Prognostic factors of cutaneous melanoma and a new staging system proposed by the American Joint Committee on Cancer (AJCC): validation in a cohort of 1284 patients

Abstract

This study, involving a cohort of 1284 evaluable patients, validates the American Joint Committee on Cancer (AJCC) proposal for the introduction of ulceration of primary cutaneous melanoma as an independent prognostic factor of survival. In univariate analyses, ulceration (Hazard Ratio (HR) 1.983; P<0.0001; 95% Confidence Intervals (CI) 1.692-2.325) was a predictor of worse overall survival. In multivariate analyses, ulceration (HR 1.302; P=0.022; (95% CI: 1.039-1.633) retained its prognostic significance for survival independent of tumour thickness (HR 1.101; P<0.0001; 95% CI: 1.055-1.150); mitotic activity (HR 1.039; P=0.005; 95% CI: 1.012-1.067); and age (HR 1.009; P=0.006; 95% CI: 1.003-1.016). Ulceration lost its significance in a subgroup analysis of 256 patients with clinically apparent regional lymph node metastases to the number of lymph nodes involved (HR 1.15; P=0.004; 95% CI:1.047-1.263). Ulceration is prognostically significant in the tumour but not the nodal classification of melanoma, with mitotic activity the second most important prognostic factor after tumour thickness.