Factors Identified That Influence Lymph Node Harvest During Esophagectomy by Thoracic Surgeons
Key findings
- In this study, a Society of Thoracic Surgeons database was used to determine the adequacy of lymph node assessment by specialized thoracic surgeons performing esophagectomy for primary esophageal cancer, as well as factors affecting lymph node yield
- Among 8,480 patients (465 surgeons; 215 hospitals), the median lymph node yield was 16, just above the 15-node threshold recommended by the National Comprehensive Cancer Network, and 57% of patients had at least 15 nodes harvested
- Higher yield was associated with higher T stage, treatment at higher-volume centers, and minimally invasive surgery, especially minimally invasive Ivor Lewis and minimally invasive three-hole approaches to esophagectomy
- Factors contributing to lower lymph node yield included female sex, low body mass index, prior thoracic surgery, squamous histology, and receipt of neoadjuvant treatment
- The only complication associated with higher lymph node yield was a slight increase in the risk of chyle leak (OR, 1.02; P=0.012)
In patients with primary esophageal cancer, a higher number of lymph nodes harvested during esophagectomy positively correlates with overall and disease-free patient survival.
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National Comprehensive Cancer Network guidelines recommend pathologic assessment of at least 15 lymph nodes for adequate nodal staging in patients who did not undergo neoadjuvant chemoradiation. The document adds that although the optimum number of nodes after preoperative treatment is unknown, the number of nodes resected should be similar.
A previous study of the National Cancer Data Base, published in Annals of Surgical Oncology, included surgeons across multiple specialties and found a median lymph node yield of only 12 (IQR, 7–19).
In this study, Uma M. Sachdeva, MD, PhD, and Christopher R. Morse, MD, surgeons in the Division of Thoracic Surgery at Massachusetts General Hospital, and colleagues have determined specialized thoracic surgeons produce better results. In Diseases of the Esophagus, they also detail patient-related, tumor-related and operative factors that contributed to higher or lower lymph node harvest.
Lymph Node Yield
The researchers used the General Thoracic Surgery Database of the Society of Thoracic Surgeons to analyze data on 8,480 patients who underwent esophagectomy for primary cancer by 465 surgeons (215 hospitals).
Reported lymph node yields ranged from 0–80 (median, 16; IQR, 11–22). The median yield was similar across the years of the study period, 2012 to 2016, and 57% of patients had 15 or more lymph nodes recovered.
Contributing Factors
In a multivariable model that accounted for variation across hospitals, factors significantly associated with lymph node yield were:
- Patient-related—Lower yield with female sex, body mass index <18.5 kg/m2, and prior cardiothoracic surgery
- Tumor-related—Lower yield with squamous cell histology and any neoadjuvant treatment; higher yield with stage T2 or T3 lesion
- Operative—Lower yield with intraoperative transfusion; higher yield with a minimally invasive approach
- Hospital volume—Higher yield at hospitals in the top three quartiles of esophagectomy volume, compared with the lowest quartile
Detail on Operative Approach
Open transhiatal esophagectomy recovered the lowest number of lymph nodes, and minimally invasive Ivor Lewis and minimally-invasive three-hole techniques harvested the highest number, regardless of tumor histology.
Overall, minimally invasive approaches to esophagectomy were associated with a significantly higher lymph node yield than open approaches (mean, 18.83 vs. 16.28; β, 1.31; P<0.001). Higher yields were not associated with longer operative times.
Perioperative Outcomes
Increasing lymph node yield was not associated with higher 30-day mortality, unexpected return to the operating room, recurrent laryngeal nerve injury, or anastomotic leak. The only notable complication was a slightly increased risk of postoperative chyle leak (OR, 1.02; P=0.012).
Commentary
In addition to the survival benefit of higher lymph node yield during esophagectomy, recent advances in chemotherapy or immunotherapy for node-positive disease have underscored the need for adequate lymphadenectomy. Minimally invasive surgery is a modifiable factor that can improve lymph node yield, the accuracy of pathologic staging, and the eligibility of patients for adjuvant treatment.
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