drainage.Patients with arrhythmia were treated by drug.Patients with tracheo-esophageal fistula underwent conservative treatment.All the patients with complications were improved or cured.There were no wotmd infection,deep venous thrombosis of lower extremity,pulmonary embolism,reoperation and death within 30 days postoperatively in patients of 2 groups.(2) Follow-up and survival situations:all the 116 patients were followed up for 5-15 months,with a median time of 8 months.Numbers of patients with tumor-free survival,tumor recurrence and tumor metastasis were 50,6,4 (2 with simultaneous tumor recurrence and metastasis) in the thoracoscopy-and laparoscopy-assisted group and 51,5,4 (2 with simultaneous tumor recurrence and metastasis) in the Da Vinci robot-assisted group,respectively,showing no significant difference between the 2 groups (x2=0.077,1.000,P＞0.05).Conclusions Da Vinci robot-assisted esophagectomy is safe and feasible in the treatment of esophageal cancer.Compared with combined thoracoscopy-and laparoscopy-assisted esophagectomy,Da Vinci robot-assisted esophagectomy has comparable operation time,and is associated with a greater yield of lymph nodes along the RLN.