How Fast Does Melanoma Spread?

There are four primary types of melanoma:

• Superficial spreading melanoma (SSM). SSMs are a slow-growing type of melanoma. They start as a discolored patch on your skin that grows over months or years. They’re called superficial spreaders because they grow horizontally across the skin’s surface rather than into deeper layers. SSMs are the most common type of melanoma, accounting for approximately 70% of all cases.
• Lentigo maligna melanoma. These types of melanoma are also slow-growing. They’re usually brown with irregular borders and often appear on sun-damaged skin. They account for approximately 4% to 15% of all melanoma cases.
• Nodular melanoma: These types of melanoma are the most invasive and fast-growing melanomas. They initially present as a dark lump on the skin’s surface, but they can penetrate deep within the skin within a few months. They account for about 15% to 20% of melanoma diagnoses and about 40% of melanoma-related deaths, due to their rapid growth and early metastasis to other areas of the body.
• Acral lentiginous melanoma: These melanomas are rare, accounting for 2% to 3% of all melamonas. They appear as brown or black lesions, typically in the nailbeds, the palms of the hands, or the soles of the feet. For this reason, they’re often diagnosed late, worsening the outlook for people with this type of melanoma.

Seek medical attention immediately if you notice any changes in your skin, such as new growths or a rapidly enlarging mole or lump. Fast-growing melanomas can spread within months.

As with other types of cancers, the earlier you catch and treat melanoma, the better your outlook.

The stage at which a melanoma is diagnosed affects survival rates. Doctors stage melanoma in five stages. The 5-year relative survival rates are noted below for each stage.

Treatments for melanoma have improved significantly over the years. The survival rates noted above may not reflect these advancements.