Comparative analysis of survival in colon cancer undergoing sentinel lymph node mapping vs conventional surgery based on number of positive lymph nodes.

Abstract

e15154 Background: Unlike in breast cancer or melanoma, resection during sentinel lymph node mapping (SLNM) in colon cancer (CCa) includes regional lymphadenectomy including SLNs and non-SLNs. However, SLNM often identifies micrometastases that can be missed by conventional (Conv) surgery and pathologic examination. It is unknown whether this impacts survival or recurrence. Hence, a retrospective analysis was undertaken to study overall (OS) and disease -specific (DSS) survival between patients (pts) undergoing SLNM vs Conv surgery based on the number of +ve LNs. Methods: SLNM was done by subserosal injection with blue dye followed by segmental resection including regional lymphadenectomy. All SLNs were ultrastaged and other nodes were examined by conv. methods with H&E. Results: There were 309 pts in SLNM (GpA) vs 499 pts in Conv surgery (GpB); with average no. of lymph nodes (LNs) and +ve LNs 17.3/1.6 vs 14.4/2.49 respectively. For GpA, success rate was 99.6% and the average no of SLN was 3. Of the pts in GpA vs GpB, 1+ve LN were found in 38% vs 27%, 2+ve LNs in 10% vs 16%, and > 2 LNs in 53% vs 57%, respectively. Comparing 5 years OS between GpA vs GpB, for 1+ve LN was 62.8% vs 52.38%, for 2 +ve LNs 72.7% vs 48.65% and for > 2 +ve LNs 35% vs 33.33%, respectively. Similarly, DSS for 1 +veLN was 54.4% vs 47.6%, 2+ve LNs 40% vs 40.54% and > 2+ve LNs, 30.4% vs 25.76%, respectively (Table). Conclusions: Compared to Conv surgery, SLNM identified higher no. of LNs per pt with high success rate. Five-year OS and DSS also are better in SLNM vs Conv surgery for all +ve LN gps. Hence, SLNM in CCa may have prognostic value. A larger multicenter trial needs to be done to validate such data. [Table: see text]