Lymph node pick up by separate stations: Option or necessity?

Standard Lymphadenectomy for Esophageal and Lung Cancer: Variability in the Number of Examined Lymph Nodes Among Pathologists and Its Survival Implication

AIM

We compared variability in number of examined lymph nodes between pathologists and analyzed survival implications in lung and esophageal cancer after standardized lymphadenectomy.

METHODS

Outcomes of 294 N2 dissected lung cancer patients and 132 2-field dissected esophageal cancer patients were retrospectively examined. The primary outcome was difference in reported lymph node count among pathologists. Secondary outcomes were overall and disease-specific survival related to this count and survival related to the 50% probability cut-off value of detecting metastasis based on the number of examined lymph nodes.

RESULTS

The median number of examined lymph nodes in lung cancer was 13 (IQR 9-17) and in esophageal cancer it was 22 (18-29). The pathologist with the highest median number of examined nodes had > 50% higher lymph node yield compared with the pathologist with the lowest median number of nodes in lung (15 vs. 9.5, p = 0.003), and esophageal cancer (28 vs. 17, p = 0.003). Survival in patients stratified by median reported lymph node count in both lung (adjusted RMST ratio < 14 vs. ≥ 14 lymph nodes 0.99, 95% CI 0.88-1.10; p = 0.810) and esophageal cancer (adjusted RMST ratio < 25 vs. ≥ 25 lymph nodes 0.95, 95% CI 0.79-1.15, p = 0.612) was similar. The cut-off value for 50% probability of detecting metastasis by number of examined lymph nodes in lung cancer was 15.7 and in esophageal cancer 21.8. When stratified by this cut-off, no survival differences were seen.

CONCLUSION

The quality of lymphadenectomy based on lymph node yield is susceptible to error due to detected variability between pathologists in the number of examined lymph nodes. This variability in yield did not have any survival effect after standardized lymphadenectomy.

Lymphadenectomy: how to do it?

According to the more recent European guidelines, the D2 lymphadenectomy is considered the standard for curative intent treatment of patients with gastric cancer. Although, the surgical definition of D2 dissection and its technical aspects had been learned from Eastern surgeons in the past decades, some variations in the approach to D2 lymphadenectomy by European surgeons were detectable in randomized clinical trials dealing with lymphadenectomy. Despite in more recent years an improvement in surgical quality has been reported in European series, some differences in the practice of D2 dissection are thought to persist. As, these may contribute to discrepancies in gastric cancer survival observed across European countries, the standardization of surgical quality is an urgent need to improve the outcome of gastric cancer patients in Europe. In this manuscript, we focus on the technical aspects of the D2 dissection both in open and laparoscopic gastrectomy in order to contribute to the improvement of surgical care of gastric cancer in the West.