What Is Melanoma?

Melanoma is a form of skin cancer. It develops from melanocytes, which are melanin-producing cells found in the skin.1 Early diagnosis is crucial as survival rates drop the later it is diagnosed.2 


As an organ, the skin plays essential roles in protecting the body, regulating temperature and sweat, and removing waste products.1 The skin comprises the epidermis and dermis, with melanocytes located deep in the basal layer of the epidermis.1,2 These cells produce melanin, the pigment that gives skin its natural color and protects against UV radiation.1 This article will review the stages, causes, symptoms, treatment options, diagnosis, and risk factors associated with melanoma.

Stages of melanoma

The stage of melanoma depends on the thickness of the tumor and whether it has spread to the surrounding skin and tissues. Identifying the stage to which the cancer has progressed is the first step in deciding the most effective treatment. There are 5 stages of melanoma:

  • Stage 0 - lso known as melanoma in situ, the cancer cells are only found in the epidermis.3 At this stage, the cancer cannot spread, which makes it easy to treat through surgery to remove the infected tissue3
  • Stage 1 - The cancer is only present in the skin and has not spread any further.4 This stage can be broken into stages 1A and 1B. Stage 1A means the melanoma is less than 1 mm thick, while stage 1B means the melanoma's thickness is between 1 and 2 mm. Most people who are diagnosed at stage 1 will survive and live longer than 5 years from diagnosis5
  • Stage 2 - Only found in the skin and broken into stages 2A, 2B, and 2C.6 The outermost layer of the skin appears to be broken under a microscope during this stage, and at stage 2C, it can be thicker than 4 mm.6 Roughly 80% of people diagnosed with stage 2 cancer will survive for 5 plus years from diagnosis5
  • Stage 3 - The cancer is no longer only found in the skin and has spread to the lymph nodes.7 Approximately 70% of people diagnosed with stage 3 cancer will survive for 5 plus years from diagnosis5
  • Stage 4 - The most severe stage, the cancer has spread beyond the skin and lymph nodes into various distant organs such as the brain, liver, lungs, and other areas of the skin.8 Non-age standardized survival statistics suggest that almost 30% of people live longer than 5 years from their stage 4 diagnosis5

Causes of melanoma

UV radiation exposure is the primary cause of melanoma development and can occur from tanning and the use of sunbeds.9 Dangerous overexposure to UV light from the sun and sunbeds is the main environmental factor for melanoma development. In the UK, roughly 85 out of 100 melanomas are due to UV light overexposure.9 Sunburns can increase the risk of developing melanomas, and the risk continues to increase if you continue to get sunburnt.9 Fair-skinned individuals and those with freckles, who burn easily, are more at risk of developing melanoma.9 Meanwhile, individuals with darker skin tones have greater natural protection.9 Severe UV exposure can damage skin cell DNA. This damage can cause the cells to constantly multiply into more cells which causes cancer.

Signs and symptoms of melanoma

The most obvious sign of melanoma to look out for is a new mole or a change in the appearance of an existing mole. You should keep an eye on moles  that are changing in size, colour and shape and asymmetric and irregularly bordered moles.10

Management and treatment for melanoma

The treatment for melanoma depends on the location of the cancer and the patient's overall health and fitness. When melanoma has not spread, the main treatment is usually surgery, which involves removing the cancerous skin and the surrounding tissue.1,2 However, if the cancer has metastasized and spread to other parts of the body, traditional treatment options include chemotherapy.11 In recent years, novel treatments such as immunotherapy, targeted cancer drugs, radiotherapy, laser therapy, and cryotherapy are increasingly being used.2,8 These treatments may be used in combination with traditional treatments.

Diagnosis of melanoma

Regularly inspecting your own body is a great way to detect any abnormal markings, and the ABCDE checklist is a useful tool for identifying suspicious moles.and stands for:10

  • A: Asymmetrical
  • B: Border
  • C: Colour
  • D: Diameter
  • E: Evolving

If you notice any moles that fit these criteria, it's important to have them examined by a doctor. Diagnosis typically begins with a physical examination of the skin, followed by a biopsy of any suspicious moles.6 If cancer is confirmed, further tests may be needed to determine the stage of the disease. After diagnosis, your doctor will typically check for swollen lymph nodes using an ultrasound and a lymph node biopsy.6 This is important because it can help determine whether the cancer has spread to other parts of the body.

Risk factors

There are several lifestyle factors and medical conditions that can increase your risk of developing melanoma.9 These risk factors include:

  • Exposure to UV light
  • The number of moles on your body - individuals with a larger number of moles or those with abnormally shaped and large moles are at a greater risk of developing melanoma
  • Your skin type, hair and eye color
  • Age -  As you age, your risk of developing melanoma also increases, with over 25% of those diagnosed with melanoma in the UK being older than 75
  • Certain medical conditions -  such as inflammatory bowel disease (including Crohn's disease and ulcerative colitis), can also increase your risk of developing melanoma.9 Additionally, having a weakened immune system can further increase your risk


How can I prevent melanoma?

The best way to prevent melanomas is by protecting your skin against UV damage. This can be done by wearing sunscreen, sunglasses, long-sleeved clothes, and staying in the shade.9 

How common is melanoma?

Melanoma is the fifth most common cancer in the UK, with 16,700 people diagnosed each year, according to Cancer Research UK.1,9

When should I see a doctor?

If you notice any new moles or changes in existing ones, it's important to see a doctor as soon as possible.


Melanoma is a serious and potentially deadly form of skin cancer, but it can be treatable if diagnosed at an early stage. However, if the melanoma has metastasized, or spread to other parts of the body, the prognosis is poor and the survival rate is low. That's why it's crucial to have regular inspections and to go to your doctor if you notice any abnormal moles.


  1. What is melanoma? [Internet]. [cited 2023 Apr 21]. Available from: https://www.cancerresearchuk.org/about-cancer/melanoma/about
  2. Davis LE, Shalin SC, Tackett AJ. Current state of melanoma diagnosis and treatment. Cancer Biology & Therapy [Internet]. 2019 Nov 2 [cited 2023 Apr 21];20(11):1366–79. Available from: https://doi.org/10.1080/15384047.2019.1640032
  3. Melanoma in situ (Stage 0) [Internet]. [cited 2023 Apr 21]. Available from: https://www.cancerresearchuk.org/about-cancer/melanoma/stages-types/melanoma-in-situ-stage-0
  4. Stage 1 [Internet]. [cited 2023 Apr 21]. Available from: https://www.cancerresearchuk.org/about-cancer/melanoma/stages-types/stage-1
  5. Survival [Internet]. [cited 2023 Apr 21]. Available from: https://www.cancerresearchuk.org/about-cancer/melanoma/survival
  6. Stage 2 [Internet]. [cited 2023 Apr 21]. Available from: https://www.cancerresearchuk.org/about-cancer/melanoma/stages-types/stage-2
  7. Stage 3 [Internet]. [cited 2023 Apr 21]. Available from: https://www.cancerresearchuk.org/about-cancer/melanoma/stages-types/stage-3
  8. Stage 4 [Internet]. [cited 2023 Apr 21]. Available from: https://www.cancerresearchuk.org/about-cancer/melanoma/stages-types/stage-4
  9. Risks and causes of melanoma [Internet]. [cited 2023 Apr 21]. Available from: https://www.cancerresearchuk.org/about-cancer/melanoma/risks-causes
  10. Symptoms of melanoma [Internet]. [cited 2023 Apr 21]. Available from: https://www.cancerresearchuk.org/about-cancer/melanoma/symptoms
  11. Mishra H, Mishra PK, Ekielski A, Jaggi M, Iqbal Z, Talegaonkar S. Melanoma treatment: from conventional to nanotechnology. J Cancer Res Clin Oncol [Internet]. 2018 Dec 1 [cited 2023 Apr 21];144(12):2283–302. Available from: https://doi.org/10.1007/s00432-018-2726-1
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Christina Weir

Master of Science - MS, Biotechnology, Bioprocessing & Business Management, University of Warwick

Hey there, I'm Christina (Krysia), and I'm thrilled to be an article writer for Klarity! I recently completed my master's degree in Biotechnology from the University of Warwick, and currently, I work at The Francis Crick Institute in Science Operations. I love being involved with the institute's exciting biomedical research and have a passion for Science Communications. My goal is to simplify science so everyone can join in and learn something new!

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