Validation of the accuracy of intraoperative lymphatic mapping and sentinel lymphadenectomy for early-stage melanoma - A multicenter trial

Objective To evaluate the multicenter application of intraoperative lymphat ic mapping, sentinel lymphadenectomy, and selective complete lymph node dis section (LM/SL/SCLND) for the management of early-stage melanoma. Summary Background Data The multidisciplinary technique of LM/SL/SCLND has been widely adopted, but not validated in a multicenter trial. The authors began the international Multicenter Selective Lymphadenectomy Trial (MSLT) 5 years ago to evaluate the survival of patients with early-stage primary m elanoma after wide excision alone versus wide excision plus LM/SL/SCLND. Th is study examined the accuracy of LM/SL/SCLND in the MSLT, using the experi ence of the organizing center (John Wayne Cancer institute [JWCI]) as a sta ndard for comparison. Methods Before entering patients into the randomization phase, each center in the MSLT was required to finish a 30-case learning phase with complete n uclear medicine, pathology, and surgical review. Selection of MSLT patients in the LM/SL/SCLND treatment arm was based on complete pathologic and surg ical data. The comparison group of JWCI patients was selected using these c riteria: primary cutaneous melanoma having a thickness greater than or equa l to 1 mm with a Clark level greater than or equal to III, or a thickness < 1 mm with a Clark level greater than or equal to IV (MSLT criterion); LM/SL performed between June 1, 1985, and December 30, 1998; and patient not ent ered in the MSLT. The accuracy of LM/SL/SCLND was determined by comparing t he rates of sentinel node (SN) identification and the incidence of SN metas tases in the MSLT and JWCI groups. Results There were 551 patients in the MSLT group and 584 patients in the J WCI group. in both groups, LM performed with blue dye plus a radiocolloid w as more successful (99.1%) than LM performed with blue dye alone (95.2%) (p = 0.014). After a center had completed the 30-case learning phase, the suc cess of SN identification in the MSLT group was independent of the center's case volume or experience in the MSLT. Conclusions Lymphatic mapping and sentinel lymphadenectomy can be successfu lly learned and applied in a standardized fashion with high accuracy by cen ters worldwide. Successful SN identification rates of 97% can be achieved, and the incidence of nodal metastases approaches that of the organizing cen ter. A multidisciplinary approach (surgery, nuclear medicine, and pathology ) and a learning phase of greater than or equal to 30 consecutive cases per center are sufficient for mastery of LM/SL in cutaneous melanoma, lymphati c mapping performed using blue dye plus radiocolloid is superior to LM usin g blue dye alone.