Number of retrieved lymph nodes and survival in node-negative patients undergoing laparoscopic colorectal surgery for cancer.

Background: The number of retrieved lymph nodes in colorectal cancer resection may have an impact on staging and survival. Examination of at least 12 nodes has become a quality measure for adequate surgical practice. To evaluate the impact of the number of retrieved lymph nodes in laparoscopic colorectal surgery for cancer on node-negative patients' survival.

Methods: Evaluation of our prospective in-hospital collected data of patients that underwent laparoscopic surgery for curable colorectal cancer over a 5-year period. Long-term data were collected from our outpatient's clinic data and personal contact when necessary.

Results: During a 5-year period since September 2003,173 patients were operated laparoscopically for curable colorectal cancer. Of the 117 patients who were node negative, 85 node-negative patients (72%) had 12 or more evaluated lymph nodes (mean, 18.3 + 2.4), while 32 node-negative patients had less than 12 (mean, 8.3 + 6.2). Patients with fewer than 12 nodes evaluated had significantly more left-sided tumors, while patients with 12 nodes or more had more right-sided tumors. A comparison of 5-year disease free and overall Kaplan-Meier survival curves revealed no statistically significant difference between the two groups.

Conclusions: Evaluation of less than 12 nodes may not necessarily impact patients' survival in node-negative patients undergoing laparoscopic resection for curable colorectal cancer. A lower number of nodes may be sufficient.