Melanoma Staging Gaps: Where AJCC Falls Short and GEP Testing Fits

Welcome back to another Dermatology Times Expert Perspectives series. In "Melanoma Staging Gaps: Where AJCC Falls Short and GEP Testing Fits," Gaurav Singh, MD, MPH, FACMS, a Mohs surgeon at City of Hope Cancer Center Chicago, opens the series on cutaneous melanoma by examining the limits of conventional staging.

Why Staging Alone Falls Short

Dr. Singh describes AJCC staging as critical to melanoma management, but he notes that staging is not perfect. Some patients with stage I disease go on to develop metastasis despite receiving every element of current standard care. Conversely, some patients with advanced melanoma do very well after surgery and immunotherapy. He frames staging as a strong launch pad for next steps that does not always tell the complete picture.

Mortality Data Reveal Hidden Risk

He cites national mortality data to make the point. Roughly 8,000 people in the US die from melanoma each year, and about a quarter of them had early-stage disease. About two-thirds of those patients had a negative sentinel lymph node biopsy, and practice varies widely in what happens next for that group. A tool that identifies which stage I melanomas behave worse than they appear, and which stage II patients with negative nodes will recur, could meaningfully improve outcomes. Dr. Singh says the 31-gene expression profile test, DecisionDx-Melanoma, has been shown to do exactly that by finding the needle in the haystack.

Prognostic Features Staging Misses

For a high-risk stage I patient, doing more may mean additional imaging or a sentinel lymph node biopsy. For a stage II patient with a high GEP score, it may mean added imaging despite a negative node biopsy. Dr. Singh then reviews features that AJCC staging cannot capture. For example, head and neck location carries worse outcomes but is not part of staging. Mitotic rate was removed from AJCC staging, even though tumors with more mitoses tend to fare worse. Immunocompromised patients, whether from illness or medications, may also see their melanomas behave unpredictably. Combining traditional staging with GEP testing, he argues, places patients into the right risk category more accurately.

Up next, in "GEP Assays in Melanoma: Comparing the Evidence and NCCN Risk Thresholds," Dr. Singh compares the commercially available assays and weighs the evidence behind each against NCCN risk thresholds.