Melanoma

How is melanoma diagnosed?

A skin cancer doctor can diagnose melanoma by examining it closely with a dermoscope. It will usually have specific colours or structures that alert the doctor to the possibility of melanoma. Sometimes these clues to diagnosis are hard to see and the melanoma is suspected because of changed appearance in repeated dermoscopic photographs.⁵ When a melanoma is suspected, the doctor will surgically remove the suspicious spot (a procedure known as excision biopsy) so that a skin pathologist can examine the tissue and make a definitive diagnosis.

Melanoma levels and stages

Melanomas are assigned a level when examined by a skin pathologist. The level is a guide to how deeply into the skin the melanoma has grown. The deeper the level, the higher the risk of the melanoma spreading to other parts of the body.

The melanoma stage is a description of how far the melanoma has spread.

Melanoma types

Melanomas are also categorised according to their appearance and growth pattern.⁷

Superficial spreading melanoma

Usually appears as a dark flat patch with irregular borders. It tends to grow outwards, which enables early detection by the patient. this is the most common form of melanoma, occurring in about 50% of cases.

Nodular melanoma

Nodular tends to appear as a raised lump, often with a firm consistency. Nodular melanomas tend to grow quickly and are more likely to have reached stage 3 or 4 by the time they are detected.8 Nodular melanomas make up 15% of cases.

Lentigo maligna melanoma

Lentigo maligna melanoma is a relatively slow-growing form of melanoma which resembles a large irregular freckle. It occurs most commonly in areas that have received sun exposure over many years and as such tend to occur on the face and head of older people. Lentigo maligna melanoma occurs in 10% of cases.⁷

Treatment of melanoma

All melanomas must be surgically removed with a clear margin around the edge. In most cases, melanoma in must be removed with a clear margin of at least 5mm but up to 20mm of normal skin around its outer edge.⁹

The initial excision biopsy is rarely this wide, so usually once a melanoma in situ is detected, a further excision must be performed to ensure wide clearance. If the melanoma is in a cosmetically sensitive area or if the function or movement of the area is likely to be affected, your skin cancer doctor may refer you to a plastic surgeon or the melanoma unit of a hospital for further treatment.

Learn more about excision and excision biopsy.

Follow-up: what happens next?

Further assessment

After a diagnosis of melanoma your doctor may perform an examination for signs that the melanoma has spread. This examination involves:

• Checking the lymph glands in the neck, armpits, groin and possibly behind the knees or elbows depending on the original site of the melanoma.
• Checking for enlargement of, or lumps in the liver or spleen.
• If it has not yet been performed, your doctor should check the entire body for melanomas and other skin cancers elsewhere.

Melanoma with a level greater than 1 potentially has a chance of spreading to other organs (although the risk is very low in level 2 disease). In addition to the stage, other factors may determine the likelihood of spread. These include:

• Overall thickness of the melanoma.
• Age of the patient.
• Presence of ulceration.
• Melanoma type (i.e. superficial spreading, nodular, lentigo maligna).
• Whether there is involvement of lymphatic or vascular systems.
• Whether there is evidence of rapid cell division.

Based on these factors, it’s possible to calculate the risk of a melanoma spreading to nearby lymph nodes.¹⁰ If the risk is greater than 5%, a lymph node biopsy may be considered. This procedure is usually carried out in a specialist melanoma unit.

Specialist referral

Your doctor may refer you to another doctor or health service for further treatment or assessment. For example:

• A plastic surgeon can perform a wider excision of the melanoma to achieve a good cosmetic outcome or preserve function of the affected area
• A public hospital melanoma unit can offer a team approach where surgeons, dermatologists, skin pathologists and other specialties are involved in your care. Your doctor may refer you to a public hospital melanoma unit for further treatment, for investigations such as lymph node biopsy. to get a second opinion on the initial skin pathologist’s report, or advice on future follow-up and treatment.

Can a melanoma return?

If the original melanoma returns, it is likely to be in the first 1-2 years after diagnosis.¹² People who have had a melanoma have an increased risk – as much as 5 to 10 fold – of developing a new melanoma in future. This increased risk persists lifelong.¹³

High risk patients

Some people have an especially high risk of developing further melanomas in future. These people include:

• People who have already had more than one melanoma.
• People with a strong family history of melanoma.

Mole mapping (total body photography) is sometimes recommended for people in these high-risk groups.¹⁴

Self-examination

Skin cancer self-examination is a very important part of ongoing care. In people with a previous melanoma, 75 per cent of new melanomas are self-detected by the patient.¹⁵ People with a history of melanoma should ideally check their own skin every 1-2 months.

Skin checks for your family

Melanoma tends to run in families. If you have had a melanoma, your first-degree relatives (children, sisters, brothers and parents) have an above-average chance of developing melanoma. They should check their own skin regularly and consider yearly skin checks by a doctor or nurse.

Learn more at the Melanoma Institute Australia website.

References

1. Victorian Cancer Registry 2023. Melanoma statistics and trends.
2. Australian Institute of Health and Welfare 2023. Risk of melanoma of the skin by age and over time, in Cancer data in Australia.
3. Cancer Australia 2024. Melanoma of the skin.
4. Jin Q, 2021. ABCDEFG of melanoma, in Dermnet NZ.
5. Menzies S, Guitera P, Soyer P et al. What is the role of sequential digital dermoscopy imaging in melanoma diagnosis? Clinical practice guidelines for the diagnosis and management of melanoma, 2018.
6. Cancer Australia 2019. Relative survival by stage at diagnosis (melanoma), in National cancer control indicators.
7. Melanoma Institute Australia 2024. Melanoma diagnosis.
8. Coroiu, A., Moran, C., Davine, J.A. et al. Patient-identified early clinical warning signs of nodular melanoma: a qualitative study. BMC Cancer 21, 371 (2021).
9. Sladden M, Nieweg O, Howle J et al. Updated evidence-based clinical practice guidelines for the diagnosis and management of melanoma: definitive excision margins for primary cutaneous melanoma. Medical Journal of Australia volume208 issue3, February 2018, pages 137-142, 2018.
10. Melanoma Institute Australia 2024. Sentinel node metastasis risk.
11. Thompson J, Scolyer R, Kefford R 2012. Melanoma: a management guide for GPs, in Australian Family Physician, vol. 41, no. 7. 
12. Barbour A, Guminski A, Liu W et al. Ideal settings, duration and frequency of follow-up for patients with melanoma. Clinical practice guidelines for the diagnosis and management of melanoma, 2019. 
13. Trotter S, Sroa N, Winkelmann R et al. A global review of melanoma follow-up guidelines. J Clin Aesthet Dermatol. 2013 Sep; 6(9): 18–26, 2013.
14. Mann G, Cust A, Damian D et al. What interventions have been shown to provide clinical benefit in those assessed to be at high risk of new primary melanoma? Clinical practice guidelines for the diagnosis and management of melanoma, 2018.
15. Barbour A, Guminski A, Liu W et al. Follow up after initial definitive treatment for each stage of melanoma. Clinical practice guidelines for the diagnosis and management of melanoma, 2018.