Management of sentinel lymph nodes in lower extremity melanoma with dual-basin (inguinal and popliteal) drainage on lymphoscintigraphy

ABSTRACT

PURPOSE: To analyze clinical outcomes of sentinel lymph node (SLN) biopsy in lower extremity melanoma with dual-basin drainage on lymphoscintigraphy.METHODS: We retrospectively analyzed patients with lower extremity melanoma who underwent lymphoscintigraphy and SLN biopsy in a single center between 2006 and 2015. Gamma probe was used to detect SLNs. For dual-basin drainage, we regarded a basin that showed a two-fold greater radioactivity value than the others as a ‘dominant’ basin. SLN biopsy was performed only for the dominant basin. If two basins showed similar radioactivity, biopsy was conducted for both.RESULTS: One hundred and seven patients underwent preoperative lymphoscintigraphy, and 29 dual (popliteal, inguinal) drainages were found. Of the 29 melanomas with dual drainage, seven showed similar radioactivity on both basins, 22 showed inguinal as the dominant basin and no melanoma had a dominant popliteal basin. Among the seven patients who underwent dual-basin biopsy, six had negative results, all of which experienced no recurrence during follow-up. Among the 22 patients who underwent biopsy of the dominant inguinal basin, 19 had negative results. During the follow-up, these patients showed six recurrences, but none of them experienced popliteal recurrence. All three patients who had tumor-positive inguinal node experienced recurrence in the popliteal basin as well as at other sites.CONCLUSION: For melanomas showing dual-basin drainage on lymphoscintigraphy, performing SLN biopsy only on the dominant (inguinal) basin is reliable when the dominant basin shows negative results. However, considering the recurrence pattern of our data, a tumor-positive dominant basin should prompts an SLN biopsy of the other basin.