Contributing factors to lymph node recovery with esophagectomy by thoracic surgeons: an analysis of the Society of Thoracic Surgeons General Thoracic Surgery Database

Given the association between lymphadenectomy and survival after esophagectomy, and the ongoing development of effective adjuvant protocols for identified residual disease, we determined factors contributing to lymph node yield and effects on postoperative morbidity following esophagectomy by thoracic surgeons. Using the Society of Thoracic Surgeons General Thoracic Surgery Database, all patients who underwent esophagectomy for primary esophageal cancer with gastric conduit reconstruction from 2012 to 2016 were identified. Patient demographics, technical factors, and tumor characteristics associated with lymph node yield were determined using a multivariable multilevel mixed-effects regression model. Associations between lymph node yield and perioperative morbidity and mortality were similarly assessed. A total of 8480 patients were included. The median number of nodes harvested was 16 [Interquartile Range 11-22]. Factors associated with fewer nodes included female gender (b=-0.53, P=0.032), body mass index <18.5 (b=-1.46, P=0.012), prior cardiothoracic surgery (b=-0.73, P=0.015), intraoperative blood transfusion (b=-1.43, P<0.001), squamous cell histology (b=-0.86, P=0.006), and neoadjuvant treatment (b=-1.41, P<0.001). Operative approach significantly affected lymph node yield, with minimally invasive approaches demonstrating higher lymph node counts, and open transhiatal esophagectomy recovering the fewest nodes. Findings were independent of clinical center. There was no association of higher lymph node yield with 30-day mortality, with only slightly increased risk for chyle leak (odds ratio [OR] 1.02, P=0.012). In conclusion, several patient and tumor factors affect lymph node recovery with esophagectomy, independent of hospital center. Technical aspects, specifically minimally invasive approach, play a significant role in quantified lymph node yield. Higher operative lymph node yield was associated with minimal increased morbidity.