They were hailed as a breakthrough in the battle against skin cancers, but now, researchers are warning against the use of smartphone apps to detect melanomas.

The British Medical Journal has published a review of six algorithm-based AI apps, and found they cannot be relied on.

"Our review found poor and variable performance of algorithm-based smartphone apps, which indicates that these apps have not yet shown sufficient promise to recommend their use," wrote the authors, from the universities of Birmingham and Nottingham in the United Kingdom.

Medical Director of the Cancer Society Dr Chris Jackson told Heather du Plessis-Allan that the study shows that some of these apps failed to detect any melanomas at all. 

"Not all apps are created equally. There are some apps where you can take a photo of your suspicious mole and it will get sent off to a qualified skin specialist."

He says that the area is highly unreliable and unregulated. Factors such as lighting condition and how far away your phone is from the mole has an impact. 

However, Dr Jackson says that we have to accept that AI will be an important part of medical diagnosis in the future. 

"Right now, the technology is just not there."