[Comparison of the results of lymph node dissection via left versus right thoracotomy]

Up to now surgical treatment has been still the most effective treatment for esophageal cancer. However, postoperative lymph node recurrence is still a frequent event and affects long term survival considerably. The aim of this study is to compare the results of lymph node dissection via left vs. right thoracotomies and to verify whether there is any essential difference in lymphadenectomy between these two approaches.

Five hundred and fifty-nine cases with thoracic esophageal cancer were randomly selected from the database of esophageal cancer patients who underwent surgical treatment in our hospital between May 2005 and January 2011, including 282 cases through left thoracotomy and 277 cases through right thoracotomy. This series consisted of 449 males and 110 females with a mean age of 58.8 years (age range: 36 - 78 years). The pathological types were mainly squamous cell carcinoma (548 cases) and other rare types (11 cases). The data were analyzed and compared using Chi-square test. The P-value < 0.05 was considered as statistically significant. The actual 5-year survival rate was calculated based on the recent follow-up data of the patients who underwent surgery at least 5 years ago.

The average number of dissected lymph nodes was 23.4 via left versus 24.6 via right thoracotomies. The overall lymph node metastasis rate was 48.9% via left thoracotomy and 53.8% via right thoracotomy, and 34.8% vs. 50.5% in the chest (P < 0.001), 29.1% vs. 17.7% in the abdomen (P = 0.001). The pathologically confirmed lymph node metastasis rate was 45.9%, 44.0% and 34.9% in the upper, middle and lower segments of thoracic esophagus, respectively. The lymph node metastasis rates detected via left and right thoracotomy in the stage T1 cases were 14.7% (5/34) vs. 42.9% (12/28) (P < 0.001), and in the stage T2 cases were 35.4% (17/48) vs. 52.8% (28/53) (P = 0.007); in the station of para-thoracic esophagus were 9.6% vs. 13.4%, in the left upper mediastinum were 2.1% vs. 7.6%, and in the right upper mediastinum were 1.4% vs. 26.0%, respectively. The preliminary actual 5-year survival rate was 38.2% in the cases via left thoracotomy vs. 42.1% in those via right thoracotomy.

The results of this study demonstrate that lymph node dissection is more complete via right thoracotomy than via left thoracotomy, especially for the tracheoesophageal groove and para-recurrent laryngeal nerve nodes, which may eventually improve the survival of patients with esophageal cancer. Therefore, surgical treatment via right thoracotomy by Ivor-Lewis (two incisions) mode or Levis-Tanner (three incisions) mode with two-field or three-field complete lymph node dissection may become prevalent in the future.