Risk factors for sentinel lymph node metastasis in Korean acral and non-acral melanoma patients

Breslow thickness, ulceration, and mitotic rate are well-known prognostic factors for sentinel lymph node (SLN) metastasis in cutaneous melanoma. We investigated risk factors, including especially the degree of pigmentation, for SLN metastasis in Korean melanoma patients. We enrolled 158, composed of Korean 107 acral and 51 non-acral melanoma patients who underwent SLN biopsy. Clinicopathologic features such as Breslow thickness, ulceration, mitotic rate, and the degree of pigmentation were evaluated. The recurrence-free survival (RFS) rate and date of recurrence were determined. Fifty-four patients (34.2%) had a positive SLN biopsy result. In a multivariate analysis, Breslow thickness (odds ratio [OR] 1.93; 95% confidence interval [CI], 1.12–3.47; p = .022) and heavy pigmentation (OR 13.14; 95% CI, 2.96–95.20, p = .002) were associated with SLN metastasis. Positive SLN patients had a higher rate of loco-regional and/or distant recurrence (hazard ratio 6.32; 95% CI, 3.39–11.79; p < .001). Heavy pigmentation was associated with poor RFS. Heavy pigmentation is an independent predictor of SLN metastasis in both acral and non-acral melanoma. Our results suggest the need for in-depth SLN evaluation of cutaneous melanoma patients with heavy pigmentation and provide clinicians with important information for determining patient prognosis.