Status of the regional nodal basin remains highly prognostic in melanoma patients with in-transit disease

Background The role of SLNB for in-transit (IT) melanoma is controversial. The objective of this study was to determine the rate and prognostic significance of occult nodal disease in patients undergoing surgical nodal staging for IT disease. Study Design We conducted a retrospective review of patients with IT melanoma from May 2005 through September 2014. Analysis was limited to patients with a first-time IT event who underwent surgical excision. Associations between clinicopathologic characteristics, patterns of recurrence, and survival were analyzed. Results A total of 261 patients treated at our center were identified and 157 met inclusion criteria, of which 135 (86%) presented with no evidence of nodal disease. At the time of surgical excision of the IT lesion, 80 (58%) clinically node-negative patients underwent observation of the nodal basin and 55 (41%) surgical nodal staging. Twenty (36%) clinically node-negative but surgically staged patients were found to have nodal disease. Distant metastasis-free survival was 70.8 months for surgically staged node-negative patients, 19.2 months for surgically staged node-positive patients, 22.8 months for those staged node-negative by clinical examination only and 4.8 months for those with clinical nodal disease (p = 0.01). The regional nodal basin was the first site of failure in 14 of 66 (21%) clinically staged patients, 5 of 50 (10%) for those surgically staged, and 6 of 16 (38%) for those with clinical nodal disease. Conclusions Patients with IT disease are at high risk for occult nodal metastasis. Because clinical staging is unreliable, SLNB should be considered. For patients with IT recurrence, the status of the regional basin is strongly prognostic and stratifies patients into low-, intermediate-, and high-risk groups.