An Australian study comparing routine skin checks to patient-detected melanoma affirms earlier data, showing an increase in the detection of thinner, less-lethal lesions that may pose no immediate harm, according to experts. The prospective study also found no survival advantage to routine screening for melanoma, as the incidence of these cancers continues to rise in the United States. The American Cancer Society estimates that more than 100,000 Americans will be newly diagnosed with melanoma in 2021, compared with 76,380 confirmed cases just 5 years ago.
"The likelihood of dying (from melanoma) is no different between the two study groups," said Allan C. Halpern, MD, Chief of the Dermatology Service at Memorial Sloan Kettering Cancer Center. "But, the risk of dying from anything else is higher," he noted, as individuals getting regular skin checks are more likely to undergo testing by health professionals for other medical conditions.
Results of the study, involving 2,453 melanoma patients in New South Wales, appeared online in JAMA Dermatology (2021; doi:10.1001/jamadermatol.2021.3884). Researchers compared clinical and pathological data and mortality in the different cohorts, who were then followed out more than 10 years.
In an accompanying editorial, Halperm suggested it's time for a "reset" in how dermatologists screen for these lethal skin lesions, given not only the rise in thin disease that may not warrant biopsying, but also potential risks from overdiagnosis: unnecessary treatments and financial or psychological harm. He attributed the trend to increased screening pressure in the cancer community and the public's reaction to that pressure, despite a decline in melanoma mortality with improved treatments, such as checkpoint inhibitors, for advanced disease, in recent years.
"Unlike other cancers, "you don't need a fancy test to find it, you can look in the mirror and find it," Halpern said, with self-detection now having a similar impact to formal screening in perhaps fueling a rise in numbers.
However, because physicians still lack a clear molecular biomarker, which distinguishes aggressive melanomas from indolent cancers, he noted that they should focus only on patients at a high risk of dying, "until we come up with something so biologically clear-cut, we're willing to act on it."
High-mortality populations in melanoma include individuals with family histories, White men over age 50, and those with atypical moles or extensive sun damage. In comparison, though it undercuts the goal of equity in health care, Halpern said people of color and children have low rates of melanoma, and likely derive scant benefit from regular skin checks.
"We're NOT saying stop looking for melanoma," he stressed. "What we are saying is overdiagnosis is a problem in melanoma" even though researchers have not yet quantified the percentage of patients in whom this occurs. "But, we need to be extra cautious as we encourage early detection, especially in the population that has an expected benefit."
Reducing the risk to patients of overdiagnosis has emerged as a common research focus across the board in many cancers today, not just in melanoma, experts say. The United States Preventive Services Task Force gives an "A" rating to only two cancer screening tests-one for detecting colorectal cancer in individuals ages 50-75, the other for cervical cancer. The independent expert panel considers other cancer screening tests of moderate benefit and has not recommended for or against regular melanoma skin checks in average-risk individuals. But the panel has indicated targeted research among populations with the highest burden of this disease would be useful.
Stratifying risk in melanoma remains challenging, according to Clara Curiel-Lewandrowski, MD, Co-Director of the Skin Cancer Institute at the University of Arizona Cancer Center in Tucson. "Physicians have a good understanding of relative risk," she said, referring to risk factors, such as phenotypic appearance and sun-exposure behavior. "However, this approach is not sufficient as melanoma occurs in individuals who lack a high or even medium risk, based on these parameters."
And, as recently as 2012, Curiel noted that the Arizona Melanoma Task Force found that an estimated 75 percent of melanomas in Arizona had been underreported for more than a decade. The gap occurred, she said, because many dermatology providers in the state were unaware they had to report these cancers to the cancer registry, or found the reporting process itself a barrier. The issue, which has since been resolved, is reflected in the most recent SEER (Surveillance, Epidemiology, and End Results) data from the National Cancer Institute, which shows Arizona with its largest increasing incidence rate of melanoma in the past few years.
"We are seeing more invasive disease in Arizona and also in situ melanoma," Curiel said. "The question is what are the consequences of diagnosing more in-situ disease? We still don't know which ones will evolve into invasive disease. We do know that melanoma in situ develops very slowly," especially in one subtype (maligna melanoma), typically found in sun-exposed areas.
Given the lingering uncertainty, however, dermatologists usually excise every in situ lesion they detect, rather than risk missing a potentially deadly cancer-the lone exceptions: elderly patients or those unable to tolerate treatment for other health reasons, Curiel noted. Some of the perceived harms associated with increasing melanoma diagnosis also include increasing biopsy and diagnosis of non-melanoma skin cancers, which would be diagnosed and treated eventually as standard of care.
So, while she shares Halpern's concern about overdiagnosis, Curiel cited the need for further refining risk for effective screening approaches. "But, the technology we have now is powerful and should allow us to develop more robust and accurate biomarkers for melanoma" in the future, she noted.
Susan Jenks is a contributing writer.