Disease-Free Survival for Patients with Thin Melanomas according to the American Joint Committee on Cancer 8th Edition


The recently implemented AJCC 8th edition TNM staging system for malignant melanoma (MM) changed the definition for T1a and T1b tumours.


To analyse differences in disease-free survival (DFS) among patients with thin MM staged according to both AJCC 7th and 8th editions.


An observational study including 285 patients with cutaneous thin MM (thickness ≤1 mm). Cases were staged as T1a and T1b using both 7th and 8th editions. Neither regional nor visceral diseases were present at diagnosis. DFS curves were generated according to the Kaplan-Meier method.


An 8% shift of patients from a T1a towards a T1b stage group was observed after applying the AJCC 8th edition. According to this 8th edition, DFS for T1a patients was significantly longer than for T1b patients (log-rank test; p = 0.005); 5-year DFS for T1a and T1b was 100 and 95%, respectively (Wilcoxon test; p = 0.002). According to the AJCC 7th edition, DFS did not significantly differ for T1a and T1b patients; 5-year DFS for T1a and T1b was 99 and 97%, respectively (p > 0.05).


The AJCC 8th edition seems to be a better tool for staging thin melanomas.