The Role of Sentinel Lymph Node Biopsy in Patients with Local Recurrence or In-transit Metastasis of Melanoma

From January 2003 to March 2010, a prospective study was undertaken at the National Cancer Research Institute of Genoa in 15 patients with melanoma who had local recurrence (LR) or a few (≤ 3) in-transit metastases and clinically-negative regional lymph nodes with the aim of defining: i) the feasibility of sentinel node re-staging (r-sN) of the regional nodal basin; ii) the prognostic value of sentinel node status, and iii) the potential benefit in terms of disease-free survival and overall survival in patients with an histologically-positive sentinel node undergoing therapeutic regional lymph node dissection. Preoperative lymphoscintigraphy was performed to identify the r-sN: the radiotracer was intra-dermally injected around the LR or in-transit metastasis. Moreover, 10 min prior to the operative procedure, 0.5 ml intradermal injection of Patent-Blue-V dye was given around each LR or in-transit metastasis site, so that r-sN identification was achieved by both visualization of the nodal blue dye staining and the information supplied by gamma-detection probe. At least one sentinel node was intra-operatively identified in each patient, and a tumor-positive r-sN was required in four out of fifteen patients. The interval between the diagnosis of primary melanoma and the onset of recurrence was longer, although not significantly, in patients with tumor-negative r-sN, a compared to tumor-positive r-sN (49 ± 47 months vs. 25 ± 19 months, p=0.342). There was a trend toward an improved 1-, 3-, and 5-year disease-free survival and overall survival in patients with tumor-negative r-sN a compared to tumor-positive r-sN. Hence, the r-sN proved to be a feasible and accurate staging procedure even in patients with a few localizations of LR or in-transit metastases (≤ 3). r-sN identified those with a more favorable prognosis, supporting an aggressive therapeutic approach in the natural history of their disease; moreover, an unnecessary regional lymph node dissection was safely avoided in 11 out of 15 73.3% patients because they had a tumor-negative r-sN.