How Fast Melanoma Grows?

Quick Summary

Melanoma does not grow at the same pace for everyone. Some people develop it slowly over the years, while others can develop it faster in just a few weeks. One-third of melanomas may grow 0.5 mm per month, and in some rare cases you will notice extreme rapid development. Early detection and treatment within your trusted healthcare professionals can save your life.

 

What is Melanoma?

Melanoma is a type of skin cancer that begins in melanocytes, these are cells that produce melanin, the pigment that gives skin its colour. Melanoma is less common than other skin cancers, but more dangerous because it can spread quickly to other parts of your body.

Melanoma grows in two main phases:

• Radial growth phase: This is when cancer cells spread across the surface of the skin. At this stage, melanoma looks like a flat or slightly raised mole that changes slowly and the growth is slower at this point.
• Vertical growth phase: This is when cancer cells start growing deeper into the skin and may reach blood vessels or lymph channels that increases the risk of melanoma spreading to the other parts of the body.

How fast melanoma moves from radial phase to vertical phase greatly varies. This is why melanomas look harmless for years, while others become aggressive very quickly.

 

Factors Affecting Melanoma Growth

Genetics

People with family history of melanoma may have inherited traits that increase risk. Some genetic conditions and skin types also play a role that cause cancer cells to grow faster.

 

Environmental factors

Ultraviolet (UV) exposure is the strongest environmental risk factor for melanoma. You can be exposed from sources like the sun or sunbeds.

Also, people who had severe sunburns from childhood or teenage years, fair skin, light hair, freckles, and large numbers of moles are at higher risk.

Related read: 5 Key Suspicious Mole Symptoms You Should Never Ignore

 

Immune system response

Your immune system controls abnormal cell growth. If you have a weakened immune system, melanoma may grow and spread faster.

People who had organ transplant, are undergoing chemotherapy, or take long-term immunosuppressive medication are more at risk of aggressive melanoma. These individuals need regular skin checks and assessment.

 

Growth Rates of Different Types of Melanoma

Not every melanoma growth is at the same speed. Some are easier to detect while others are more difficult and more dangerous types.

 

Fast growing vs slow growing melanoma

Experts suggest that one-third of melanomas develop at a rate of 0.5 mm or more per month. This size refers to growth in depth, which is a key factor in knowing how melanoma is to spread.

Slow-growing types tend to stay close to the skin surface for a long time. Fast-growing melanomas can be noticeable in a short time when skin changes develop faster.

 

Types of melanoma

Type	How Fast It Grows	What It’s Like	Why It’s Important
Nodular melanoma	Very fast	Grows deeper into the skin early with no warning signs on your skin.	It can become serious within weeks or months, so early detection is important.
Superficial spreading melanoma	Slow to moderate	Spread first into the skin before going deeper.	Slower changes make it easier to detect and treat at first sign.
Lentigo maligna melanoma	Very slow	It usually appears on skin that is damaged by the sun of older adults.	May stay harmless for a long time but needs regular checks and treatment.

 

How Fast Does Melanoma Grow?

How fast melanoma grows differ on each person and the type of melanoma.

In some rare cases, the skin cancer can grow thicker and quickly, about 15 mm in 8 weeks. This does not always happen, but it only shows that it can be an aggressive melanoma if not found and treated early.

Some fast-growing melanomas can be life-threatening within 6 weeks. This is the reason why UK skin experts treat quick-changing moles as urgent cases. Melanoma growth is measured using Breslow thickness, to know the tumour stage in the TNM (Tumour, Node, Metastasis) staging system for melanoma skin cancer. The thicker growth means higher risk of spread.

Related read: Swollen Mole Like a Spot? What It Might Mean

 

How Fast Do Melanomas Spread to Other Areas?

Melanoma can be more dangerous if it has spread beyond the skin. This is called metastasis.

In the early stage, 15 to 26% of melanoma cases may spread to other areas of the body in 1 to 3 years if left untreated. Melanoma usually spreads first to the lymph nodes and may travel to organs such as the lungs, bones, liver, or brain.

Factors that may increase the risk of spread include:

• Thicker tumour
• Ulceration of the skin over the melanoma
• Cancer cells found in lymph nodes
• Cancer cells are quickly dividing

 

Rare Types of Melanoma

There are other forms of rare melanoma that behave differently and they are harder to detect.

Melanoma Type	Area It Develops	Growth Pattern	Why It’s Often Missed
Subungual melanoma	Under fingernails or toenails	Growth speed differs Often detected late	Commonly mistaken for a bruise, injury, or nail infection
Brain melanoma (metastatic)	Brain (spread from skin melanoma)	It can develop over several months Some tumours may grow for 6 months or more before detection	Symptoms can appear gradually or look like other brain or nerve problems.

Symptoms and Diagnosis

Melanoma starts to appear as a new or changing mole. Dermatologists recommend using the ABCDE rule:

• Asymmetry: One half is different from the other side
• Border: There are irregular edges
• Colour: Multiple colours are seen on one mole
• Diameter: Size is larger than 6 mm
• Evolving: Continues changing in size, colour, or shape

Another sign is that one mole is noticeably different from all other moles in the body, this is called the “ugly duckling rule”.

Diagnosis involves removing the mole by excising it and examining it under a microscope. Pathology reports include Breslow thickness and mitotic rate, which can predict how fast the skin cancer may spread and grow.

Related read: When to Get Moles Checked: Signs You Mustn’t Ignore

 

Stages of Melanoma Progression

Stage 0 and Stage I

In this stage, melanomas are limited to the skin and often grow slowly and are cured with surgery.

 

Stage II and Stage III

The melanomas are thicker and may involve lymph nodes. There may be growth and spread at these stages.

 

Stage V

Melanoma has already been spread to other organs. Melanoma can progress quickly without treatment at this stage.

 

Treatment Options and Their Impact on Growth

Treatment depends on the stage and whether it has already started to spread.

• Surgical excision: this option is used for early-stage melanoma. The cancer is completely removed and this is often curative.
• Sentinel lymph node biopsy: This type of biopsy is recommended for some higher risk cases under UK NICE guidelines. It checks if melanoma has spread to nearby lymph nodes.
• Immunotherapy: It helps the immune system recognise and attack cancer cells, which can slow or stop growth. This is recommended to be used for advanced melanoma.
• Targeted therapy: Recommended for melanomas with certain genetic changes. This works by shrinking tumours and helps control the progression of cancer.

Related read: Understanding the Removal of Malignant Melanoma: Surgery

 

Conclusion: Why Early Detection Matters

Melanoma does not grow the same way for every person. Some grow slowly and may not cause a concern at first, but others can grow and spread in a span of weeks.

When melanoma is found early, treatment is usually very effective, around 99% of people with melanoma in the early stage survive. But when melanoma spreads to other organs, survival drops to 33%.

This is why it is important to understand how fast melanoma can grow. If you notice any new or changing moles, get them checked as soon as possible. Acting early and seeking professional advice can save your life.