Regression does not predict nodal metastasis or survival in patients with cutaneous melanoma

Controversy exists regarding the prognostic implications of regression in patients with cutaneous melanoma. Some consider regression to be an indication for sentinel lymph node (SLN) biopsy because regression may result in underestimation of the true Breslow thickness. Other data support regression as a favorable prognostic indicator, representing immune systemrecognition of the primary tumor. This analysis was performed to determine whether regression predicts nodal metastasis, disease-free survival (DFS), or overall survival (OS). Post hoc analysis was performed of a multicenter prospective randomized trial that included patients aged 18 to 70 years with cutaneous melanomas 1 mm or greater Breslow thickness. All patients underwent SLN biopsy; those with tumor-positive SLN underwent completion lymphadenectomy. Kaplan-Meier analysis of survival, univariate analysis, and multivariate analysis were performed. A total of 2220 patients (261 with regression; 1959 without regression) were included in this analysis with a median followup of 68 months. Patients with regression were more likely to be male, older than 50 years old, and have lower median Breslow thickness, superficial spreading histologic subtype, and a nonextremity anatomic location (P < 0.05 in all cases). Regression was not significantly associated with Clark level, ulceration, lymphovascular invasion, number of SLNs removed, or SLN metastasis. On multivariate analysis, factors independently predictive of DFS included Breslow thickness, ulceration, and SLN status (P < 0.05 in all cases); the same factors along with age, gender, and anatomic tumor location were significantly associated with OS (P<0.05 in all cases). Regression was not significantly associated with DFS (risk ratio [RR], 0.94; 95% confidence interval [CI], 0.67-1.27; P = 0.68) or OS (RR, 1.01; 95% CI, 0.76-1.32; P = 0.93). These data suggest that regression is not a significant prognostic factor for patients with cutaneous melanoma and should not be used to guide clinical decision-making for such patients.