Multivariate prognostic model for patients with thick cutaneous melanoma: importance of sentinel lymph node status.

BACKGROUND: The overall prognosis of patients with thick cutaneous melanoma (TCM) is generally thought to be poor. Surgically staging these patients with sentinel lymph node (SLN) biopsy remains controversial. This study was performed to determine whether SLN status improved our ability to predict outcome over other known prognostic factors and to develop a model incorporating independent prognostic factors to estimate the risk of recurrence for an individual patient.

METHODS: A prospective database identified patients with TCM (>4.0 mm or Clark level V) and clinically negative nodes who underwent SLN biopsy. Univariate and multivariate analyses were performed.

RESULTS: From 1991 to 2001, 126 patients were identified; 75 (60%) were male. The median age was 60 years. The median tumor thickness was 5.5 mm, and 43% were ulcerated. Thirty percent of patients had a positive SLN. Recurrence was seen in 50 patients (40%). Median follow-up, relapse-free survival, and overall survival were 25, 50, and 68 months, respectively. Factors independently predictive of recurrence were age >/=60 years, depth >5.5 mm, ulceration, and SLN positivity. SLN status was the most significant prognostic factor (P <.001). The relative risk of recurrence for an individual patient ranged from 1 in patients for whom no adverse factors were present to 29.4 when all factors were present.

CONCLUSIONS: SLN status was the strongest independent predictor of outcome in patients with TCM. However, patients with TCM are prognostically heterogeneous, and all independently predictive factors should be considered when an individual patient's risk of recurrence is assessed.