A sentinel node biopsy does not increase the incidence of in-transit metastasis in patients with primary cutaneous melanoma

Background: It has been suggested that performing a sentinel node biopsy (SNB) in patients with cutaneous melanoma increases the incidence of in-transit metastasis (ITM). Methods: ITM rates for 2018 patients with primary melanomas >= 1.0 mm thick treated at a single institution between 1991 and 2000 according to 3 protocols were compared: wide local excision (WLE) only (n = 1035), WLE Plus SNB (n = 754), and WLE Plus elective lymph node dissection (n = 229). Results: The incidence of ITM for the three protocols was 4.9%, 3.6%, and 5.7%, respectively (not significant), and as a first site of recurrent disease the incidence was 2.5%, 2.4%, and 4.4%, respectively (not significant). The subset of patients who were node positive after SNB and after elective lymph node dissection also had similar ITM rates (10.8% and 7.1%, respectively; P = .11). On multivariate analysis, primary tumor thickness and patient age predicted ITM as a first recurrence, but type of treatment did not. Patients who underwent WLE only and who had a subsequent therapeutic lymph node dissection (n = 149) had an ITM rate of 24.2%, compared with 10.8% in patients with a tumor-positive sentinel node treated with immediate dissection (n = 102; P = .03). Conclusions: Performing an SNB in patients with melanoma treated by WLE does not increase the incidence of ITM.