RESUMEN
BACKGROUND: The 8th edition of TNM has introduced new rules for staging cutaneous melanoma. OBJECTIVE: To compare TNM 7th and 8th editions in defining pathological stages of melanoma. METHODS: A population-based series of 1847 skin melanoma from Romagna cancer registry (Italy) incident during 2003-2012 has been used to measure the agreement (with Cohen's kappa) between TNM 8th and 7th editions in defining melanoma stage. Disease-specific survival has been computed for each stage according to TNM 7th and 8th. RESULTS: The agreement between the two TNM editions was quite good when considered on average (kappa = 70.7%), moderate for stage I (61.5%), nearly perfect for stage II (95.0%), but extremely poor for stage III (8.1%). The overall melanoma-specific observed survival was 90.8% at 5 year and 88.9% at 10 year with a strong prognostic effect of stage. CONCLUSION: TNM 8th edition introduces several changes which do not seem really helpful in addressing the care of stage I melanoma and may complicate the definition and comparability of stage III.