AJCC Revises Melanoma Staging System

An array of skin moles on someone's back
An array of skin moles on someone’s back
The evidence-based revisions are intended to improve patient treatment planning.

In the 8th edition of the American Joint Committee on Cancer (AJCC) staging system for cutaneous melanoma, particular focus was directed toward the clarification of major themes and terminology, the introduction of clinically relevant revisions, and the creation of a new, contemporary international database, according to a recent publication in CA: A Cancer Journal for Clinicians.

In an effort to update the melanoma staging system of the AJCC, a large database was compiled that comprised >46,000 patients from 10 centers worldwide, with stage I, II, or III melanoma diagnosed since 1998. The AJCC Melanoma Expert Panel introduced several important changes to the Tumor, Nodes, Metastasis (TNM) classification and stage grouping criteria.

Among the major revisions in the 8th edition of the AJCC Cancer Staging Manual are the following:

  • Tumor thickness measurements will now be recorded to the nearest 0.1 mm;
  • Definitions of T1a and T1b have been revised;
  • Pathologic (but not clinical) stage 1A has been revised to include T1b N0 M0;
  • The N category descriptors of “microscopic” and “macroscopic” for regional node metastasis have been redefined as “clinically occult” and “clinically apparent,” respectively;
  • Prognostic stage III groupings are based on N category criteria and T category criteria, and have been increased from 3 to 4 subgroups (ie, stages IIIA-IIID);
  • Definitions of N subcategories have been revised;
  • Descriptors have been added to each M1 subcategory designation for lactate dehydrogenase level;
  • A new M1d designation has been added for central nervous system metastases.

These evidence-based changes are intended to help guide patient treatment planning, offer improved prognostic assessments, refine the selection and stratification of patients entering clinical trials, and provide an updated framework for the classification and staging of individuals with cutaneous melanoma. Broad-based educational initiatives are necessary for clinicians to comprehend and effectively integrate the information contained in these revisions into their clinical practice and registry-related activities.

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Gershenwald JE, Scolyer RA, Hess KR; for members of the American Joint Committee on Cancer Melanoma Expert Panel and the International Melanoma Database and Discovery Platform. Melanoma staging: evidence-based changes in the American Joint Committee on Cancer Eighth Edition Cancer Staging Manual [published online October 13, 2017]. CA Cancer J Clin. doi: 10.3322/caac.21409