Value of DNA ploidy and S-phase fraction as prognostic factors in stage III cutaneous melanoma

OBJECTIVE: To determine the prognostic value of flow cytometric analysis (S -phase fraction and DNA index) performed on lymph-node metastases of patien ts with stage III melanoma. DESIGN: A retrospective chart review with now cytometric analysis of paraff in-embedded tissues. SETTING: A university teaching hospital. PATIENTS: Among 332 patients with cutaneous melanoma, 33 with stage III wer e identified. Distant metastases developed in 16 patients; 17 had no furthe r recurrence. Charts were reviewed to obtain clinicopathologic parameters s uch as sex, age, location of the primary tumour, histologic features, prese nce or absence of ulceration, and Clark's and Breslow's levels. INTERVENTION: DNA ploidy and S-phase fi action were determined on the paraf fin-embedded nodes. MAIN OUTCOME MEASURES: The groups with or without recurrence were compared in terms of disease-free survival (DFS) and overall survival (OS). These su rvival parameters were correlated with DNA ploidy and S-phase fraction. RESULTS: By univariate analysis, clinicopathologic factors did not predict OS. A higher Clark's level of invasion and more than 3 positive lymph nodes were associated with shorter DFS (p < 0.05). Tumour thickness and S-phase fraction did not correlate with either DFS or OS. Patients with diploid lym ph-node metastases had an 87% 12-month survival compared with 41% for those with aneuploid tumours. CONCLUSIONS: DNA ploidy may be used as a prognostic index in patients with lymph-node metastases. This could be particularly useful in the context of sentinel lymph-node mapping by which more patients are being identified wit h single microscopic lymph-node involvement.