Early detection of skin cancer

This position statement is endorsed by the Australasian College of Dermatologists

Key Messages

• Survival from melanoma is strongly associated with depth of invasion; deeper and thicker melanomas are more likely to metastasise and be more difficult to treat. Thus, early detection is important.
• The majority of melanomas are detected by patients themselves or their partners. However, melanomas detected by doctors tend to be thinner.
• Cancer Council Australia encourages people to become familiar with their skin, including skin not normally exposed to the sun, and consult a doctor if they notice any change in shape, colour or size of a lesion, or the development of a new lesion.

Recommendations

• Cancer Council Australia recommends that people consult their doctor if they notice any changes to their skin. Full skin examinations supported by total body photography and dermoscopy are also recommended every 6 months for individuals at high risk.
• Skin examinations conducted by a doctor, using dermoscopy, are recommended for the early detection of skin cancer. Doctors examining lesions to detect skin cancer should be trained in and use dermoscopy.
• Cancer Council Australia does not recommend the use of smartphone applications by consumers to self-diagnose skin cancer including melanoma.
• Population-based screening is not recommended for melanoma or other skin cancers due to insufficient evidence that it reduces mortality.

Background

Skin cancers are named after the skin cell that the cancer develops from – melanoma, basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Potentially, skin cancer is almost totally preventable as the majority of Australian cases are caused by exposure to excess ultraviolet radiation. Melanoma is the least common skin cancer but it is the most dangerous.^[1] In 2015, 13,694 new cases of melanoma were diagnosed with 1,498 deaths in the same year.^[2] Keratinocyte cancers (KC) is far less likely to be life-threatening than melanoma, with around 400 times the number of cases but only a third of the number of deaths. In 2016, there were 679 deaths due to KC.^[2]

Skin examinations for early detection of melanoma

Regular skin self-examinations should be conducted by individuals so they are more familiar with their skin and can consult a doctor if they notice changes to lesions. As some lesions are not easily visible during a skin self-examination,^[3] individuals should ask others to check difficult-to-see areas such as their back, scalp and the back of the neck.

Cancer Council Australia recommends people see their doctor if they notice a new spot or changes in size, shape or colour of an existing spot, for clinical skin examinations for the early detection of melanoma. Australian studies have shown an association between clinical skin examinations by a doctor and a lower risk of being diagnosed with a thicker melanoma.^[4][5] Thinner lesions are associated with decreased risk of death^[6] and better prognosis.^[7]

Aids to clinical diagnosis of melanoma

The use of dermoscopy by experienced clinicians has been found to increase diagnostic accuracy.^[8] Dermoscopy (surface microscopy, dermatoscopy, epiluminescence microscopy) uses a hand-held magnifying device to improve visualisation of diagnostic features of pigmented and non-pigmented skin lesions that cannot be seen with the naked eye.^[9] Studies in the dermatologist setting have shown a reduction in rates of excisions of benign lesions associated with use of dermoscopy.^[10][11] In the general practice setting, studies have shown improvements in sensitivity for melanoma diagnosis for clinicians who have experience in the use of dermoscopy.^{[12][13][14][15][16]} It is recommended that clinicians who examine pigmented and non-pigmented skin lesions for the purpose of detecting skin cancer be trained in and use dermoscopy.^[9]

Total body photography is an additional aid used particularly for individuals at high risk of melanoma such as those with a high naevus count or multiple dysplastic naevi.^{[17][18][19][20][21]} While no randomised-controlled trials have been undertaken, more recent studies have confirmed that the use of total body photography detects early stage melanoma^[22][23] and has lower biopsy rates in individuals at high risk of melanoma.^[22] Further technological advancements have led to research being conducted in the area of 3D digital imaging.

Australian clinical practice guidelines recommend the use of short-term sequential digital dermoscopic imaging to assess individual melanocytic lesions of concern that lack dermoscopic features of melanoma for patients at average risk.^[9] For high risk patients, long-term sequential digital dermoscopic imaging should be used instead.^[9] Furthermore, routine use of automated instruments has not been recommended for clinical diagnosis of primary melanoma.^[9]

Skin cancer detection apps

In recent years, there has been a rise in smartphone applications for use by consumers for the early detection of melanoma. Research has shown that such applications are generally inaccurate in diagnosing melanoma and should not be used by consumers to substitute a skin examination by a doctor.^[24][25] Cancer Council Australia does not recommend the use of smartphone applications by consumers to self-diagnose skin cancer.

Population-based screening for skin cancer

The aim of population-based screening programs is to reduce mortality through early detection. In Australia, there is no formal population screening program for melanoma. Observational studies have shown the benefit of screening for melanoma,^[4][5][26] however due to lack of high level evidence showing a reduction in mortality from melanoma, population screening programs for melanoma are not recommended.^[27] For KC, as the majority of cases are not life-threatening or serious enough to cause long term illness population-based screening is not recommended.

While screening is not recommended on a population basis, for people at high risk of developing skin cancer, there is evidence to suggest opportunistic screening by general practitioners may be beneficial. Other individuals should conduct skin self-examinations and consult their doctor if there are changes to their lesions.

Early detection in high risk groups

People at an increased and high risk for skin cancer include those with:

• Fair skin, a tendency to burn rather than tan, freckles, light eye colour, light or red hair colour;
• Increased numbers of unusual moles (dysplastic naevi);
• Depressed immune systems (risk factor for SCC);
• A family history of melanoma in a first degree relative and
• Previous melanoma or KC.

The Royal Australian College of General Practitioners recommends that those at increased risk of skin cancer should be offered opportunistic clinical skin examinations.^[28] Individuals at a higher risk of skin cancer should undergo clinical skin examinations every 6-12 months, with or without photography, and be encouraged to conduct regular skin self-examinations.^[28]

Cancer Council Australia recommends individuals at high risk of melanoma and their partners should be educated to recognise and document lesions suspicious of melanoma. These individuals should see their doctor for 6-monthly full skin examination supported by total body photography and dermoscopy.^[9]

Position statement details

This position statement was developed by Cancer Council Australia's National Skin Cancer Committee and endorsed by Cancer Council Australia's principal Public Health Committee. It was published in January 2019.

For further information

Cancer Council Australia – http://www.cancer.org.au

Cancer Council Helpline – 13 11 20

The Australasian College of Dermatologists – http://www.dermcoll.asn.au

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