Variables Impacting Lymph Node Assessment in Colorectal Resection Specimens Removed for Adenocarcinoma
O Tawfik, BF Kimler, DH McGregor, F Fan. Kansas University Medical Center, Kansas, KS; Radiation Oncology; Kansas City VA Medical Center, Kansas, MO
Background: Recent data suggest that higher number of nodes evaluated in colon cancer colectomy specimens is associated with better survival, regardless of pathologic findings. Recommendations from the American College of Surgeons, the American Society of Clinical Oncology and others mandate the harvesting of at least 12 nodes in colectomy specimens for adequate assessment. Number of nodes harvested is not only being used as a benchmark for both surgeons and pathologists but is also proposed to be of significance for payment strategies to surgeons and institutions by insurance companies. Recent published studies contradict this concept and argue that the above association is complex and is uncontrolled for a variety of confounding variables. The objective of this study is to evaluate the impact of several key confounding factors on our ability to harvest at least 12 nodes per colectomy specimen.
Design: We reviewed 306 colon cancer colectomy specimens from 2 academic medical centers, including 177 from Kansas University Medical Center (KUMC) and 129 from The Kansas City Veterans Affairs Medical Center (VAMC) from 2003 to 2007. Factors evaluated included tumor size, grade, stage, site, number of positive nodes and length of colectomy segment removed. In addition we compared the number of nodes removed in the 2 sites and whether individual surgeons had an impact on number of harvested nodes.
Results: The likelihood of harvesting >12 nodes is correlated with larger tumor size, higher grade and stage and specimens longer than 21 cm. More nodes were harvested from the right colon (mean=13 nodes), followed by descending (12 nodes), transverse and rectosigmoid (10 nodes, each). Surgery date didn't have an impact on number of harvested nodes. Number of positive nodes correlated with tumor grade, but not with tumor site, size, linear length of specimen or 12 nodes or more harvested. More cases from the VAMC were likely to harvest at least 12 nodes compared to KUMC. That was not related to tumor size, grade, stage, tumor site or length of segment removed. It was noted however, that 2 of 10 surgeons at the VAMC performed 76% of cases. There were 21 surgeons at KUMC; none performed more than 12% of the cases.
Conclusions: Number of harvested nodes is primarily influenced by prognostically significant parameters mainly related to tumor biology. The potential impact of surgeon's experience and the type of surgery performed needs further evaluation.
Tuesday, March 10, 2009 8:15 AM
Platform Session: Section C, Tuesday Morning