Accurate identification and evaluation of regional lymph nodes is necessary to properly stage cancer patients, which in turn provides prognostic information, and allows selection of appropriate additional therapy.
Sentinel lymph node (SLN) mapping represents a paradigm shift in nodal evaluation. As the first nodes draining a solid tumor, identification and focused evaluation of the SLNs provides more accurate staging compared to conventional methods. Based on SLN status, extended lymph-adenectomy in cases of melanoma or breast cancer may be avoided. In the gastrointestinal (GI) tract, where regional nodes are still harvested as part of standard oncologic resection, SLN mapping provides more accurate nodal staging, and may identify aberrant drainage pathways to assure that the proper nodes are excised.
Topics to be addressed in this discussion will include: (1) advantages of SLN mapping in GI cancers with discussion of pathologic protocols and evaluation; (2) comparative focused evaluation of SLNs and non-SLNs; (3) evaluation of non-tumor associated SLN; (4) comparative studies of node sizes between SLNs and non-SLNs; (5) current lines of research and future directions.