ORLANDO – The inferior outcomes associated with right-sided colon cancers might be mitigated if a higher lymph node harvest is obtained, a retrospective study suggested.
“These data may provide indirect evidence for complete mesocolic excision to obtain a higher lymph node harvest to improve survival,” said investigator Arman Erkan, MD, of the Center for Colon and Rectal Surgery at Florida Hospital Orlando, in an oral abstract presentation.
This study adds new perspective on recent studies that have also demonstrated worse outcomes for right-sided versus left-sided tumors, which may be related to differences in levels of vascular ligation and nodal harvest. In addition, many studies to date have been limited in their ability to evaluate that hypothesis because of small sample size or other factors, he said in his presentation.
Accordingly, Dr. Erkan and his colleagues queried the National Cancer Database for colectomies for nonmetastatic colon adenocarcinoma occurring between 2004 and 2014, evaluating a total of 504,958 patient records, of which 273,198 were for right-sided tumors. To minimize bias, they used propensity score matching, leaving 148,540 patients in each group for the primary analysis.
Right-sided tumors were associated with inferior 5-year survival for patients with stage II and III disease (P less than .001 for right vs. left in both analyses), the investigators found.
In multivariate analysis, they found a significant interaction between right-sided tumors and a lymph node harvest of greater than 22 nodes toward increased survival, with a hazard ratio of 0.87 (95% confidence interval, 0.84-0.90). “This indicates that survival after right-sided resections can be improved if more than 22 nodes are harvested during the surgery,” Dr. Erkan said.
The difference was most pronounced in stage III of the disease, he added.
Study coauthor, a colorectal surgeon at McGill University, said in a related press release that the study findings might prompt surgeons to reevaluate the types of procedures they perform in patients with right-sided tumors. “These patients may need a more extensive resection than is considered to be standard for them.”
Dr. Erkan, Dr. Lee, and other coinvestigators reported no conflicts of interest related to their research.