Smartphone apps designed to detect skin cancer have been shown to be unreliable and could fool people into thinking a cancerous mole is benign, says new research published today.
And the Chicago researchers who tested the apps said people should not rely on them.
The University of Pittsburgh Medical Center study, published in Online First, found that three out of four of the apps said 30 per cent of cancerous skin lesions were of no concern.
Researchers used 60 images of melanomas and 128 benign skin lesions to test four different apps.
Of the 60 melanomas, 18 were incorrectly diagnosed as benign and one app only had a 6.8 per cent success rate of identifying melanoma.
Dr Anthony Tam, a skin specialist from Mt Eden Medical Centre in Auckland, said there was merit in the idea of the apps but the results of the study proved how they could be dangerous for users.
"False reassurance can lead to a delay in diagnosis and advancing of the tumour," he said.
One of the apps sent an image directly to a board-certified dermatologist for analysis, while the others used automated algorithms to analyse the images.
Tam said two of the most aggressive and deadly types of skin cancer were the nodular or amelanotic melanomas which were likely to be missed by the apps.
"These will fool many of the applications based on algorithms in that they are often very symmetrical in shape and often only one colour," he said.
He also said the apps didn't take into account "the ugly duckling sign" which was an important method to assess what the moles looked like around an individual lesion.
Dr Jan Pearson, the Cancer Society of NZ's Health Promotion Manager, said using apps as a diagnostic tool was not a good idea.
Pearson herself downloaded one app to try it and was concerned about people getting an incorrect diagnosis and going untreated.
"If you photograph a lesion one way and then the next time a different way, the readings might be different and so it's not accurate," she said.
"We certainly support monitoring, but self-monitoring using a device like this does give people a false sense that things might be ok when they aren't."
She said the apps did have general information about checking and protecting skin which was good for raising awareness.
"Hopefully people use them as an interest thing rather than relying on them," she said.
"What we would always advise is to know your own skin and check it, get someone to check the areas you can't see, and to go to your health professional about it just to be assured whether something is sinister or not."
There are more than 13,000 health care apps available and the mobile health app industry made an estimated $718 million worldwide, according to a recent report by Research2Guidance, a consulting firm.
The cost of the four apps in the study ranged from free to $5.29, a lot cheaper than a $50 doctor fee or $300 mole map, which Pearson said was why people might use them.
Tam suggested the convenience and low cost would not be worth the potentially life threatening tumour.
Skin cancer is the most common cancer in New Zealand, with Kiwis at a high risk of developing a skin cancer during their lifetime.
Should fluoride in water be the responsibility of central government?