- Nearly 15,000 Britons are diagnosed with dangerous skin cancer each year
- The cancer generally appears in existing moles, but it can be hard to spot
- By using ‘fractal geometry’, a new Dutch app looks for changes in the skin
You can now get mobile phone apps that claim to help diagnose everything from asthma to hearing loss.
And while you might quite rightly be sceptical about whether these can be a substitute for seeing a doctor, when it comes to spotting potentially cancerous moles, some apps may be worth using.
Nearly 15,000 Britons a year are diagnosed with malignant melanoma, the most dangerous form of skin cancer. But if it’s caught early, the chances of survival are very good.
The cancer generally appears as changes to existing moles, but it can be hard to distinguish dangerous moles from harmless ones.
While you might quite rightly be sceptical about whether your smartphone can be a substitute for seeing a doctor, it can be useful in spotting potentially cancerous moles
Until recently, this could only be done by a skilled dermatologist using high-tech equipment such as a dermatoscope — which can magnify mole images ten times and identify how far into the body the mole has penetrated, a sign of how aggressive they are.
But in recent years there has been an explosion of cheap mobile phone apps claiming to help users detect the danger signs early.
Some simply allow users to store images of their moles, taken with the phone’s camera, so they can track changes that might indicate cancer is present.
Others use complex algorithms based on thousands of stored images to calculate the likelihood that a mole is becoming cancerous — then issuing a colour-coded alert to indicate how serious it may be.
Next week, a new Channel 4 programme looks at whether one app in particular — SkinVision — can help spot potentially cancerous moles.
Developed in 2013 by dermatologists in Holland, SkinVision is one of dozens of mole apps available to download, at a cost of £2.99 (plus a £2.99 per month subscription fee).
The app uses a technique called fractal geometry, which looks for patterns in the outlines and dimensions of a mole that make it more likely to be malignant. It then classes it as high, medium or low risk.
Healthy moles are fairly symmetrical in shape, so any irregularity could suggest it is harmful.
A normal mole also has a smooth, consistent edge, whereas a melanoma is more likely to have a jagged, irregular outline.
Also, non-cancerous moles are usually one colour whereas a melanoma is made up of multiple shades.
Healthy moles are fairly symmetrical in shape, so any irregularity could suggest it is harmful
A SkinVision high-risk alert means it must be examined by a specialist immediately; medium, that it needs to be tracked for changes in size, shape and colour; and low, that no immediate action in needed.
So does it actually work?
Consultant dermatologist Dr Emma Wedgeworth, who used the app to assess volunteers’ moles in the Channel 4 programme, says it appears to be one of the few skin cancer apps with good research evidence behind it.
She points to a study in the Journal of the European Academy of Dermatology and Venereology in 2015 which found SkinVision was accurate at detecting melanoma, although not as good as a dermatologist.
It was used to scan 195 skin images and correctly diagnosed 73 per cent of those that were cancerous. It also correctly identified 83 per cent of those that were not cancerous.
A SkinVision high-risk alert means it must be examined by a specialist immediately
But doctors shown the same images correctly identified 88 per cent of cancers and were able to pick 97 per cent of those that were not malignant.
‘Fractal geometry technology is far from perfect,’ says Dr Wedgeworth.
‘But I do think it’s a good idea for patients to use apps that allow them to store images so they can monitor changes in moles, or even show their GP if they are concerned.’
So how can you tell if the app you have chosen — from the hundreds available — is safe and effective?
Last year, the Medicines and Healthcare Products Regulatory Agency (MHRA) ruled that any app which claims to help diagnose a condition should be judged as a medical device and must comply with EU safety and performance standards.
That means the CE mark — which shows it meets those EU safety standards — must be displayed on the app or the developer’s website.
And it doesn’t just apply to skin cancer apps, says the MHRA.
A statement on its website says: ‘Many apps on the market are classified as medical devices. These gather data from the person or a diagnostic device, such as diet, heartbeat, or blood glucose levels and then analyse and interpret the data to make a diagnosis, prescribe a medicine, or recommend treatment.
‘Apps that give incorrect diagnoses or prescribe inappropriate treatments may have severe, potentially life-threatening consequences.’
The Royal College of Physicians is also concerned. Last year it warned members: ‘If you are using an app that should have a CE mark, but it is missing, you are leaving yourself open to problems and possible litigation.’
But there is no central database of CE-approved apps. Furthermore, apps that simply record images (rather than attempt a diagnosis) do not need CE approval.
SkinVision claims to be the first and only skin cancer app that has completed the approval process.
The app uses a technique called fractal geometry, which looks for patterns in the outlines and dimensions of a mole that make it more likely to be malignant
Others aren’t doing so well. In 2015, skin cancer apps MelApp and Mole Detective were forced to abandon claims they could detect melanoma, after a probe by the U.S. Federal Trade Commission found insufficient evidence to support them.
A 2013 University of Pittsburgh study found three out of four unnamed skin cancer apps wrongly classified 30 per cent of cancerous growths as harmless.
Dr Anjali Mahto, from the British Skin Foundation, warns apps need to be treated with caution.
She says: ‘Most of those used for melanoma detection have not been validated for accuracy… There is no substitute for a full skin examination by a dermatologist.’
Be Your Own Doctor, Channel 4, 8.30pm, Monday, October 24