This provides the basis of TME technique, as sharp dissection along the mesorectal fascia yields the entire mesorectum, which is the lymph node-bearing mesentery of the rectum. Secondarily, it removes any small regional metastases. Removing lymph nodes with the surgical specimen removes cancer cells, but more importantly provides information about staging, prognosis, and guides treatment decisions. For example, the United States

Surveillance, Epidemiology and End Results (SEER) cancer registry Inhibitors,research,lifescience,medical database shows that for each T stage, 5-year overall and disease-free survival decreases with increasing LN involvement. The presence of lymph node metastases determines the patients most likely to benefit from adjuvant therapy (2). The American Joint Committee on Cancer (AJCC) and the International Union Against Cancer (IUAC) Inhibitors,research,lifescience,medical recommends removing at least 12 lymph nodes to properly assess the adequacy of surgical resection and provide adequate information for staging. Having a Metabolism inhibitor minimal lymph node cut off value is problematic as the number of lymph nodes is highly individual, varying with age, location, and tumor characteristics such as growth Inhibitors,research,lifescience,medical factors and microsatellite instability. Even with standardized surgical technique and pathologic evaluation (including the use

of fat clearing to optimize lymph node harvest), the total number of lymph nodes harvested after neoadjuvant chemoradiation is highly variable and frequently less than 12, and with the possibility of fewer positive lymph nodes, downstaging can occur (3,4). To address this issue, we previously proposed calculating lymph node Inhibitors,research,lifescience,medical ratios as a method that incorporates the negative impact on survival of finding as few as one positive lymph node and the uncertainty Inhibitors,research,lifescience,medical regarding the optimal number of total lymph nodes to harvest (5). This lymph node ratio is valuable as an independent prognostic factor for overall survival, not only in rectal cancer,

but also in gastric, breast, bladder, pancreatic cancer, and colon cancer (6). medroxyprogesterone Interestingly, increasing the number of lymph nodes retrieved is associated with increased survival among patients with colorectal cancer (7,8). The article by Denham and colleagues in the current issue of the Journal of Gastrointestinal Oncology provides a wide-ranging review of multiple studies and biologic principles to determine the underlying basis of this observation. Given the lack of consensus in the literature, the authors conclude that the explanation for the association of increased survival with increased lymph node retrieval is multifactorial and lies in tumor-host biology (9). Clinically, deciding how many lymph nodes to retrieve is less relevant, as a surgeon performing a “cancer operation” should, by virtue of optimal surgical technique, maximize the mesenteric lymph nodes harvested.