Vital dye lymphatic mapping alone may suffice for inguinal sentinel lymph node biopsy

Patent blue dye (PBD) appears to be sufficient for inguinal sentinel lymph node biopsy in melanoma patients, said Luis Tovo, M.D., Ph.D. yesterday.

His statement was based on the results of a study evaluating 192 patients with localized cutaneous melanoma (Breslow thickness 0.76-mm) who were treated at the Oncology Prevention Center, Sao Paulo, by a multidisciplinary team. All patients underwent sentinel lymph node biopsy with preoperative lymphoscintigraphy, intraoperative lymphatic mapping with PBD according to the technique of Morton et al., and intraoperative gamma probe detection (GPD).

A total of 344 sentinel nodes were excised. Overall, GPD detected 97 percent of the sentinel nodes and PBD identified 93 percent. Analyzing the results with the nodes divided by basin showed GPD and PBD were complementary to each other in the axillary and cervical basins, although for both sites, the detection rate was higher for GPD than for PBD (axillary basin: 95 vs. 84 percent; cervical basin 93 vs. 91 percent). However, both techniques detected 100 percent of the 148 nodes excised from inguinal basins.

"Further investigations are needed to confirm our results and we must also consider that there is a learning curve for optimizing the PBD technique. However, our study suggests that if the surgeon is skilled, then PBD alone could be used for inguinal sentinel lymph node biopsy, and that would make the procedure less costly and more accessible," Dr. Tovo says.