Australia has the highest incidence rate of melanoma in the world. The majority of melanomas being caused is by sun exposure. The age standardized mortality rate is 6.2 per 100,000, with four people dying of melanoma each day. It also remains the number one cause of cancer-related deaths in Australians aged 20-39 years.
The thickness (Breslow depth) of melanoma at diagnosis remains the most important prognostic factor in melanoma survival. The 10-year survival rate for melanomas less than 1mm thick is 92%, and survival decreases with increasing thickness; 80% for melanoma 1-2mm, 63% for melanoma 2-4mm and only 50% for melanomas thicker than 4mm. It is therefore paramount that efforts are directed toward early detection of melanoma-
Melanomas often have no symptoms initially. The first noticeable sign will often be a change in an existing mole, or the appearance of a new spot.
Changes can include:
- A colour shift, or multiple colours forming within the mole
- An increase in the mole size
- An irregular border of the mole
- A raised area within the mole
- Itching or bleeding of the mole
Skin examination and detection
A thorough total body skin examination and dermoscopic examination with a hand-held device remains the cornerstone of melanoma diagnosis. In addition, several non-invasive imaging technologies have been developed over the past 10 years to aid in early melanoma detection. Among these are sequential digital dermoscopic imaging, total body photography and reflectance confocal microscopy. These are now considered current best practice in the assessment of melanocytic lesions, especially in high-risk patients. Regular self -examination of the skin is a well-established life saving measure. Using these strategies provides a comprehensive approach to early melanoma diagnosis and may lead to a reduction in melanoma mortality in the coming years.
The first step in the early detection of melanoma is a risk assessment when a person presents for skin examination, skin cancer check or skin lesion check. The individual risk assessment, together with examination findings, will guide important management decisions, such as the need for a biopsy, the frequency of follow-up, and determining if specialist referral is required.
Skin type, hair colour, eye colour and density of freckles are also important markers of increased risk of melanoma, as are large numbers of melanocytic naevi (moles) and atypical naevi (funny looking moles).
Personal history of melanoma is one of the strongest independent risk factors for melanoma, with a ninefold increase in the risk of developing melanoma compared with the general population. This risk remains elevated more than 20 years after the first melanoma.
A personal history of non-melanoma skin cancer is also associated with an increased risk of melanoma.
In addition to the traditionally recognised risk factors, epidemiological and genetic studies over the past decade have identified new risk factors for melanoma, including MC1R gene variants, childhood cancer history, immunosuppression, indoor tanning and Parkinson disease.
Using a risk assessment tool can be a simple and time efficient way of determining an individual’s melanoma risk. An Australia-specific risk assessment tool using data from the Victorian melanoma service and state cancer registries has been developed, which estimates five-year risk of melanoma. This is available online (https://www.alfredhealth.org.au/melanoma-risk-calculator/public) and free to use for health professionals and the general public.
A total body skin examination is essential in detecting melanoma in a person who presents for a routine skin cancer check or has a specific lesion of concern. Sites that are often overlooked during a total body skin examination and can lead to missing a melanoma, include the scalp, eyelids, inner canthi, behind the ears, inside the mouth, on or between the fingers and toes, and under the nails.
The ABCDE mnemonic of melanoma remains an important tool for detecting melanoma with the naked eye. The ABCDE stands for:
- Asymmetry (one half is not like the other half),
- Border (there are irregularities when the outer border is traced),
- Colour (there are multiple colours),
- Diameter greater than 6mm, and
- Evolution (there is change over time).
DERMOSCOPY is a non-invasive technique that uses lens magnification to visualise epidermal and dermal structures that are not normally visible to the naked eye. The use of dermoscopy with appropriate training has been shown to greatly increase the sensitivity of melanoma diagnosis.
SDDI involves taking several dermoscopic photographs of a melanocytic nevus (mole) over a period of time to detect changes. This modality can be used in two different ways, for short-term or long-term monitoring.
Short-term serial digital dermoscopic imaging is used for melanocytic lesions with an atypical clinical or dermoscopic feature (for example, eccentric pigmentation) to see if they are stable or dynamic. A baseline dermoscopic photograph is taken and the lesion is reimaged several months later. If there are any changes, the lesion is excised to obtain diagnostic verification. Long-term monitoring is done over a longer period, with twelve-month intervals or more, and includes a greater number, or all, of the patient’s naevi. Long-term SDDI is usually performed together with total body photography to detect changes in high-risk patients.
Total Body Photography
Total body photography results in high-resolution electronic images of the body showing the patient’s moles. The aim is to document the size, location and shape of all the moles on the individual’s body so that changes can be detected over time by comparing subsequent photographs.
Total body photography is also useful in avoiding unnecessary biopsy in suspicious, but stable lesions. It has also been shown to be helpful in detecting non-melanoma skin cancers.
The photos can be kept by the patient and be used at home, either during a routine self-examination of the skin or on detection of a new or changing lesion. The drawbacks of total body photography include the associated cost and increase in the time taken for a total body skin examination. However, this may be justifiable in high-risk individuals, such as those with increased numbers of moles, atypical moles and a personal or family history of melanoma.
This service is available at Sinclair Dermatology through our 3D whole body Vectra WB360 imaging system.
Up to 75% of melanomas are detected by patients, or their spouses, friends or family members. Regular self-examination has been shown to detect thinner melanomas, reduce the risk of secondary melanoma and advanced disease, and to reduce the melanoma related mortality by 63%. It is important that patients receive training on how to perform this examination, along with instructions on its frequency.
Patients should encourage their partner to assist them or to use mirrors to examine difficult areas, such as the back. Melanoma patients who are trained to perform self-examination with their partner’s help are very good at detecting suspicious lesions with a high rate of correspondence to that of the examining dermatologist.