Current quality initiatives call for examination of at least 12 lymph nodes in curative colon cancer resections. The aim of this study was to determine if the number of nodes harvested has increased, and if the increased number nodes correlates with improved staging or overall survival.
A review of the Surveillance, Epidemiology, and End Results program database from 2004−2010 was performed. All patients who underwent colon cancer resection during this date range were analyzed. Number of nodes retrieved, patient stage, overall survival, and overall survival by stage were examined. Multivariable analysis controlled for stage, cancer site, age, year of diagnosis, and number of nodes retrieved. Improved staging was defined as increased detection of stage III patients.
A total of 147,076 patients met inclusion criteria. Median number of nodes analyzed increased sequentially with each year examined, from 12 in 2004 to 17 in 2010. Despite greater number of total nodes obtained and analyzed, there was no increase in the percentage of patients with positive nodes (stage III disease). On multivariable analysis, after controlling for stage, site of disease, age, and year of diagnosis, there was a slight overall survival benefit with increasing nodal retrieval (hazard ratio = 0.987 for each additional node removed; 95% CI, 0.986−0.988; p < 0.001).
Since quality initiatives have been put in place, there has been an increase in the number of nodes examined in colon cancer resections, but no improvement in staging. The improved survival seen with higher node counts was independent of stage, site of disease, patient age, and year of diagnosis.