Identifying Skin Cancers

For UV Awareness Month, Dr Paul Charlson shows how to spot potentially suspicious lesions

Skin lesions are a common concern among patients and clinics will often be asked to remove them. Sometimes, patients will not mention them, as their agenda is with other signs of ageing, but the observant clinician will spot potentially suspicious lesions. It is important to make a diagnosis, or at least, recognise that the lesion might be concerning, and refer elsewhere. This is preferable to lasering, freezing or removing a lesion without histology.

Photo-aged patients often have skin cancers or pre-cancerous lesions, as well as rhytids. It is therefore important to be alert to their presence.

In my experience, the more skin lesions you see, the more you realise the difficulty of diagnosis without histology. However, there are certain characteristics of lesions that you can observe and explore with the patient which might alert you to potential skin cancers.

Most skin cancers are a result of photo-damage, and skin ageing occurs mainly because of photo-damage. There are three main forms of skin cancer: basal cell carcinoma (BCC), squamous cell carcinoma (SCC)and melanoma.

BCCs are common in Caucasians and the incidence is rising.1 These lesions can be typical (a persistent slowly growing pearly lump) but they can also be pinkish patches or appear in a variety of guises with pigmented lesions being quite frequent.

Two websites I find useful to illustrate skin cancers are the Primary Care Dermatology Society (pcds.org) and Dermnet NZ (dermnetnz.org); both have lots of diagnostic help and photographs.

BASAL CELL CARCINOMA

So, how might you recognise a BCC? The key is to be alert to their existence. If a patient asks about a lump, what should you do?

TIP 1: Take a proper history – Ask about the lesion, how long have they had it? Has it got bigger? Any lesion that has not disappeared in three months has to be regarded as at least suspicious. If a lesion is getting bigger, then it is of concern. Has the patient had a skin cancer before? If they have then this suggests photo-damage and a greater likelihood of skin cancer.

TIP 2: What are the characteristics of the patient’s skin? – Do they have fairskin? Type 1 or2 Fitzpatrick scale is fair. The arpansa.gov.au site has a useful section on deciding what type of skin yourpatient has.

Where is the lesion? Common sites are sun exposed face, neck, décolletage, ears, hands, forearms, and lower legs in women. Look for signs of photo-ageing. A fair skinned patient with a persistent lump which is slowly enlarging over several months or even years is likely to be a BCC. While BCCs are commoner in older people they do occur in younger patients.

TIP 3: Examine the patient – This means asking them to take some clothes off. A full examination of the skin means more than taking a cursory look at lesion and the surrounding area. You need to examine all the skin. BCCs are often multiple. Pick the lesion up if it has substance and is hard as this may well indicate a BCC. Similarly, if it is a flat plaque, stretch it and look at edge to ascertain if it is raised. This is called a 'whipcord edge' and is characteristic of superficial BCC. Most BCCs are nodular and have a pearly edge and sometimes ulcerated centre. If you use your phone camera to take a picture and enlarge it you can often see blood vessels running through the lesion like tree branches and dark clouds of pigment these are characteristic of BCC. Sometimes a BCC can arise in old scars, so be aware of these too. Training in dermoscopy is useful and there are several courses available.

MALIGNANT MELANOMA

The most dangerous skin cancer is malignant melanoma. There are around 16,000 new cases of melanoma every year in UK, according to Cancer Research UK, and around 86% of these are preventable by effective use of sun block especially at a young age. 2 Melanoma causes over 2,000 deaths per year in UK and early diagnosis affects prognosis. One in 36 UK males will have a melanoma during their life so it is not rare.

Melanomas are relatedto sun damage and commonerin Caucasians. About athird occurinunder50s, placingthem inthetypicaldemographic of manyaesthetic clinic's clientele. These lesions can betypically pigmented butvaryconsiderablyintheircharacteristics. Asignificant proportion are not pigmented, often intheform ofraised, pinknodules. Diagnosis, even in expert hands, can be difficult, which is why the proliferation of clinics removing moles without histology is very dangerous.

TIP 4: Take a good history – Most melanomas occur out of the blue, but about 25% occur out of pre-existing moles. Ask about the “mole”, how long has it been there and has it changed. Generally, melanomas grow over a few months but in my experience patients are frequently inaccurate about how long something has been there and whether it has grown.

TIP 5: Use the ABCDEFG3 rule –

A = Asymmetry: The two halves of the mole look different in shape and/or colour
B = Border: Look around the edge of the mole. Melanoma will often have an irregular, jagged, notched or blurred border
C = Colour: Several different colours or shades of colour, or a single colour that is different to other moles
D = Dimensions (changing size): Melanoma can spread outwards as a flat lesion, it can grow upwards as a hard lump and some do both
E = Elevation
F = Firmness to touch
G = Growth: Persistent growth for over one month.

LESIONS ARE MORE LIKELY TO BE BENIGN IF:

• They are growing gradually and symmetrically through puberty

• Brown moles that gradually become dome-shaped and soft/ wobbly to palpate, while maintaining a regular, symmetrical edge

• Brown moles that are one colour, or two colours where the colours are similar (e.g. two shades of brown) and where the pigment is arranged in a symmetrical fashion eg darker centre and lighter edge

• Itchy moles that are not changing and otherwise appear normal

• Moles that change rapidly (over a few days) becoming swollen, inflamed and crusty, and which then settle back down to their original appearancethese moles are likely to have been traumatised or become acutely infected

• Classical halo naevi in young patients.

TIP 6: Ignore TIP 5 – Unless you are trained in dermatology and the use of dermatoscope, do not manage the lesion yourself (even if you are a practised dermoscopist, you have to have a very low index of suspicion.) Refer the patient urgently to their GP and write to that GP immediately to inform them of your concerns.

TIP 7: Be suspicious – If you are tempted to remove, burn, or freeze a “mole”, ask yourself are you sure you know what the lesion is. There is no room for heroes here! In dermatology clinics, if we are suspicious, we remove the lesion for histology.

TIP 8: Don’t forget the nails – any new dark line in a nail or nail destruction, consider to be very suspicious.

TIP 9: Beware of the ‘ugly duckling’ – the mole that looks different from the other, as this could be a melanoma.

SQUAMOUS CELL CARCINOMA

SCCs are the other main type of skin cancer. These are often keratotic, warty looking lesions, occurring on sun exposed sites and are more frequent in older people. They grow in a few weeks to months. They are often tender to touch, with poorly demarcated induration which is adeep thickening of the skin. There is often inflammation which causes pain.

If you examine an SCC, it is firm. It can look like a nodule, a flat plaque, warty or ulcerated. Many SCCs look unpleasant and are painful and inflamed, but sometimes they can be fairly non-descript.

TIP 10: Refer to a GP – Any hard, inflamed, keratotic lesion that has grown over a few weeks or months, especially in an older, sun exposed individual, needs urgent referral to a GP with a letter, as this is likely to be an SCC.

This article is not intended to be exhaustive and designed to provide pointers to try to prevent clinicians missing skin cancers. Diagnosis is not easy, and mistakes are made by everyone dealing with the skin. Patients surprisingly ignore potentially serious lesions. Aesthetic clinics are seeing patients for skin problems, in particular, the results of photo-damage, so are going to see their share of skin cancers. If you spot one, you may save a life, or at least, prevent unpleasant and potentially disfiguring surgery.

DR PAUL CHARLSON

Dr Paul Charlson is a Royal College of General Practitioners-accredited general practitioner with extended rules (GPwER) in Dermatology and has worked in secondary referral NHS dermatology clinics for 15 years, in conjunction with consultant colleagues. He has worked in the field of aesthetics since 2002 and has clinics in Yorkshire and London. He is a member of the Primary Care Dermatology Society and associate member of the British Association of Dermatologists.