Prediction of Sentinel Lymph Node Positivity by Growth Rate of Cutaneous Melanoma

OBJECTIVE: To determine whether growth rate (GR) of cutaneous melanoma predicts the histological sentinel lymph node (SLN) positivity. DESIGN: Retrospective cohort study. SETTING: Two tertiary melanoma referral centers. PATIENTS: A total of 698 patients with invasive primary cutaneous melanoma in whom the SLN was identified between January 1, 2000, and June 30, 2010. MAIN OUTCOME MEASURE: Based on previous studies, a surrogate measure for GR in primary invasive melanoma was calculated as the ratio of Breslow thickness to time to melanoma development. RESULTS: The SLN was positive in 20.2% of patients. Multivariate logistic regression analysis revealed that GR, Breslow thickness, and the presence of microscopic satellitosis were independently associated with SLN positivity. The probability of SLN positivity was 8.2% for slow-growth melanomas (<0.10 mm/mo) compared with 19.8% for intermediate-growth melanomas (0.10-0.50 mm/mo) and 37.7% for fast-growth melanomas (>0.50 mm/mo). Growth rate was not an independent predictive factor for survival. CONCLUSION: Growth rate of primary cutaneous melanoma, together with Breslow thickness and the presence of microscopic satellitosis, predicts the histological SLN positivity.