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Examined lymph node count improves staging, OS in NSCLC
A higher number of examined lymph nodes resulted in more accurate node staging and improved long-term survival among patients with non–small cell lung cancer, according to analyses of U.S. and Chinese databases.
“Patients with positive lymph node metastasis have a higher risk of disease recurrence; thus, lymph node involvement is one of the most important determinants for both prognosis and decisions about treatment strategy in patients with resectable NSCLC,” Wenhua Liang, MD, of The First Affiliated Hospital of Guangzhou Medical University, and colleagues wrote. “Precise staging is the key to appropriate delivery of adjuvant therapies. Some studies have shown a correlation between the number of examined lymph nodes and long-term survival, but the results of these studies are contradictory.”
Researchers reviewed the U.S. SEER database (n = 38,806) and a multi-institutional registry from China (n = 5,706) to identify stage I to stage IIIA resected NSCLC cases between 2001 and 2008. Liang and colleagues then used multivariable models to analyze the relationship between examined lymph node count, stage migration and OS.
The Chinese registry showed a median examined lymph node count of 15, compared with the SEER database count of seven. There were 1,897 deaths over 3.6 years of median follow-up in the Chinese database and 17,029 deaths over a median 5 years of follow-up in the SEER database.
After researchers adjusted for T stage, tumor location, histology and tumor type, both databases showed that N stage increased proportionally with examined lymph node count (SEER: OR = 1.038; 95% CI, 1.035-1.041; China: OR = 1.012; 95% CI, 1.006-1.019).
Linear regression showed higher examined lymph node counts were associated with a greater number of positive lymph nodes (R2 = 0.917; P < .001).
Examined lymph node count correlated with improved OS in both node-positive disease (SEER: HR = 0.989; 95% CI, 0.986-0.992; China: HR = 0.984; 95% CI, 0.977-0.99) and node-negative disease (SEER: HR = 0.986; 95% CI, 0.983-0.989; China: HR = 0.981; 95% CI, 0.972-0.989).
Liang and colleagues wrote that the findings were limited by the retrospective study.
“In conclusion, a greater number of examined lymph nodes is associated with more accurate node staging and better long-term survival of resected NSCLC,” the researchers wrote. “We recommend 16 examined lymph nodes as the cut point for the evaluation of the quality of postoperative lymph node examination or prognostic stratification for patients with declared node-negative disease.” – by Andy Polhamus
Disclosure: Liang reports no relevant financial disclosures. Please see the study for a full list of all other researchers’ relevant financial disclosures.