In this study, physicians from the United States evaluated the relationship between survival and the number of lymph nodes analyzed from surgical specimens, in patients with colon cancer.
The team performed a secondary analysis on 3411 patients from the Intergroup Trial INT-0089. This is a trial of adjuvant chemotherapy in high-risk patients with stage II and stage III colon cancer.
The team measured overall survival (OS) as the main end point, while cause-specific survival (CSS) and disease-free survival were secondary end points.
They used the Kaplan-Meier method to estimate the outcome measures.
|Survival increased as more nodes were analyzed.|
|Journal of Clinical Oncology|
In addition, the investigators compared results using a log-rank test, and Cox proportional hazards regression was used identify predictors of outcome.
The researchers found that the median number of lymph nodes removed at colectomy was 11.
The team determined that 648 patients had no evidence of lymph node metastasis.
They found that survival decreased with increasing number of lymph node involvement.
However, after controlling for the number of nodes involved, the team determined that survival increased as more nodes were analyzed.
Furthermore, even when no nodes were involved, OS and CSS improved as more lymph nodes were analyzed.
Dr Le Voyer's team concluded, "The number of lymph nodes analyzed for staging colon cancers is, itself, a prognostic variable on outcome".
"The impact of this variable is such that it may be an important variable to include in evaluating future trials".