What Is Melanoma Staging?

Staging Helps Healthcare Professionals Understand the Risk of Cancer Recurrence

To better identify patients’ individual risk of SLNB positivity, Castle Biosciences now integrates clinicopathologic factors with your 31-GEP score using an artificial intelligence neural network trained algorithm. This is then used to decide on treatment plans that are appropriate for each stage of melanoma. Tumors are staged as I, II, III, or IV according to the American Joint Committee on Cancer (AJCC) Staging System. Stage I tumors have a better outlook (prognosis) than those in stage II, III, or IV.

In melanoma, healthcare professionals use traditional pathology factors to initially stage melanoma. These are tumor thickness (commonly referred to as Breslow’s depth or thickness), ulceration status, and presence of melanoma cells in your lymphatic system. X-rays, blood tests, and computed tomography (CT) scans may also be used to confirm melanoma stage.

Staging, based on these traditional pathology factors is then used to guide decisions on:

  • Type of surgery to completely remove the melanoma
  • Whether to consider and undergo a sentinel lymph node biopsy (SLNB) surgical procedure
  • Follow-up management plan, including frequency and extent of office visits, routine imaging studies, adjuvant therapy, and/or enrollment in clinical trials

Sentinel Lymph Node Biopsy (SLNB) Surgical Procedure

Depending upon the traditional pathology staging features from your initial biopsy (tumor thickness, ulceration status, or other features of concern), your healthcare professional may discuss the SLNB surgical procedure with you if your melanoma has features that suggest it may be more aggressive. 

For some patients, melanoma spreads first to the lymph nodes. Melanoma can also spread through the blood, avoiding the lymph nodes completely. To find the “sentinel” node (the first node to which the melanoma could have spread), the surgeon performs the following steps:


Step 1: Injects a radioactive liquid or dye (or both) into the area of the melanoma


Step 2: Checks to see which nodes are the first to drain fluid from the skin


Step 3: Identifies which lymph nodes have absorbed radiation or turned blue


Step 4: Removes these nodes for examination by a pathologist under a microscope

The SLNB surgical procedure is performed to provide additional staging information and has not been shown to improve survival. That is, the SLNB surgical procedure provides prognostic or risk of recurrence information but it is not therapeutic by itself.

The SLNB surgical procedure also carries some risks, which is why it is not performed in all patients, and it is important to determine if it is right for you. For instance, surgical complications happen in up to 11 percent of patients. In addition, for as many as 18 percent of patients, it may provide a false negative result (meaning that no melanoma cells were found in your lymph nodes but you may later have a recurrence or metastasis to your lymph nodes). Using traditional pathology staging factors to identify who should have a SLNB surgical procedure is not 100 percent accurate; using these criteria, melanoma cells will only be found in approximately 12 percent of surgeries.

For many patients eligible for an SLNB, genomic testing with DecisionDx®-Melanoma can provide important information to consider before deciding to have this surgical procedure. This test looks at the biology of your individual tumor to predict how aggressive your melanoma may be, to help determine the risk of your cancer recurring.

Of tumors that were initially staged as low risk, two out of three patients who develop metastatic disease and succumb to their melanoma tumor were initially classified as Stage I or II.

Using DecisionDx-Melanoma Genomic Testing to Improve Upon Traditional Staging

Today, healthcare professionals are realizing that traditional approaches to staging melanoma may lack accuracy. Sadly, the majority of melanoma-related deaths occur in patients who were originally thought to have early-stage cancer. 


To provide even more individualized tumor information, Castle Biosciences now integrates clinicopathologic factors with the 31-GEP score using two validated algorithms.

These Integrated Test Results (i31-ROR and i31-SLNB) are designed to provide more precise and personalized predictions for the risk of your cancer coming back and likelihood of sentinel lymph node positivity.

DecisionDx-Melanoma uses the latest molecular diagnostic techniques to better understand the biological behavior of tumors and the risk of cancer recurring.

Learn How
Can Predict the Risk of Your Melanoma Recurring or Spreading


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What’s Next?

What Are the Treatment Options for Melanoma?

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DecisionDx-Melanoma Test?