Factors that influence 12 or more harvested lymph nodes in early-stage colorectal cancer.

BACKGROUND

The number of lymph nodes required for accurate staging is a critical component in early-stage (stage A and B) colorectal cancer (CRC). Current guidelines demand at least 12 lymph nodes to be retrieved. Results of previous studies were contradictory in factors, which influenced the number of harvested lymph nodes. This study was designed to determine the factors that influence the number of harvested lymph nodes (> or =12) in early-stage CRC in a single institution.

METHODS

Between 2003 and 2007, data on patients who underwent surgery for early-stage CRC were analyzed retrospectively. Data for a total of 470 patients were collected and all the tumor-bearing specimens were fixed with node identification performed. Several possible factors that influence 12 or more harvested lymph nodes were investigated and classified into four aspects: (1) operating surgeon, (2) examining pathologist, (3) patient (age, sex, and body mass index), and (4) disease (maximal length of tumor, length of specimen, tumor localization, tumor cell differentiation, Dukes stage, type of resection, and type of tumor).

RESULTS

A total of 289 patients (61.5%) with 12 or more harvested lymph nodes and 181 patients (38.5%) with < 12 lymph nodes were analyzed. The results demonstrate that within a single institution the maximal length of tumor, tumor localization, and depth of tumor invasion according to Dukes stage were independent influencing factors of 12 or more harvested lymph nodes. Maximal length of tumor was associated with more harvested lymph nodes (P < 0.001). Neither the operating surgeon nor the examining pathologist had significant influence on the number of harvested lymph nodes.

CONCLUSIONS

The number of harvested lymph nodes was highly variable in patients who underwent resection of early-stage CRC. Neither the operating surgeon nor the examining pathologist had significant influence on the number of harvested lymph nodes. Therefore, from the viewpoint of the surgeons, disease itself is the most important factor influencing the number of harvested lymph nodes.