Final Version of 2009 AJCC Melanoma Staging and Classification

Thursday December 10, 2009

In a recently published article Charles Balch and colleagues report on the revision of the staging system for cutaneous melanoma based on data from an expanded American Joint Committee on Cancer (AJCC) Melanoma Staging Database.

According to the abstract, the staging recommendations, which revise and clarify TNM classifications and stage grouping criteria, were made on the basis of a multivariate analysis of 30,946 patients with stages I, II, and III melanoma and 7,972 patients with stage IV melanoma.

As stated in the abstract, “the findings and new definitions include the following:

• In patients with localized melanoma, tumor thickness, mitotic rate (histologically defined as mitoses/mm2), and ulceration were the most dominant prognostic factors.
• Mitotic rate replaces level of invasion as a primary criterion for defining T1b melanomas.
• Among the 3,307 patients with regional metastases, components that defined the N category were the number of metastatic nodes, tumor burden, and ulceration of the primary melanoma.
  
• For staging purposes, all patients with microscopic nodal metastases, regardless of extent of tumor burden, are classified as stage III. Micrometastases detected by immunohistochemistry are specifically included.
• On the basis of a multivariate analysis of patients with distant metastases, the two dominant components in defining the M category continue to be the site of distant metastases (nonvisceral v lung v all other visceral metastatic sites) and an elevated serum lactate dehydrogenase level”.
  

The authors conclude that “using an evidence-based approach, revisions to the AJCC melanoma staging system have been made that reflect our improved understanding of this disease”. The revisions will be formally incorporated into the seventh edition (2009) of the AJCC Cancer Staging Manual and implemented by early 2010.

Source:  Journal of Clinical Oncology
Early Release, published online ahead of print Nov 16 2009
http://jco.ascopubs.org/cgi/content/abstract/JCO.2009.23.4799v1