Regional lymph node involvement is one of the most important predictors of survival for patients with esophageal cancer.
The current staging classification differentiates only between the presence and absence of lymph node metastasis.
Dr Alexander Greenstein and colleagues from the USA examined whether involvement of a higher number of lymph nodes is associated with worse survival among esophageal cancer patients.
The research team identified 838 patients who underwent operations for node-positive esophageal cancer between 1988 and 2003 from the Surveillance, Epidemiology and End Results cancer registry.
|A higher lymph node ratio was associated with worse disease-specific survival|
|Journal of the American College of Surgeons |
The team reported that the number of positive lymph nodes is confounded by the total number of lymph nodes removed.
Patients were therefore classified into 3 groups by the ratio of positive-to-total number of lymph nodes removed, lymph node ratios of 0.2, 0.21 to 0.5, and over 0.5.
Esophageal cancer-specific survival was compared among these groups using Kaplan-Meier curves.
Stratified and Cox regression analyses were used to evaluate the relationship between the lymph node ratio and survival after adjusting for potential confounders.
Disease-specific survival rates decreased with higher lymph node ratio.
The researchers found that the 5-year disease-specific survival was 30% among patients with an lymph node ratio of 0.2.
The team noted that the 5-year disease-specific survival was 16% and 13% for those with lymph nodes of 0.21 to 0.5, and over 0.5, respectively.
The team then conducted stratified and multivariable analyses controlling for age, race, gender, histology, tumor-status, and postoperative radiotherapy.
The researchers observed that a higher lymph node ratio was independently associated with worse disease-specific survival.
Dr Greenstein's team concluded, "These data suggest that a higher lymph node ratio among patients with node-positive esophageal cancer is associated with worse survival."
" If validated, this prognostic criterion may be included in staging classifications."