What tests detect melanoma?

The most aggressive form of cancer is melanoma skin cancer type. It develops when the cells that are responsible to produce melanin (the pigment that gives skin its color) in skin, called melanocytes, mutate and grow uncontrollably. The factor that significantly increases the chances of successful treatment and survival of the patient is early detection of the cancer. Fortunately, with such advancement and use of modern technology in the medical world, there are several tests and diagnostic techniques available to detect melanoma accurately, and this is what we are going to discuss further in this blog……..

What is Melanoma?

Melanoma is a type of skin cancer that develops from melanocytes, the cells that produce melanin, the pigment that gives skin its color. It’s a serious cancer that can spread to other parts of the body if not detected and treated early.

Types of Melanoma

1. Superficial Spreading Melanoma: The most common type, often spreading across the surface of the skin before penetrating deeper.
2. Nodular Melanoma: A more aggressive form that grows vertically into the skin.
3. Lentigo Maligna Melanoma: Typically found in older adults and often appears on sun-damaged skin.
4. Acral Lentiginous Melanoma: Less common, typically found on the palms, soles, or under the nails.

Due to melanoma’s aggressive nature, early detection is critical. The following tests and procedures play a key role in identifying melanoma at an early stage.

Self-Examination and Visual Inspection

The first step in detecting melanoma often begins with self-examination. Checking the skin regularly for new moles, changes in existing moles, or unusual growths can help identify potential melanoma early.

The ABCDE Rule for Melanoma Detection:

• A – Asymmetry: One half of the mole looks different from the other.
• B – Border Irregularity: The edges are uneven or blurred.
• C – Color Variation: Multiple colors, including shades of brown, black, or red.
• D – Diameter: Moles larger than 6mm (about the size of a pencil eraser).
• E – Evolving: Any changes in size, shape, color, or symptoms such as itching or bleeding.

If you notice any of these warning signs, it’s important to consult a dermatologist immediately for further evaluation.

Clinical Skin Examination- Melanoma Diagnosis

A clinical skin examination by a dermatologist is the next step if a suspicious mole or lesion is detected. There are different methods by which the diagnosis for melanoma is done in the patient. These are…..

Dermoscopy

Dermoscopy (also known as dermatoscopy or epiluminescence microscopy) is a non-invasive technique that allows dermatologists to examine skin lesions more closely. Using a dermatoscope, a dermatologist can assess pigmented lesions and determine whether a mole is benign or potentially malignant.

Biopsy Procedures

If a suspicious lesion is identified, the next step is typically a biopsy. A biopsy involves removing a sample of tissue for laboratory analysis to determine if the cells are cancerous.

There are different types of biopsy used to diagnose melanoma like excisional biopsy, a method in which the entire lesion is removed along with a margin of normal tissue for testing. Another is, incisional biopsy, in which only a portion of the lesion is removed for analysis. Another two are punch and shave biopsy, a little less commonly used methods.

Histopathological Examination

The gold standard for confirming melanoma is a histopathological examination. After a biopsy, a pathologist examines the tissue sample to determine whether melanoma cells are present and, if so, how advanced the cancer is. 

The key factors that are analyzed in this test are Breslow Thickness, which measures the depth of the tumor in millimeters, which helps determine the stage of melanoma, Clark Level, which describes how deeply the tumor has penetrated the skin layers, Ulceration, which indicates whether the surface of the tumor is broken, which may suggest a more aggressive form and mitotic Rate, which examine the rate at which the cancer cells are dividing, indicating how quickly the tumor is growing.

Sentinel Lymph Node Biopsy (SLNB)

A Sentinel Lymph Node Biopsy (SLNB) is a procedure to determine if cancer has spread from a primary tumor to nearby lymph nodes, by identifying and removing the first lymph node(s) (sentinel lymph node) draining the tumor area for testing.

Imaging Tests for Advanced Melanoma

For cases where melanoma may have spread beyond the skin, imaging tests can help determine the extent of the disease.

Common Imaging Tests Include:

• CT (Computed Tomography) Scan
• MRI (Magnetic Resonance Imaging)
• PET (Positron Emission Tomography) Scan
• X-Ray

These imaging tests help doctors develop a comprehensive treatment plan based on the stage of melanoma.

Genetic and Molecular Testing

In advanced cases of melanoma, genetic and molecular testing may be conducted to identify mutations that can guide treatment decisions.

Common Mutations in Melanoma:

• BRAF Mutation: Present in about 50% of melanomas, targeted therapies such as BRAF and MEK inhibitors can be used.
• NRAS Mutation: Found in about 20% of melanomas, though treatment options are limited.
• KIT Mutation: More common in acral and mucosal melanomas, targeted therapies may be available.

Genetic testing helps determine whether patients may benefit from targeted therapies or immunotherapy.

Blood Tests and Biomarkers

Although not used for diagnosing melanoma, blood tests may be used in advanced cases to monitor disease progression and assess the effectiveness of treatment.

The common biomarkers in melanoma are Lactate Dehydrogenase (LDH), of which high levels in the patient’s body indicate advanced melanoma or metastasis. Another one is S100 Protein, of which elevated levels in the patient’s body may suggest melanoma recurrence or progression.