COMMENTARY

Head-to-Toe Skin Cancer Exam in Primary Care Does More Harm Than Good

Kenneth W. Lin, MD, MPH

Disclosures

November 17, 2022

Kenneth W. Lin, MD, MPH

Hi, everyone. I'm Dr Kenny Lin. I am a family physician and associate director of  the Lancaster General Hospital Family Medicine Residency, and I blog at Common Sense Family Doctor.

A significant portion of my practice consists of adult health maintenance visits. Acknowledging the never-ending debate about the value of general health checks in well persons, I still see these visits as opportunities to provide recommended immunizations, screening tests, and counseling on healthy lifestyle habits. I also perform a physical exam. Whether this exam should include a head-to-toe survey for skin cancer has long been uncertain.

The US Preventive Services Task Force (USPSTF) recently released a draft recommendation statement that reiterates previous assessments that there isn't enough evidence to judge whether screening for skin cancer in an average-risk patient without a history of cancer is beneficial. Nonetheless, many family physicians and general internists do full-body skin exams or refer patients to dermatologists to get them done. In the spirit of reevaluating established screening practices, I will make the case that skin cancer screening does more harm than good, so we should stop doing it.

Using data from the National Cancer Institute's Surveillance, Epidemiology, and End Results program, a research team demonstrated that the incidence of cutaneous melanoma has increased sixfold over the past 40 years, whereas the incidence of noncutaneous melanoma did not change. Sunburns and tanning beds can't explain this dramatic increase in skin cancers, they argued; instead, greater diagnostic scrutiny (more full-body skin exams), increasing use of skin biopsies, and falling pathologic thresholds for diagnosing melanoma are the most likely culprits. Because the melanoma mortality rate did not budge, it's likely that most of the additional skin cancers detected by screening did not require treatment and were overdiagnosed.

How can we conclude that more screening is driving more skin cancer diagnoses rather than some environmental risk factor? Several years ago, a national study found a correlation between the density of primary care physicians and increased risk for melanoma diagnosis: "Per 100,000 people, an additional 10 PCPs per county was associated with 1.62 additional cases of melanoma per year." These additional melanomas were overwhelmingly early-stage, with no associations with later-stage melanoma or melanoma deaths. A recent cross-sectional study confirmed that melanoma incidence in US counties rises as the supply of primary care physicians and dermatologists increases, whereas proxies of exposure to ultraviolet radiation had no association with melanoma incidence.

Granted, overdiagnosis occurs in screening for breast, lung, and prostate cancers too, and that doesn't mean those tests aren't worth doing if patients are adequately informed about this possible harm. Similarly, detecting "extra" melanomas through skin exams might be worthwhile if treating all of those early-stage lesions spared lives or lessened the morbidity associated with later-stage treatments. Unfortunately, the evidence suggests that doesn't happen. In a German study reviewed by the USPSTF, after the implementation of a national routine skin cancer screening program covered by health insurance, melanoma mortality went up, not down. Closer to home, a primary care-based skin cancer screening initiative at the University of Pittsburgh Medical Center found that after 5 years, screened patients were more likely to be diagnosed with thin melanomas but not less likely to be diagnosed with thicker ones, which an accompanying editorial observed is "a classic signature of overdiagnosis."

Don't misunderstand me: I am not encouraging my colleagues to disregard patients' concerns about changing moles or to look the other way if they happen to see a suspicious lesion in the process of performing a physical examination for other reasons. What I am saying is that the time it takes to do a thorough skin examination could be better spent on providing effective preventive services that do not subject patients to the inconvenience and risks of needless skin procedures.

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