Latest AJCC Edition Staging System May Not Be As Effective in Differentiating Survival in Melanoma

CHICAGO―An external validation of the American Joint Committee on Cancer (AJCC) 8th edition staging system found that the latest edition maintained a similar prognostic accuracy as its predecessor, but may not differentiate survival among patients with early-stage melanoma as well as the 7th edition, according to data presented at the American Society of Clinical Oncology 2018 Annual Meeting on Monday, June 4.¹

Accurate staging and patient selection is critical to establish an appropriate risk/benefit ratio. In efforts to improve risk stratification for patients with melanoma with the 8th Edition AJCC staging system, study authors conducted a study comparing the prognostic and discriminatory ability for survival with the 7th and 8th Editions. 

For this analysis, researchers assessed the outcomes of a prospective cohort of 640 patients from the Netherlands Cancer Institute who were treated for AJCC 7/8th Edition stage III melanoma between 2000 and 2016. Specifically, melanoma-specific survival (MSS) and distant metastasis-free survival (DMFS) were studied as prognostic factors; survival differentiation seen in the 7th and 8th editions were also statistically analyzed. 

Stage III melanoma was defined as regional lymph node metastases, with or without concurrent local recurrence, (micro)satellite or in-transit metastases.

The median follow-up was 59 months. The data showed a median MSS of 138 months and DMFS of 96 months. Prognostic parameters such as age, ulceration of primary tumor, Breslow thickness, and the quantity of positive lymph nodes were deemed to be significant factors for MSS and DMFS. 

Compared to the 7th Edition, the 8th Edition was comparable regarding survival discrimination, but did not differentiate between MSS stage IIIA and IIIB after adjusting for age and gender. The authors did note that for stage IIIA melanoma in both editions, patients with an SN metastasis size less than 1 — an entry criterion used for previous studies — demonstrated excellent DMFS and MSS.

While the AJCC 8th edition staging system held up to external validation in regards to prognostic accuracy, survival differentiation, albeit comparable, was a bit worse compared to the 7th edition. The authors concluded that “survival in stage IIIA melanoma in the 8th Edition remains heterogeneous. Stage IIIA melanoma can be stratified further by use of Rotterdam/EORTC criteria for SN tumor burden.”

Read more of Cancer Therapy Advisor‘s coverage of the American Society of Clinical Oncology (ASCO) 2018 meeting by visiting the conference page.

Reference

1. Madu MF, Franke V, Van de Wiel B, et al. 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. Oral presentation at the American Society of Clinical Oncology 2018 Meeting; June 1-5, 2018. Chicago; IL.