Overview

Melanoma is a serious and potentially life-threatening form of skin cancer that develops from melanocytes, the cells responsible for producing melanin, the pigment that gives skin its color. Although less common than other types of skin cancer, melanoma is more aggressive and more likely to spread to other parts of the body if not detected early. It can occur on any area of the skin but is most frequently found on areas exposed to the sun, such as the back, legs, arms, and face. Melanoma can also develop in the eyes and, rarely, in internal organs.

Causes

The exact cause of melanoma is complex and involves a combination of genetic, environmental, and lifestyle factors. Major contributing factors include:

• Ultraviolet (UV) exposure: Prolonged exposure to UV radiation from sunlight or tanning beds significantly increases melanoma risk.
• Genetic mutations: DNA damage in skin cells can cause abnormal growth of melanocytes, leading to cancerous changes.
• Family history: Individuals with a family history of melanoma have a higher risk.
• Fair skin: People with light skin, freckles, blonde or red hair, and light-colored eyes are at greater risk.
• Multiple or unusual moles: Atypical (dysplastic) moles or a large number of moles increase the chance of melanoma development.
• Weakened immune system: Immunocompromised individuals, such as organ transplant recipients, are at increased risk.
• Age and gender: While melanoma can affect any age group, it is more common in older adults and slightly more prevalent in men.

Symptoms

Melanoma typically presents as a new mole or changes to an existing mole. The key symptoms include:

• Asymmetry: One half of the mole or spot does not match the other half in shape.
• Border irregularity: The edges are ragged, notched, or blurred.
• Color changes: Uneven color with varying shades of brown, black, tan, red, white, or blue.
• Diameter: Lesions greater than 6 millimeters (about the size of a pencil eraser) are more concerning.
• Evolving: Any change in size, shape, color, or symptoms (itching, bleeding, crusting) over time.
• Non-healing sores: A lesion that does not heal properly.
• Spread to lymph nodes: Swelling or lumps, especially in areas close to the primary melanoma site, can indicate spread.

Diagnosis

Diagnosis of melanoma involves clinical evaluation and confirmatory laboratory procedures:

• Skin examination: Dermatologists assess the skin using the ABCDE criteria (Asymmetry, Border, Color, Diameter, Evolving).
• Dermatoscopy: A dermatoscope magnifies skin features, aiding in the differentiation of benign from malignant lesions.
• Biopsy: A suspicious lesion is removed, either partially or completely, and examined under a microscope for cancer cells.
• Sentinel lymph node biopsy: Performed if melanoma is invasive, to check for spread to nearby lymph nodes.
• Imaging tests: CT scans, MRI, or PET scans may be used to detect metastasis to internal organs in advanced cases.
• Blood tests: May include tests for lactate dehydrogenase (LDH), which can be a marker of advanced disease.

Treatment

Treatment for melanoma depends on the stage of the cancer, location, and overall health of the patient:

• Surgical removal: Early-stage melanomas are typically treated with surgical excision with clear margins.
• Sentinel lymph node dissection: May be done if there is evidence of spread to nearby lymph nodes.
• Immunotherapy: Medications like checkpoint inhibitors (nivolumab, pembrolizumab) help boost the immune system to fight cancer.
• Targeted therapy: For melanomas with specific genetic mutations (BRAF mutations), drugs like vemurafenib or dabrafenib may be used.
• Chemotherapy: Less commonly used today, reserved for advanced melanoma not responding to other treatments.
• Radiation therapy: May be recommended in certain cases, particularly after surgery or for brain metastases.
• Clinical trials: New treatment options and medications are continually being tested and may be available.

Prognosis

The prognosis for melanoma largely depends on how early the cancer is detected and treated:

• Early-stage melanoma: High survival rates, especially when detected before spreading beyond the skin; five-year survival exceeds 90% for stage I.
• Intermediate stages: Survival rates decrease if melanoma spreads to regional lymph nodes.
• Advanced melanoma: Stage IV melanomas with distant metastasis have lower survival rates, but recent advances in immunotherapy have improved outcomes.
• Importance of early detection: Regular skin checks and prompt treatment are crucial for improving long-term outcomes.

With timely diagnosis and modern treatment options, many individuals with melanoma can achieve excellent outcomes, especially in the early stages.