537 Background: As the interest in local excision (LE) for rectal cancer increases, the risk of residual nodal disease and local failure must be considered. We utilized a nationwide cancer registry to establish incidence and predictors of nodal metastasis in early pathologic T stage rectal cancers. Methods: Early path T stage rectal cancers (1998-2007) were identified from the National Cancer Database (NCDB), including pT1-2 tumors in patients not receiving neoadjuvant therapy (NT), or ypT0-2 tumors after NT. Proctectomy was performed in 22,416 (74.7%) and LE in 7,589 (25.3%) without NT. After NT, 7,481 (96.1%) underwent proctectomy and 300 (3.9%) LE. Nodal metastasis rates were calculated from proctectomy patients. Factors associated with nodal metastases were analyzed among those with ≥12 nodes assessed. Results: The incidence of nodal positivity was 12.5% for pT1 and 26.8% for pT2 tumors. Among those with ≥12 nodes examined, these rates increased to 16.9% and 28.6% respectively. After receiving NT, nodal positivity rates were 8.6% for ypT0, 12.9% for ypT1, and 21.4% for ypT2 tumors. These rates increased to 13.5%, 16.9% and 28.3% respectively when ≥12 nodes examined. In multivariate analysis, female sex, age <50, higher T stage, higher histologic grade, mucinous/signet-ring features, and more than 12 nodes examined were all significantly associated with nodal metastases in both groups ( Table ). Conclusions: Among rectal cancers of early path T stages, the risk of nodal metastasis increases with higher path T stage and with greater number of nodes examined, regardless of receipt of NT. These findings must be carefully deliberated, given the current interests in expanding the role of LE based on pathologic T stage of rectal cancer. [Table: see text]
Role of local excision in the management of rectal cancer: what does the future hold?