IMPROVED SENTINEL LYMPH-NODE LOCALIZATION IN PATIENTS WITH PRIMARY MELANOMA WITH THE USE OF RADIOLABELED COLLOID

Background, The purpose of this study was to determine whether the sen tinel lymph node (SLN) localization technique, which uses blue dye and Tc-99m-labeled sulfur colloid, provides advantages over blue dye alon e in the management of patients with stages I and II cutaneous melanom a. Methods. The records of 626 consecutive patients with melanoma who underwent lymphatic mapping and SLN biopsy between 1991 and 1997 at th e M.D. Anderson Cancer Center were reviewed. Lymphatic mapping was per formed with isosulfan blue dye alone (n = 252) or in combination with (99)mTc-labeled sulfur colloid accompanied by a hand-held gamma probe (n = 374). SLNs were defined as those that stained blue or demonstrate d increased focal radiotracer uptake. Results. SLN identification rate s improved from 87% (dye alone) to 99% (dye and colloid) (P < .0001) w ith the combined technique in all anatomic sites examined. The mean nu mber of SLNs harvested from each basin was significantly greater in th e patients mapped with dye and colloid (1.74 vs 1.31; P < .0001). Occu lt metastatic disease was identified in 17.5% of all patients and did not significantly differ between groups. In 92% of patients who had at least one positive SLN and were mapped with both agents, lymphatic me tastases were identified in the SLN that contained the greatest radiot racer uptake. In 19% of cases the first blue SLN harvested did not con tain the greatest radiotracer uptake. Conclusions. SLN identification is enhanced by the addition of radiolabebd sulfur colloid and intraope rative use of the hand-held gamma probe and may identify SLNs missed b y the blue dye alone. These data support the combined use of radiolabe led sulfur colloid and blue dye in lymphatic mapping procedures to imp rove the nodal staging of stages I and II melanoma.