ORLANDO – Tumor response nodes obtained from patients who undergo esophagectomy for early-stage adenocarcinoma provide valuable prognostic information, according to Dr. Dylan Nieman.
Such nodes – lymph nodes with evidence of neoadjuvant treatment effect without residual cancer cells – may mark the prior spread of tumor, and should be counted as positive, Dr. Nieman of the University of Rochester (N.Y.) said at the annual meeting of the Society of Thoracic Surgeons.
The current practice of ignoring these nodes likely results in systematic pathologic understaging, he explained.
In 90 patients who underwent esophagectomy after neoadjuvant therapy for esophageal adenocarcinoma, the median number of nodes found per resection specimen was 18. A total of 100 tumor response nodes without viable malignant cells were identified in 38 (42%) of the patients.
The majority of the patients with treatment response nodes had only one node detected, Dr. Nieman said.
The median survival for the entire cohort was 55.6 months, and the 5-year survival was 35%. The median survival of patients with evidence of treatment response nodes was poorer, but not significantly different from those without treatment response nodes (45.9 vs. 55.6 months), he noted.
"However, for a subset of 62 patients classified as having limited or no nodal involvement – that is, AJCC N0 or N1 – the presence of treatment response nodes was associated with significantly poorer survival. This effect remained when adjusting for patient age and [American Joint Committee on Cancer] stage (hazard ratio, 2.7)," he said.
In a subset of 46 patients with pathologic AJCC stage 2B or less, the presence of treatment response nodes was still associated with poorer survival, even after adjustment for age and AJCC stage.
"To look at this a different way, if tumor response nodes were to be counted as positive, the nodal status of 29 of these patients would be upstaged. This includes 18 of 39 patients, or 46%, who were classified as node negative, and 8 of 23 patients, or 34%, who were classified as N1 by AJCC pathological assessment," he said.
The recategorization of those 29 patients resulted in better survival for the entire group, but particularly for those in the lowest-stage group, he noted.
When investigators modeled stage-adjusted survival, the counting of tumor response nodes as positive offered a better model fit, compared with following the current practice of ignoring tumor response nodes, he explained.
Patients included in the study were identified from a prospectively collected clinical database of esophagectomy patients, and were treated with neoadjuvant therapy for esophageal adenocarcinoma between 2006 and 2011. Most (82 of 90) were men. The patients had a mean age of 62 years, and were followed for a median of 27 months. Forty patients received preoperative chemotherapy, and 50 received preoperative chemoradiation.
In all cases, pathologic resection margins were negative.
On pathologic review, the majority had T3 tumors. More than 40% were staged as node negative, and more than two-thirds were staged with N0 or N1 disease.
"Prior to neoadjuvant therapy, all of these patients were clinically staged stage 2 or stage 3, but at the time of resection after neoadjuvant therapy, by AJCC staging, 24% of the patients were stage 0 or 1, 27% were stage 2, and almost half were stage 3," he said.
The findings are notable, because the current AJCC pathologic staging for esophageal adenocarcinoma is derived from the experience of patients undergoing esophagectomy alone. This approach has unclear relevance in patients who receive multimodality therapy, which has supplanted primary surgery as the standard of care for locoregionally advanced esophageal adenocarcinoma, he said.
"Future efforts at revising the staging system for esophageal adenocarcinoma should consider treatment response lymph nodes. ... We currently have pathological staging models that are of limited usefulness for our neoadjuvantly treated population. Perhaps consideration of these nodes can help improve that," he concluded.
Dr. Nieman reported having no financial disclosures.