Standardized probe-directed sentinel node dissection in melanoma

Background. Radiopharmaceutical agents appear to improve the accuracy of se ntinel node (SN) identification in patients,with early-stage melanoma, but the optimal radiopharmaceutical agent and its timing from injection to surg ery remain controversial. We undertook this investigation to examine the ut ility of 3 methods of intraoperative lymphatic mapping with radiopharmaceut ical-directed sentinel lymphadenectomy (LM/SL). We suspected that concurren t injection of radiopharmaceutical and blue-dye would lead to the greatest success of SN identification. Methods. The study was composed of 247 consecutive patients who had America n Joint Committee an Cancer stage I or II melanoma. Before LM/SL, all patie nts underwent cutaneous lymhoscintigraphy by I of 3 techniques: technetium 99m (Tc 99m) human serum albumin (HSA) injected at feast 24 hours before LM /SL (124 patients), Tc 99m filtered sulfur colloid (SC) injected no more th an 4 hours before LM/SL (same-day SC, 95 patients), or Te 99m SC injected a t least 18 hours before LM/SL (prior-day SC, 28 patients). At the time of L M/SL isosulfan blue dye was injected alone (SC groups) or with a second dos e of HSA (HSA group). A hand-held gamma probe was used to determine the rad ioactive (hot) counts of blue-stained and nonstained nodes, and the in vivo and ex vivo node-to-background count ratios of the nodes were compared. Results. Preoperative LS identified 299 drainage basins; LM/SL identified a t feast 1 SN in 119 (98 %) of 121 basins using same-day SC, 142 97 % of 146 basins using NSA, and 32 (100 %) of 32 basins using prior-day SC. There wa s no difference (P = .62) in the accuracy rate between the 3 techniques. Th e total number of SNs was 463. Same-day SC yielded higher intraoperative no de-to-background count ratios than did either of the other techniques (P < .0001). Same-day SC also had the greatest relative change in radioactivity between the blue sentinel node and the post-excision basin (P < .0001), and the highest rate of SNs that were both blue and hot (in vivo or ex vivo ra tio greater than or equal to 2, P = .05). Conclusions, LS and LM/SL performed on the same day with a single injection of filtered Tc 99m SC serves as the most useful method for probe-directed LM/SL. This technique demonstrated the highest in vivo and ex vivo count ra tios, fall-off of radioactivity between the excised nodes and post-excision basin, and concordance between blue dye and hot nodes. It should be recomm ended as the method of choice for probe-directed LM/SL.