Accuracy of lymphatic mapping and sentinel lymph node biopsy after previous wide local excision in patients with primary melanoma

BACKGROUND. Sentinel lymph node (SLN) status is the most important prognostic factor with respect to the survival of patients with primary cutaneous melanoma. However, lymphatic mapping and SLN biopsies (LM/SLNBs) performed in patients who have had a wide local excision (WLE) may not accurately reflect the pathologic status of the draining lymph node basins. The purpose of this study was to assess the feasibility and accuracy of LM/SLNB in patients who have had a previous WLE. METHODS. A single-institution database was examined to identify patients who had a WLE before LM/SLNB and patients who had a concomitant LM/SLNB. Primary clinicopathologic features (age, tumor thickness, and ulceration), SLN identification rate, SLN pathologic status, and the incidence and sites of recurrences were compared between patients with and without prior WLE. RESULTS. Of the 1395 patients identified, 104 had WLE before LM/SLNB. The mean preoperative WLE radial margin was 1.4 cm (median, 1.0 cm). LM/SLNB was successful in 103 of 104 (99%) patients. Age, tumor thickness, incidence of ulceration, and incidence of SLN positivity in the group with prior WLE were similar to those of the cohort of patients who had concomitant LM/SLNB and WLE (n = 1291). In 97 (93%) of the 104 prior-WLE patients, the surgical defects were closed by either primary closure or skin graft; 7 patients (7%) had rotational flaps. The median follow-up of these 104 patients was 51 months. Among the prior-WLE group, 19 patients (18%) had a positive SLNB; of these 19 patients, 4 (21%) had recurrences (3 distant failures and 1 local and distant failure). There were no lymph node recurrences - in a mapped or unmapped basin - in these 104 patients with a negative or positive SLNB. CONCLUSIONS. SLNs can be successfully identified and accurately reflect the status of the regional lymph node basin in carefully selected melanoma patients with a previous WLE. Prior WLE does not appear to adversely impact the ability to detect lymphatic metastases, although the utility of LM/SLNB in patients who have undergone extensive reconstruction of the primary excision site remains to be defined. Because more extensive surgery may be required to accomplish accurate lymph node staging in patients who have undergone prior WLE - including the possible removal of SLNs from additional lymph node basins and an additional surgical procedure - to minimize morbidity and cost, concomitant WLE and LM/SLNB is strongly preferred whenever possible.