Increased lymph node harvest in patients operated on for right-sided colon cancer: a population-based study

In recent decades, the focus has been on the treatment of rectal cancer with improved surgical techniques. This has resulted in improved results for patients with rectal cancer. Recently, the focus has shifted to colon cancer surgery with the introduction of preoperative staging, new surgical techniques, quality control and enhanced recovery programmes. The change in operative techniques has been most pronounced for patients with tumours on the right side of the colon, with more extensive resections and proximal ligations of the vessels. The aim of this study was to assess the number of analysed lymph nodes and the metastatic index (MI) in patients operated on for right-sided colon cancer in the Stockholm area between 1996 and 2009.

All patients operated on for cancer of the right colon between January 1996 and December 2009 were divided into three groups based on the year in which they were operated (period 1, 1996-1999; period 2, 2000-2004; and period 3, 2005-2009). The number of lymph nodes and lymph node status were analysed.

In total, 3536 patients were operated on for right-sided colon cancer during the study period. There was a significantly lower proportion of emergency operations in the third time period. The mean number of lymph nodes examined increased significantly during the overall study period (seven in period 1, 11 in period 2 and 18 in period 3; P < 0.001). A significant drop in MI was seen during the third time period (0.25, compared with 0.40 in period 1 and 0.40 in period 2; P < 0.001).

During the study period there was an increase in the number of analysed lymph nodes and a decrease in MI after right-sided hemicolectomies. Further investigations are needed to evaluate the potential impact on short-term and long-term outcome.