Overtreatment was one issue raised by a medical panel considering the benefits of full-body screening for skin cancer. (Marvin Joseph/The Washington Post)

A panel of medical experts said Tuesday that there’s too little evidence to determine whether routine full-body screening for skin cancer saves lives.

The federally appointed U.S. Preventive Services Task Force gave the visual screening a rating of “I” — meaning there was insufficient evidence for it to weigh the potential benefits against possible harms — for Americans of average risk. Yet its statement drew immediate pushback, with some physicians saying the outcome might encourage people to skip the awkward ritual of stripping down for an examination by their doctor for melanoma and other skin cancers.

“We make recommendations based on evidence only, not on expert opinion, and we put equal weight on the potential benefits and the harms,” said David Grossman, vice chairman of the task force and a senior investigator at Group Health Research Institute. “And we really don’t have good evidence on the benefits of screening.”

The panel’s statement, published in the Journal of the American Medical Association, got a thumbs down from the American Academy of Dermatology. “Dermatologists know that skin cancer screenings can save lives,” Abel Torres, the organization’s president, said in a statement.

“Melanoma accounts for the vast majority of skin cancer deaths, and non-melanoma skin cancers such as basal cell carcinoma and squamous cell carcinoma can have potentially devastating effects, including severe tissue loss, metastasis and death,” Torres said.

Skin cancer is the most common cancer in the United States. An estimated 3.3 million adults will be diagnosed this year with basal cell and squamous cell cancers, and more than 76,000 will learn they have melanoma, according to the American Cancer Society. While the first two are rarely fatal, melanoma will cause more than 10,000 deaths in 2016, the group said. Yet all forms are treatable if caught early.

An editorial accompanying the task force’s statement said the “I” rating does not mean there is not a benefit from screening but that more research is needed to determine if it should be recommended — and, if so, for whom. Grossman stressed that the statement doesn’t apply to people who have skin lesions or any other kind of suspicious growths or to those with an increased risk of cancer or a family history of the disease.

But unnecessary screening could lead to overtreatment, including unneeded biopsies with unwanted side effects, he noted. “If  you have a lot of lesions, a fair amount of scarring could occur,” he said.

And while it seems “intuitive” that full-body exams would result in cancer being caught early, Grossman said the research suggests that some doctors are much more adept than others at finding lesions.

The American Cancer Society doesn’t currently recommend annual skin exams by a health-care professional. It does recommend that Americans be familiar with the normal appearance of their skin.

In addition, said Robert Smith, the group’s vice president for cancer screening, individuals should take precautions against skin cancers by minimizing exposure to intense sun and ultraviolet radiation. The prime strategies are protective clothing, sunglasses that block UV rays and broad-spectrum sunscreen with an SPF of 30 or higher. Sunbathing and indoor tanning should be avoided, he said.

The task force’s statement didn't deal with self-examination for skin cancer, which it says will be handled in a separate recommendation in the future.

The panel is an independent group of national experts on prevention and evidence-based medicine whose recommendations are designed to provide guidance to primary-care doctors. It assigns each preventive service a letter grade — A, B, C, D or I — based on a review of the research. The task force, which receives no compensation for its work, says its recommendations apply only to people without symptoms of any specific disease.

The skin-cancer screening is the latest preventive service to be hotly debated among experts. Mammograms and prostate screening have been at the center of controversies for years, as physicians try to walk the line between effective screening and potential overtreatment.

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