SAN DIEGO – Removing 12-20 lymph nodes for node-negative patients and 8-25 lymph nodes for node-positive patients confers a survival advantage in esophageal cancer, according to a data analysis of more than 2,100 patients.
"The maximum survival advantage was seen when a minimum of 15 lymph nodes were removed in node-negative patients and 20 in the node-positive patients," Dr. Kenneth L. Meredith said.
The Surveillance Epidemiology and End Results (SEER) analysis also revealed that the benefit of adjuvant radiation therapy on survival in esophageal cancer is limited to those with node-positive disease, suggesting that the management of esophageal cancer remains a work in progress, Dr. Meredith said at the annual Digestive Disease Week.
"Currently the treatment for these patients includes esophagectomy with or without neoadjuvant therapy," Dr. Meredith said. "There are many approaches to esophagectomy, and there are a multitude of recommendations for nodal clearance of these patients. If you look at single and multi-institutional database reviews, their recommendation for nodal harvest is anywhere from 6 to 40. We decided to perform a more recent analysis of the SEER database."
Dr. Meredith, chief of esophagogastric oncology and director of esophageal research at Moffitt Cancer Center, Tampa, Fla., and his associates queried the database for patients who underwent esophagectomy for cancer between 2004 and 2008. They identified 2,109 patients and categorized them by nodal harvest: greater than or less than 5, 8, 10, 12, 15, 20, 25, and 30.
Of the 2,109 patients, 467 were treated with adjuvant radiation and 1,642 were not. Patients treated with neoadjuvant radiation were excluded from the analysis, as were those who had histologic subtypes of cancer that were not adenocarcinoma or squamous cell carcinoma.
Dr. Meredith reported that use of adjuvant radiation was associated with decreased survival in patients with stage I disease (hazard ratio, 2.73; P less than .0001), no benefit in stage II (P = .075), increased survival in stage III (HR, 0.71; P = .005), and no benefit in stage IV (P = .913).
The median number of lymph nodes retracted from all patients was nine, "which is a little low by most standards," said Dr. Meredith.
Multivariate analysis revealed that among node-positive patients, the median survival with and without adjuvant radiation was 23 months and 20 months, respectively, and the 3-year survival rates were 34% and 26.7%, respectively (P = .023). Among node-negative patients, the 3-year survival with and without adjuvant radiation was 48.8% and 68.8%, respectively.
"The only lymph node cutoff we found was significant for all patients was that if you had more than five lymph nodes resected," Dr. Meredith said. "As you [removed more], lymph node harvesting did not translate into a survival benefit. However, when you subclassified whether they were node negative or node positive, a cutoff of 12 and 15, respectively, did translate into a survival benefit. In node-positive patients, those who had more than 8, 10, 12, 15, and 20 lymph nodes did translate into a survival benefit." He added that with regard to extended lymphadenectomy, or more than 20 lymph nodes resected in either cohort, no additional survival benefit was seen.
Dr. Meredith acknowledged certain limitations of the study, including its retrospective design and the fact that SEER lacks information on the nutritional status and performance status of patients. "There is also no information on margin status, chemotherapy, radiation dose, field design, and treatment technique," he said.
Dr. Meredith said that he had no relevant financial conflicts to disclose.