MINIMALLY INVASIVE STAGING OF PATIENTS WITH MELANOMA - SENTINEL LYMPHADENECTOMY AND DETECTION OF THE MELANOMA-SPECIFIC PROTEINS MART-1 AND TYROSINASE BY REVERSE-TRANSCRIPTASE POLYMERASE-CHAIN-REACTION

Background: A minimally invasive standard has yet to be developed for sentinel lymphadenectomy, and many patients undergo this procedure in the main operating room under general anesthesia. These patients often have microscopic metastases in sentinel nodes that could be missed by histopathologic examination. Techniques of reverse transcriptase poly merase chain reaction (RT-PCR) could detect these metastases if the no des could be preserved intraoperatively. Study Design: Fifty patients with melanoma greater than or equal to 1 mm thick underwent sentinel l ymphadenectomy under local anesthesia in an outpatient surgical unit. Sentinel nodes were identified using blue dye and technetium-99 sulfur colloid and a hand-held gamma probe. Each node was sectioned, with ha lf sent for routine histopathologic study and half preserved in liquid nitrogen. We used RT-PCR to detect mRNA for tyrosinase and Melanoma A ntigen Recognized by T cells-1 (MART-1). Results: Ad patients were abl e to tolerate sentinel lymph node biopsy under local anesthesia. Senti nel lymph nodes were obtained in 100% of our patients, and usable mRNA was harvested from all but five. Ten patients had positive sentinel n ode(s) by standard histopathologic examination, and all of these nodes were also positive for MART-1 and tyrosinase. Three patients with neg ative results by histopathology had positive results by RT-PCR analysi s. The average cost of these outpatient operations was 38% less than t he same operations performed in the main operating room under general anesthesia. Conclusions: Sentinel lymphadenectomy under local anesthes ia in an outpatient setting and intraoperative lymph node preservation in liquid nitrogen are both feasible. Both tyrosinase and MART-1 are promising markers in the detection of occult melanoma in lymph nodes. (J Am Coll Surg 1998;187:182-190. (C) 1998 by the American College of Surgeons)