Skin cancer affects about one in two Australians––and not just fair-skinned, blue-eyed blonds, outdoor workers or people with a family history—says Associate Professor Robyn Saw, Head of the Melanoma and Surgical Oncology Department at Royal Prince Alfred Hospital and Surgical Oncologist with Melanoma institute Australia.

Here are some key ‘tips and traps’ to keep in mind when managing skin cancer in general practice.

A melanoma doesn’t always look like a melanoma

Melanoma is the third most common type of cancer in Australia. While typically pigmented, 20% are amelanotic and “don’t look like the classical melanoma,” she says.

Some can simply look like a plaque of pink tissue or a vague brown pigment. Melanoma can also occur in scar tissue.

Take a careful history

Sixty per cent of melanomas arise in normal skin and it’s important to listen to patients if they present with a concern, says Associate Professor Saw.

If a patient presents with a new or changing lesion, “ask them all about it,” she emphasises.

While you can reassure them if you’re certain about the diagnosis, she stresses the importance of follow-up, biopsy and referral if there’s any uncertainty at all.

“The misdiagnosis of melanoma is one of the most common causes for malpractice litigation,” she notes.

Examine the lesion

“Have a feel of it. Is it hard? Is it raised over the skin? Consider taking a photograph, and when you bring the patient back, if you think it’s benign, take another photograph and compare them.”

Learning to use a dermatoscope is essential to work out what the lesion is, she adds.

There are two types of dermatoscope—polarised and contact––and you can toggle between these functions on most modern ones. Polarised light allows you to see blood vessels in lesions.

You can take sequential dermatoscopic photographs to monitor lesions.

Do a full skin check

“Don’t just examine the lesion that they came with. Have a look at them generally,” Associate Professor Saw says.

She marks the lesion and anything else of importance on a skin-body diagram.

“The main thing is to be suspicious,” she adds. “Don’t ignore anything.”

Biopsy tips

Ideally, take out the whole lesion with a two-millimetre clearance.

“That gives the pathologist enough tissue to make a good diagnosis,” she says.

A complete excision may not be possible if the lesion is large or on somewhere like the face. In this case, do a partial biopsy, Associate Professor Saw says.

This could be:

• a shave biopsy – make sure it’s deep enough and large enough to provide adequate information if the patient requires melanoma treatment– the depth is important to determine an accurate prognosis and appropriate treatment
• an incisional biopsy – which should be taken from the middle of the lesion (no need to include normal skin)
• a punch biopsy (at least a 3-4mm punch).

“Don’t do an unusual flap or don’t take risks in terms of trying to achieve a complete excision biopsy if you can’t do it,” she adds. “Do a partial biopsy. Do it the right way.”

Assess the nodes

It’s important to clinically assess the draining node fields, Associate Professor Saw says.

Sentinel node biopsy may be necessary if:

• they have a melanoma that’s greater than 1 mm thick, or 0.8 to 1 mm thick with adverse features

• the Melanoma Institute Australia’s Sentinel Node Metastasis Risk Prediction Tool score is greater than 5%.

“Six to 15%, discuss a sentinel node biopsy. If greater than 15%, they should probably undergo a sentinel node biopsy.”

When to refer

She suggests referring to a skin cancer oncologist, dermatologist, or plastic surgeon if:

• you’re not sure what the lesion is and have any concerns about biopsying it
• the lesion is in a difficult area or margins are hard to identify
• the patient has a primary melanoma and the wide excision is difficult
• a discussion about sentinel node biopsy is necessary.

Find out more

Melanoma Institute Australia | Education portal