Your Smartphone as Dermatologist: Fast, Cheap...and Often Wrong

We are often told that the best protection against melanoma skin cancer is staying out of the sun. But the other defense is detection. Spotted early, melanoma is easily treated. Found too late and it's potentially fatal.

This year, some seventy-three thousand Americans will be diagnosed with melanoma. The disease kills almost ten thousand of these people.

That's why doctors recommend that patients undergo frequent skin checks, especially for those who are prone to developing worrisome moles. Bryce Zaffarano, a 23 year-old physical therapy student in Denver, is one of these people. His first encounter with melanoma was when he was just 16-years-old, when he noticed a dark spot on his chest.

“It was concerning,” he says, “but I was like, okay, I’m destined,” — both his mother and uncle had been diagnosed with melanomas, and Zaffarano, like them, had spent most of his childhood in the sun.

The doctors removed his mole right away, catching it early enough. Now, Zaffarano visits the dermatologist every three months for an all-over body check, an appointment he has kept faithfully for the past seven years. He’s already had one more scare he was glad the doctors spotted right away: another melanoma, this time on his lower back.

But those who don't have an existing relationship with a dermatologist may face challenges booking an appointment. The average wait-time for a dermatologist across the country is over four weeks, up from just three weeks in 2009. In some cities, like Boston, the average wait is three months. 

Now, some companies are trying to capitalize on impatient patients, offering a fast-paced alternative to old-fashioned doctors: smartphones. Why wait months for an hour-long dermatologist appointment, if an app can do the job?

Missing the Obvious 

There are 39 mobile applications for Apple and Android platforms currently on the market that claim to diagnose or screen for melanoma using images of moles you take with your phone. Some use automated analysis of the photos, similar to popular apps like LeafSnap or MealSnap that use computer vision to identify plant species or food calories. Others claim photos are analyzed by licensed dermatologists.

Snapping photos of concerning spots and getting instant feedback may sound convenient but doctors warn about over-reliance on these apps. Laura Ferris, a dermatologist at the University of Pittsburgh, said she had heard of these dermatologist-impersonating apps, but didn’t think many people were actually using them -- until patients starting asking questions.

Ferris and two of her students decided to see if the apps worked. They tested four of the most popular apps on the market for accuracy using 188 images of skin lesions, of which 60 were melanomas, and asked the apps to diagnose them as benign or malignant. The results were troubling: three out of four of the apps misclassified 30 percent or more of melanomas as benign. The fourth app, which relied on a dermatologist analyzing the photos, was more accurate, but it cost $5 per lesion evaluated.

These photos were “very obvious melanomas,” Ferris says, but the team found that the computer couldn't recognize them.

Ferris says the inaccuracy of these apps is especially dangerous for people who feel they can’t afford the time and money to visit to the dermatologist. An incorrect diagnosis via an app would be dangerous for patients who need to get in to the doctor quickly.

In more recent years, other studies have questioned the legitimacy of mobile dermatology apps. A review published last month in the British Journal of Dermatology found that melanoma detection apps have potential but are largely inaccurate. The majority not been vetted by dermatologists, and make false promises.

“No tool is perfect [and] no drug is perfect. But people need to be able to make informed decisions,” Ferris says. “[These apps] need to have data to backup the claims that they’re making.” Right now, there's no watchdog organization that can prove to both doctors and patients that this data is accurate.

Wanted: A Mobile Health Watchdog 

This lack of clinical evidence is not unique to the so-called melanoma-detection apps. A 2013 paper in the Journal of Medical Internet Research found that of the approximately 295 cancer-focused (prevention, education, or diagnostic) apps on the market, very few had been evaluated by medical professionals. Likewise, a 2012 paper on colorectal smartphone apps found that nearly all the available apps lacked scientific or medical input.

The problem is that many health apps don’t have any more restrictions than dating or gaming apps. The FDA only regulates mobile apps that attach to a medical device, or that transform a mobile phone into a medical device.

The Federal Trade Commission has taken a more active role than the FDA in policing melanoma-finding smartphone apps. In February of this year, it challenged two companies, MelApp and Mole Detective, for making false advertising that they could diagnose melanoma accurately. The claim with MelApp was just settled in April, and and the company was fined over $17,000.

For now, it's largely up to consumers to decide whether an app developer can be trusted. Ferris warns that it's not enough to give these apps a stamp of approval just because they appear in the App Store.

A Tool for the Future?

The skeptical reception from dermatologists and researchers like Ferris doesn’t seem to have deterred app developers.

Professor Xiaojing Yuan, who studies computer vision in the engineering department at the University of Houston, is in the process of commercializing a fully-automated smartphone tool she’s developed to detect melanoma.

Yuan stresses that the app is a screening tool that informs patients whether or not they should worry about a mole -- and isn't intended to replace a doctor. “Diagnosis is a strong word,” she says.

But the tool is intended to help patients decide whether or not to visit the dermatologist, which is exactly the decision Ferris is worried about.

Yuan admits there are several challenges to using computer vision technology to screen for skin conditions: Melanomas can vary a lot, and the difference between healthy skin and cancerous tissue can be hard even for dermatologists to determine. Moreover, Yuan has to contend with the relative poor quality of smartphone photos as compared to those taken in a doctor’s office.

Challenges aside, Yuan claims her tool performs much better than those currently on the market — but she would never recommend that it replace dermatologists altogether. Not yet, at least.

Establishing a Connection

And although she’s skeptical of many of the apps she’s tested, Ferris is still excited about the potential of using technology in her practice.

She’s especially interested in the emerging field of "telemedicine" companies that use smartphones to connect dermatologists to patients in remote areas. Some of the other doctors in her practice are currently testing out telemedicine products.

What's most important for Ferris is establishing a real connection between a human doctor and patient -- both in the diagnosis and in the follow-up. This rings true for Zaffarano.

“When there have been problems, they [dermatologists] have taken immediate action,” he said. It’s inconvenient to spend 45 minutes naked in the doctor’s office every three months, but he’s too skeptical of these smartphone apps to trust them with his life.