TUESDAY, July 22 (HealthDay News) -- Patients with stomach or pancreatic cancer may have more lymph nodes examined for the spread of cancer if they're treated at designated comprehensive cancer centers or at hospitals that do a high number of cancer surgeries, says a U.S. study.

If too few lymph nodes are examined for cancer cells, a patient's cancer may be incorrectly classified, altering prognosis, treatment decisions and eligibility for clinical trials, according to background information in the study. Current guidelines for stomach and pancreatic patients recommend examination of at least 15 regional lymph nodes.

The researchers examined National Cancer Data Base records of 3,088 stomach cancer patients and 1,130 pancreatic cancer patients. Of the stomach cancer patients, 11.6 percent had surgery at a hospital designated as a National Cancer Institute (NCI) comprehensive cancer center or as part of the National Comprehensive Cancer Network (NCCN-NCI hospitals), 34 percent had surgery at other academic hospitals (affiliated with a medical school but not designated as NCCN-NCI facilities), and 54.4 percent had surgery at community hospitals.

Of the pancreatic cancer patients, 19 percent had surgery at NCCN-NCI hospitals, 43.3 percent at other academic hospitals, and 37.7 percent at community hospitals.

"Patients undergoing surgery had more lymph nodes examined at NCCN-NCI hospitals than at community hospitals [median [midpoint], 12 vs. six for gastric cancer and nine vs. six for pancreatic cancer]," wrote Dr. Karl Y. Bilimoria, of the American College of Surgeons and Feinberg School of Medicine at Northwestern University in Chicago, and colleagues. "Patients at the highest-volume hospital had more lymph nodes examined than patients at low-volume hospitals [median, 10 vs. six for gastric cancer and eight vs. six for pancreatic cancer]."

Overall, 23.2 percent of stomach cancer patients and 16.4 percent of pancreatic cancer patients had at least 15 lymph nodes evaluated, the study said. Patients at high-volume or NCCN-NCI hospitals were more likely to have at least 15 lymph nodes examined than patients at community or low-volume hospitals.

The study was published in the July issue of the Archives of Surgery.

"Nodal status is a powerful predictor of outcome, and every reasonable attempt should be made to assess the optimal number of lymph nodes to accurately stage disease in patients with gastric [stomach] and pancreatic cancer," the researchers wrote. "Moreover, differences in nodal evaluation may contribute to improved long-term outcomes at NCCN-NCI centers and high-volume hospitals for patients with gastric and pancreatic cancer."

More information

The American Cancer Society has more about stomach cancer.