Lymph Node Recovery From Colorectal Resection Specimens Removed for Adenocarcinoma:<i>Trends Over Time and a Recommendation for a Minimum Number of Lymph Nodes to be Recovered</i>

Recovery of pericolorectal lymph nodes from colectomy specimens has long been part of colorectal cancer staging. Recently, adjuvant therapy has been added for high stage carcinomas, providing further impetus for performing careful lymph node dissections. Pericolorectal lymph nodes were examined to determine if there has been a change over time in the number of lymph nodes recovered and proportion of specimens with pericolonic lymph node metastases from colorectal carcinoma resection specimens. Also, the authors attempted to establish a recommendation for a minimum number of lymph nodes that should be recovered before a colon can be considered free of metastases. Slides and reports of the first 20 consecutive pT3 colorectal carcinoma resections in each year from 1955 to 1995 at William Beaumont Hospital that did not have known metastases at the time of surgery were reviewed (750 specimens total). The mean number of lymph nodes recovered per specimen and incidence of detected lymph node metastases increased over the 41-year period, with the greatest increase occurring during 1992-1995. The greatest proportion of patients with lymph node metastases detected occurred in the 17 to 20 lymph nodes recovered per specimen group. Specimens with more than 20 lymph nodes did not have a higher proportion of lymph node metastases detected compared to specimens with 17 to 20 lymph nodes. Approximately 20% of the specimens with metastases had more than 17 lymph nodes recovered. These results suggest that pathologists should retrieve all the lymph nodes that can be recovered, but at least 17 lymph nodes should be recovered to insure accurate documentation of nodal metastases when present.