e15000 Introduction: Sentinel Lymph Node Mapping (SLNM) in colon cancer (CCa) is shown to be successful, sensitive and accurate. We aimed to evaluate the survival of patients (pts) undergoing SLNM in addition to the standard colon resection, compare it to pts without SLNM and correlate it to the number of LN metastasis. Methods: Staging and survival analysis from our prospective database (gpA, 195 pts) were compared to the Surveillance, Epidemiology, and End Results (SEER) database (gpB, 126,484 pts) between 1996–2003. All pts had invasive CCa. GpA pts underwent SLNM plus complete resection. The minimum follow up (F/U) was 5 years. The primary outcome was cancer-specific survival. Exclusion criteria were stage IV disease, 2nd malignancy, or lost to F/U. Cancer specific survival of gpA was then analyzed according to the number of positive LNs. Results: In gpA (195 pts), SLNM was successful in 99.7%, of pts with a sensitivity, negative (-ve) predictive value, and false -ve rates of 86.3%, 91.7% and 14.6% respectively. In 15.1% of node +ve pts, the disease was upstaged because of micrometastasis (0.2–2mm). In gpA, 128 pts were included, of which 17(13.3%) lost to F/U as compared to 89,483 pts included in gpB, of which 47,168 (52.7%) lost to F/U. The average number of LNs examined per pt was 15 in gpA as compared to 12.4 in gpB (p=<0.0001). The 5 year-cancer specific survival of pts in gpA vs gpB was 100% vs 94.9% in stage I, 91.2% vs 83.5% in stage II and 81.8% vs 63% in stage III disease. For gpA pts, the 5 year cancer-specific survival decreased from 95.0% in node -ve disease to 92.8% when 1 LN was +ve, 83.3% when 2 LNs were +ve and 71.4% when 3 or more LNs were +ve (Table). Conclusions: A significant number of pts with CCa are being upstaged and the true node -ve disease is being identified when SLNM is performed at the time of surgery leading to improved survival as compared to conventional surgery. Our study showed that the number of LN metastasis is a predictor of cancer specific survival even after SLNM in CCa. [Table: see text] No significant financial relationships to disclose.