Lymphatic mapping and focused analysis of sentinel lymph nodes upstage gastrointestinal neoplasms

Background: Lymph node analysis is essential for staging gastrointestinal ( GI) neoplasms. Intraoperative lymphatic mapping and sentinel lymphadenectom y were originally described for melanoma but have not yet been investigated for most GI neoplasms. Hypotheses: (1) Lymphatic mapping and sentinel lymphadenectomy is feasible in GI neoplasms, (2) the sentinel node (SN) status reflects the regional no de status, and (3) focused analysis of the SN improves staging accuracy. Design: Prospective patient series. Patients and Methods: Lymphatic mapping was performed in 65 patients with G I neoplasms by injecting 0.5 to 1 mL of isosulfan blue dye around the perip hery of the neoplasm. Blue-stained SNs were analyzed by hematoxylin-eosin s taining, multiple sectioning, and cytokeratin immunohistochemistry. Results: Lymphatic mapping identified at least 1 SN in 62 patients (95%). O f the 36 cases with nodal metastasis, 32 (89%) had at least 1 positive SN a nd 15 (42%) had nodal metastasis only in the SN. In II cases, tumor deposit s were identified by multiple sectioning (n=2) or immunohistochemistry (n=9 ) only. In 5 cases (8%), lymphatic mapping identified aberrant lymphatic dr ainage that altered the extent of the lymphadenectomy. Conclusions: Lymphatic mapping and sentinel lymphadenectomy are feasible in GI neoplasms and identify aberrant lymphatic drainage. The SN status accur ately reflects the regional node status. Focused analysis of the SN increas es the detection of micrometastases and may improve selection of patients f or adjuvant treatment.