In colorectal resections, to use the number of metastatic lymph nodes as a reliable tumor staging criterion, the total number of dissected lymph nodes must be above a certain threshold. However, it is difficult to reach required number after neoadjuvant treatment. In this study, we especially evaluated the factors which may affect the number of dissected lymph nodes from rectum resections received neoadjuvant therapy. One hundred two rectum resections were reviewed. The relation with the number of dissected lymph nodes and some criteria of patient and tumor were evaluated. The number of dissected lymph nodes was greater in high grade tumors from younger patients showing mucinous component, perineural invasion, positive radial surgical margin, and with metastatic lymph node. Inadequate tumor regression, extramural tumor depth, and being resected in recent years were also correlated with increased number of dissected lymph nodes. We noticed that the diameter of the largest lymph node has an impact on the total number of lymph nodes. Among these criteria, the patient’s age, tumor depth and the diameter of the largest dissected lymph node were most statistically significant. We evaluated the rectum resections after neoadjuvant therapy as a unique model and discussed the factors should be considered while dissecting the lymph nodes.
Keywords: Rectum tumor, lymph node dissection.
