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Skin cancer: teaching our patients about sun protection

Thomas F Poyner
FRCP (Lond and Glasg) MRCGP
General Practitioner
Queens Park Medical Centre
Stockton-on-Tees
Hospital Practitioner/Honorary Lecturer University of Durham
E:Thomas.Poyner@gp-a81002. nhs.uk

Skin cancer causes significant morbidity and mortality. Sun exposure is a major factor, the nonmelanoma skin cancers tending to be associated more with cumulative damage, while melanomas are more associated with brief intense exposure. Only by reducing ultraviolet light (UV) exposure can we reduce the prevalence of skin cancer, and by early detection and treatment reduce the mortality from melanoma.
Solar radiation comes in two forms - UVB which produces burning, and UVA which causes ageing. Those most at risk of skin cancer are those white people who are blue-eyed and fair-skinned, who tend to burn rather than tan. The nonmelanoma skin cancers tend to occur in middle and old age. They are often found on sun-exposed sites such as the face and hands. Melanomas can affect a slightly younger group.
 
Basal cell carcinomas
Basal cell carcinomas (BCCs) are the most common skin malignancy - four times more common than squamous cell carcinomas. BCCs are usually found on the face, neck or back. If left untreated they continue to grow locally, but have a very low potential to spread.
BCCs have a translucent, pearly appearance with telangiectasia. They can appear nodular or cystic and go on to ulcerate in the centre producing a "rodent ulcer". BCCs can be pigmented, which can cause confusion between them and melanomas. The pigmentation is due to an excess of melanin, the lesions are usually nodular and tend not to go on to ulcerate.

[[nip12_fig1_33]]

A BCC (especially on the trunk) can present as a superficial spreading lesion with a raised rolled edge, best demonstrated by stretching the lesion. Morphoeic BCCs present as yellow, ill-defined plaques, that can look similar to a plaque of psoriasis.
There are a number of treatments for BCCs depending on the site, type and size of the lesion. One also has to consider the age, mobility and general health of the patient and what facilities are available locally. Treatments include: excision biopsy, curette and cautery, cryotherapy, radiotherapy and photodynamic therapy.
Difficult sites include the nasolabial folds and difficult lesions are morphoeic BCCs, because with these it is difficult to define the tumour margins. Mohs' micrographic surgery is becoming more available in specialist centres and gives excellent results for difficult cases. It involves samples being taken for histology during the operation, enabling checks to be made that the lesion is completely excised. It is more expensive and time- consuming than other treatments.

Actinic keratoses
Actinic keratoses present as rough, scaly lesions that are often more easily felt than seen. Favourite sites are the bald male scalp and the back of the hands. They are usually multiple. Twenty five per cent of actinic ­keratoses resolve spontaneously and the remainder have a low rate of malignant change. Those that do undergo malignant change into squamous cell carcinomas do not result in very aggressive tumours. Any thicker lesions, with induration or ulceration, should arouse suspicion of malignant change and need excision and a histological diagnosis. Treatments for actinic keratoses include: 5% fluorouracil cream, 3% diclofenac gel, cryotherapy, curettage and cautery, and photodynamic therapy.

[[nip12_fig2_33]]

Photodynamic therapy is a novel therapy for certain malignancies. So far it has been used to treat actinic keratoses and superficial and nodular BCCs. It requires the application of a special cream and a light source. A thin layer of a cream containing methylaminolevulinate is applied to the lesion and 5-10mm of the surrounding skin. This is then covered with an occlusive dressing for three hours. The dressing is then removed, the area cleaned with saline and the lesion exposed to red light.

Bowen's disease
Bowen's disease is a type of intraepidermal carcinoma that presents as red scaly patches, usually on the lower legs. It can resemble a plaque of psoriasis. Treatments include excision, curettage and cautery, and cryotherapy.

[[nip12_fig3_34]]

Squamous cell carcinomas
These are the second most frequent skin cancer. As well as solar radiation, squamous cell carcinomas can be related to immunosuppression, coal tar and radiotherapy. They can also arise from actinic keratoses, Bowen's disease and chronic ulcers. They can present as either a rapidly growing fleshy nodule or a crusted lesion. There is loss of the normal skin markings and they can bleed.
Squamous cell carcinomas are found on the face and back of hands in both sexes. For men common sites are the scalp and ears and for females the lower legs. Squamous cell carcinomas on the lip and ear tend to be more aggressive. The two-week rule for skin cancer referral applies to suspected squamous cell carcinoma and melanoma. Treatment is by excision.

[[nip12_fig4_34]]

Melanoma
Melanoma is less common than the other skin cancers. However, while curable if treated early, late ­presentation of thick lesions carries a poor prognosis. The risk of melanoma is increased by sunburn, especially in childhood. Those with fair hair and light coloured skin are most at risk. Risk factors include: a family history of melanoma, the presence of atypical moles (irregular shape and multicoloured), and having multiple moles. From 30% to 50% of melanomas develop from a pre-existing naevus - large, congenital giant navei ­especially carry an increased risk for melanoma.
When trying to diagnose melanoma one should inquire about any recent change in size, shape or colour of the lesion. Early detection can help save lives as the thicker the lesion at diagnosis the worse the prognosis. Hence the publicity, health education, two-week rules and pigmented lesion clinics.
Treatment of suspected melanoma is by excision biopsy. The excision margins depend on the depth of the tumour. When treating suspected skin cancer all samples need to go for histology and systems need to be in place to follow-up patients and results.

[[nip12_fig5_36]]

Superficial spreading melanoma is the most common type and the female leg is the most common site. The next most common is nodular melanoma, classically found on the back of males. Lentigo maligna are usually found on the face of elderly patients. They present as a brown or black macule, or a patch with an irregular border. Lentigo maligna can go on and develop areas of invasive, nodular malignant melanoma. Treatment is surgical; cryotherapy was a popular treatment until it was realised that although this may result in loss of pigment, it may not halt the potential to progress to malignancy.
Acral lentiginous melanomas are located at the extremities, eg, the palm of the hand, the sole of the foot or the nail bed. They can resemble a superficial spreading or nodular melanoma. Amelanotic melanomas can be difficult to diagnose and often carry a poor prognosis.
 
Prevention
When it comes to treating skin cancer, prevention is definitely better than cure and health education is the way forward. This requires awareness of the risks of solar radiation and advising on appropriate action. This necessitates changing people's attitudes, such as the idea that "tans are healthy".
Recreational sun exposure has increased with sunny continental holidays and the desire to have a tan. Sun avoidance should be encouraged, especially in the hours around midday when the UV is most intense. Not only are summer holidays a risk, but also skiing breaks. The thinner atmosphere at high altitudes and the extra light reflected from the snow can cause sunburn. Outdoor occupations also increase risk, as do hobbies such as gardening. Outdoor sports such as sailing, cricket and golf can result in sunburn and increased risk of melanoma. Schools, parks and institutions need to have shaded areas in playgrounds and recreational areas. Sunbeds and tanning booths are another source of UV light and are a major risk factor for skin cancer.
Clothing can help protect from solar damage. Clothing should be close weave - a simple test is to hold a garment up to the sun and see if it does not let light through. Hats can protect the scalp and wide brimmed ones help protect the face. To bring home the point just check how many elderly bald gardeners you see that have actinic keratoses.
Sunscreens can reduce the amount of solar radiation reaching the skin. High factor sunscreens (minimum SPF 15+) need to be applied before sun exposure and the application repeated every two to three hours. A total sun block stick (SPF 15+) can be used on the lips. However, patients should not completely rely on sunscreens, if they do, they may actually spend longer in the sun and reduce any benefit! Sunscreens tend to be underused and applied in insufficient amounts.
Healthcare in the UK needs to provide clear messages to the population to protect their skin and the skin of future generations from the physical and psychological scarring of skin cancer.

Resources
Department of Health
Referral Guidelines for Suspected Cancer
W:www.doh.gov.uk/pub/docs/doh/guidelines.pdf

Photocredit - Dr P Mazarri/James Stevenson/Karol Sikora/Science Photo Library