Prediction of nonsentinel lymph node status in melanoma

Background: Most melanoma patients with a positive sentinel lymph node dissection (SLND) undergo a completion lymph node dissection (CLND) that does not yield additional positive nonsentinel lymph nodes (NSLN). This study was designed to determine if NSLN status can be predicted using patient, primary tumor, and sentinel lymph node (SLN) characteristics. Methods: The study population includes melanoma patients who had a positive SLND and subsequently underwent CLND retrieved from our prospective institutional melanoma database. The primary tumor and SLN pathologies were prospectively determined. An Size/Ulceration (SU) score was derived by assigning I point for primary tumor ulceration and 1 point for SLN tumor size >2 mm. Results: Ninety-eight patients had a positive SLND and underwent CLND. Sixteen of these patients had a positive NSLN. On univariate analysis, primary tumor characteristics (thickness, ulceration, no regression), SLN metastasis characteristics (size >2 mm, location nonsubcapsular), and SU score were all significantly associated with positive NSLN status. However, on multivariate analysis, only the SU score was a significant independent predictor of NSLN status. No patient with an SU score of 0 had a positive NSLN. Conclusions: The SU score is predictive of NSLN status in patients with a positive SLND. Patients with an SU score of 0 are very unlikely to have positive NSLNs at CLND.