Removal of more lymph nodes may lengthen survival in gastric cancer

Last Updated: 2015-05-21

By Rita Buckley

NEW YORK (Reuters Health) - A higher number of lymph nodes removed during resection for gastric adenocarcinoma confers a survival advantage in all but patients with advanced stage disease, according to new research.

Dr. George A. Poultsides, of Stanford University, Stanford Cancer Institute, in California, and colleagues analyzed survival outcomes in 742 consecutive patients who underwent surgical resection for gastric adenocarcinoma from 2000 to 2012 at seven academic medical centers participating in the U.S. Gastric Cancer Collaborative.

A total of 257 (35%) patients had seven to 15 lymph nodes removed and 485 (65%) had at least 16 lymph nodes removed, according to an article online May 5 in the Journal of the American College of Surgeons.

For the entire cohort, disease-specific survival was not significantly longer after removal of 16 or more lymph nodes (10-year, 55% versus 47%).

When patients with stages I-A through III-A were combined in a subset analysis, removal of 16 or more lymph nodes was associated with improved disease-specific survival (10-year, 74% vs. 57%, p=0.018). This survival advantage was not seen in patients with stages III-B and III-C disease.

In a subset analysis based on N stage, patients with N0-2 disease had improved disease specific survival after removal of at least 16 lymph nodes (10-year, 72% versus 55%, p=0.023). Patients with N3 disease did poorly, regardless of the number of lymph nodes removed.

Outcomes showed that in patients more likely to be true N0-2 (n=676), the hazard ratio significantly decreased as the number of lymph nodes removed increased, with no apparent incremental benefit beyond 16 lymph nodes.

In patients more likely to be true N3 (n=163), there was no significant correlation between the hazard ratio and the number of lymph nodes removed.

The findings are based on the use of sophisticated statistical methods to control for the phenomenon of stage migration as an underlying mechanism for the observations, corresponding author Dr. Poultsides told Reuters Health by email.

Dr. Jennifer F. Tseng, chief of the Division of Surgical Oncology at Beth Israel Deaconess Medical Center in Boston, who was not involved in the study, said that the findings are still subject to some possibility of residual confounding.

"The authors used a number of strategies to reduce bias in the study," she told Reuters Health by email, "but it was not a randomized controlled trial."

According to Dr. Poultsides, the outcomes corroborate evidence from a 15-year follow-up of a Dutch randomized trial and a randomized trial from Taiwan.

"Our findings solidify the current recommendation to examine at least 16 lymph nodes during gastric adenocarcinoma resection to optimize staging," he said. "So far, this recommendation has merely been based on expert consensus opinion, but not on higher level evidence."

The authors reported no funding or disclosures.

SOURCE: http://bit.ly/1cQxMSM

J Am Coll Surg 2015