Skin cancer screening

Dr. LeachmanData-driven screening guidelines for skin cancer have been published electronically, in reaction to the U.S. Preventive Services Task Force’s 2016 draft recommendation statement on skin cancer screening.

The task force reviews all literature to determine if screening is important for a given medical condition, for which it deemed there was insufficient data to support or not support skin cancer screening.

“The task force does recommend that individuals at risk for skin cancer should be screened, but did not go into details about what constitutes a ‘high-enough’ risk to warrant screening,” says Sancy Leachman, M.D., Ph.D., a professor and chair of dermatology at Oregon Health and Science University in Portland, who is principal author of the electronically published guidelines.

Dr. Leachman blames this oversight in part on dermatology itself.

“We, as a field, have not published enough about data-driven screening guidelines for sub-populations of patients at higher risk for skin cancer,” Dr. Leachman tells Dermatology Times.

The team of melanoma experts compared the level of risk for known melanoma risk factors to the level of risk for other medical indications that have been sanctioned by the task force as deserving of screening.

“Instead of focusing on whether there is literature confirming that primary-care physician (PCP)-based skin cancer screening of a general population is helpful, we wanted to apply a very systematic and reproducible approach for recommending which sub-populations of high-risk patients should be screened,” Dr. Leachman says. “Our paper defines data-based risk categories that are in complete alignment with the task force guidelines for other diseases.”

Dr. Leachman says that none of the group’s proposed skin cancer screening guidelines should come as a surprise to dermatologists or other melanoma experts.

“The guidelines likely reinforce what dermatologists are already using as their standard of care,” she says. “But the guidelines may be somewhat surprising to primary-care providers who do not think about skin cancer screening all the time.”

The newly proposed guidelines recommend that adults between the ages of 35 and 75 be screened at least annually with a total body skin examination, if they have one or more of the following risk factors: personal history, family history, certain physical features and ultraviolet radiation (UVR) overexposure.

For personal history, “it is important to identify what has happened in that person’s medical history that makes them more susceptible to melanoma,” Dr. Leachman says. This includes a history of melanoma in themselves or having signs of severe photodamage.

For photodamage, the patient may have a precancer of the nonmelanoma type or a nonmelanoma type skin cancer. “This indicates that the patient’s skin is vulnerable to developing skin cancer and, based on epidemiological studies, these patients are also at higher risk for acquiring melanoma,” Dr. Leachman says.

Two less common features that can arise in a personal history are carrying a genetic mutation (in CDKN2A or other high-penetrance gene) and being immunocompromised. “As we evolve in medicine with a lot of different kinds of transplants and immunosuppressive therapies, people are becoming more and more at risk of immunocompromise-related skin cancer,” Dr. Leachman says.

For family history, any patient with one of more family members with melanoma is at risk. “Your personal risk for melanoma also increases, depending on how many blood relatives in the same family line have had melanoma or other related cancers - the more blood relatives with melanoma, the more risk,” Dr. Leachman says.

Physical features that place a patient at increased risk of melanoma are light skin (Fitzpatrick I-III), blonde or red hair, greater than 40 total nevi, two or more atypical nevi, numerous freckles and severely sun damaged skin.

“It does not take a rocket scientist, or a dermatologist, to know when there are physical signs of severe photodamage on a person’s skin,” Dr. Leachman says. “This usually happens because the patient has a skin type that is particularly vulnerable to UV radiation.”

UVR overexposure entails a history of blistering or peeling sunburns, or a history of indoor tanning.

“We have a large group of people who have tanning-salon exposure that do not really think of themselves as having been outside,” Dr. Leachman says. “There are also a lot of doctors who do not realize how prevalent tanning is.”

A dermatologist may ask the patient if they have had any blistering sunburns. “Because the patient has only gotten their burns during a tanning-salon episode, they do not say they had a sunburn, because they do not consider it the same,” Dr. Leachman explains. “Therefore, the doctor needs to check on all sources of UV radiation exposure.”

Dr. Leachman says some people will argue that there is already sufficient data to recommend screening for melanoma, while other people believe that this type of data is self-evident and should not require a formalized prospective randomized trial to prove.

The kind of data required by the task force to prove sufficiency for a recommendation “is highly unlikely to happen in the case of melanoma,” Dr. Leachman says. “Not only is it cost-prohibitive to perform this type of study on a general population in a primary-care setting, but designing a randomized control arm that is not screened would be difficult. Many dermatologists screen as part of what we consider to be standard of care. It could be considered unethical to decline to screen a high-risk individual.”

Furthermore, it would take thousands and thousands of cases, costing an enormous amount of money, “to prove that we have a reasonable screening process in place,” Dr. Leachman says.

Dr. Leachman envisions her paper as just the first step in refining even further the vulnerable population for skin cancer. “It would be great if this sparked a bigger conversation across the fields of dermatology, melanoma and primary care. Are these reasonable guidelines? Let me know!” ƒ

Disclosure: Dr. Leachman has been a medical advisor for Myriad Genetic Laboratories and Castle Biosciences.