Two-field Lymph Node Dissection For Squamous Cell Carcinoma Of The Lower Thoracic Esophagus: A Comparison Of Clinical Outcomes Between Ivor Lewis Approach And Sweet Approach

Objective To retrospectively compare the clinical outcomes of patients with lower thoracic esophageal squamous cell carcinoma by two different approachs (Sweat vs Ivor Lewis) in two-field lymph node dissection.Methods From January 1999 to December 2001, Eighty-nine patients with lower throcic esophageal squamous cell carcinoma underwent transthoracic esophagectomy with 2-field lympn node dissection in our department. All cases were retrospectively analyzed. Of these patients, fifty-eight underwent esophagectomy by Ivor Lewis approach involving initial midline laparotomy for mobilization of the stomach and upper abdominal lymphadenectomy followed by a right-sided posterolateral thoractomy allowing resection of the esophagus and mediastinal lymphadenectomy,, and 31 by Sweet approach solely involving left-sided posterolateral thoractomy for mobilization of the stomach, resection of the esophagus,and upper abdominal and mediastinal lymph node dissection as well. In all cases, the esophagus was replaced by the stomach for gastrointestinal reconstruction.The clinical and pathological characteristics of the study group were summarized. Operation time, bleeding volume, number of resected nodes,post-operative course and morbidity rates were compared between two types of approach.The median follow up period of all patients was 36 months(range, 5-79), that for the 31 suvivor being 54 months(range, 40-79). Suvival time was measured from the tine of surgery to death from any cause or to the time of the last follow up visit, with none lost to follow up.The statistical calculations were conducted with SPSS 13.0 software package. Students t-test was used for continous data. The x² or Fishers exact tests were employed to compare categorical data. Suvival curves were constructed by Kaplan-Meier method, and the log-rank test was used to determine significance. P value below 0.05 were considered to indicate statistical significance.Results There were no significant difference in clinical and pathological characteristics between two types of approach. There wre more mediastinal lymph nodes dissected (19.59±6.61 vs 4.97±4.81)(P=0.000), longer time consumed (242.41±36.94min vs 198.06±34.71min)(P=0.000) and higher upper mediastinal lymph node metastatic rate (3.2% vs 17.2%)(P=0.039)through Ivor Lewis approach than through Sweet approach. The number of dissected upper abdominal lymph nodes, postoperative courses, complications ,and middle and lower mediastinal lymph node metastatic rate didn't differ from each other significantly. For 89 patients the positive lymph nodes were found in 61 patients(68.5%).The prevalence of lymph node metastasis increased with increasing tumor infiltration depth insignificantly(P=0.068);while in T₃-T₄stage,the prevalence was significantly higher than that in T₁-T₂ stage(P=0.012).The 3-year survival rate was 63.8% and 35.5% with Ivor Lewis approach and with Sweet approach, respectively(P=0.058). For NO patients , the 3-year survival was 100% and 40%(P=0.008);and for N1 patients,was 47.5% and 33.3%(P=0.49) with Ivor Lewis approach and with Sweet approach, respectively.Conclusion In 2-field lymph node dissection for squamous cell carcinoma of the lower thoracic esophagus, Ivor Lewis approach provides more appropriate extent of lymphodenectomy and better survival benefit compared to Sweet approach.