2018 ASCO Annual Meeting!
Session: Melanoma/Skin Cancers
Type: Oral Abstract Session
Time: Monday June 4, 8:00 AM to 11:00 AM
Location: Arie Crown Theater
External validation of the 8th Edition Melanoma Staging System of the American Joint Committee on Cancer (AJCC): Effect of adding EORTC sentinel node (SN) tumor burden criteria on prognostic accuracy in stage III.
2018 ASCO Annual Meeting
J Clin Oncol 36, 2018 (suppl; abstr 9500)
Author(s): Max Fullah Madu, Viola Franke, Bart Van De Wiel, Willem M.C. Klop, Katarzyna Józwiak, Michel W.J.M. Wouters, Alexander Christopher Jonathan Van Akkooi; Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam, Netherlands; Antoni van Leeuwenhoek - NKI (Netherlands Cancer Institute), Amsterdam, Netherlands; Netherlands Cancer Institute, Amsterdam, Netherlands; The Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam, Netherlands
Background: Now that effective adjuvant therapy has arrived in melanoma, accurate staging and patient selection to optimize a risk/benefit ratio is crucial. The new 8th Edition AJCC staging system for melanoma aims to improve risk stratification. The goal of this study was to externally validate the prognostic and discriminatory ability for survival of the 8th Edition in comparison to the 7th. Methods: Analysis of a prospective cohort of patients treated in the Netherlands Cancer Institute for AJCC 7/8th Edition stage III melanoma between 2000 and 2016. Stage III melanoma was defined as regional lymph node metastases, with or without concurrent local recurrence, (micro)satellite or in-transit metastases. Prognostic factors for melanoma-specific survival (MSS) and distant metastasis-free survival (DMFS) were analyzed. Survival differentiation of the 7th and 8th edition was assessed with log-rank tests and Cox proportional hazards models. Discriminatory ability was compared using the area under the curve (AUC) of the receiver operating statistic (ROC) obtained with Cox models. Results: 640 patients were included with a median follow-up of 59 months (interquartile range 32-108). Median MSS was 138 months, DMFS 96 months. Age, Breslow thickness, ulceration of the primary tumor and number of positive lymph nodes (N) were significant prognostic parameters for MSS and DMFS. The 8th Edition performed similarly to the 7th in terms of survival discrimination, but failed to differentiate MSS between stage IIIA and IIIB after correction for sex and age. Both in 7th and 8th edition stage IIIA melanoma, patients with an SN metastasis size < 1 had excellent DMFS and MSS. Conclusions: The AJCC 8th edition staging system differentiates survival slightly worse than the 7th edition. Survival in both 7th and 8th edition stage IIIA melanoma is heterogeneous and can be sub-classified according to EORTC SN tumor burden, which can aid clinical decision-making concerning adjuvant therapy.