Colorectal Specialization Increases Lymph Node Yield: Evidence from a National Database

Background: Current guidelines recommend the evaluation of at least 12 lymph nodes (LNs) in the pathologic specimen following surgery for colorectal cancer (CRC). We sought to examine the role of colorectal specialization on nodal identification. Methods: We conducted a retrospective cohort study using SEER-Medicare data to examine the association between colorectal specialization and LN identification following surgery for colon and rectal adenocarcinoma between 2001 and 2009. Our dataset included patients >65 years who underwent surgical resection for CRC. We excluded patients with rectal cancer who had received neoadjuvant therapy. The primary outcome measure was the number of LNs identified in the pathologic specimen following surgery for CRC. Multivariate analysis was used to identify the association between surgical specialization and LN identification in the pathologic specimen. Results: In multivariate analysis, odds of an adequate lymphadenectomy following surgery with a colorectal specialist were 1.32 and 1.41 times greater for colon and rectal cancer, respectively, than following surgery by a general surgeon (p < 0.001). These odds increased to 1.36 and 1.58, respectively, when analysis was limited to board-certified colorectal surgeons. Hospital factors associated with ≥12 LNs identified included high-volume CRC surgery (colon OR 1.84, p < 0.001; rectal OR 1.78, p < 0.001) and NCI-designated Cancer Centers (colon OR 1.75, p < 0.001; rectal OR 1.64; p = 0.007). Conclusions: Colorectal specialization and, in particular, board-certification in colorectal surgery, is significantly associated with increased LN identification following surgery for colon and rectal adenocarcinoma since the adoption of the 12-LN guideline in 2001.