Dr George and colleagues from England investigated the relationship between survival in colorectal cancer and the number of lymph nodes examined by a pathologist.
The researchers used data from a cohort of 5174 colorectal cancer patients recruited between 1991 and 1994, and followed-up for 5 years.
The research team selected cases with data present on all prognostic variables, and stratified them into 3 groups by number of nodes examined.
The team made a multivariate survival comparison using a Cox regression model.
In all, there were 3592 cases with data present on all prognostic variables.
Patients who had more than 10 nodes identified had a significant survival advantage over those who had 5 to 10 identified.
|Reactive enlargement of lymph nodes reflect immune response to the tumor|
|British Journal of Cancer|
The team found that those who had 5 to 10 identified had a similar advantage over those with 0 to 4 identified.
The researchers noted that the effect was present in the whole group and at all Dukes' stages.
However, the team found that only Dukes' stages B and C were statistically significant.
The effect remained after adjustment in a Cox regression model in which the mean number of nodes taken out by each surgical firm did not predict survival.
In those with lymphocytic infiltration into the primary tumor, the team observed a survival advantage with prominent rather than mild infiltration.
The patients with prominent infiltration also tended to have more nodes found.
Dr George's team concludes, “Stage migration alone cannot explain these results, as survival advantages are noted across the whole population independent of stage.”
“Lymphocytic infiltration into the primary tumor is prognostically important, and is associated with the number of nodes found.”
“Reactive enlargement of lymph nodes in the mesentery may make them easier to find, reflect immune response to the tumor, and thus indirectly impact upon survival.”