The USPSTF reports that the evidence for screening for skin cancer is weak. Some dermatologists are concerned, saying that lack of evidence of benefit doesn't mean there is no benefit. What should a patient think or do?
The United States Preventive Services Task Force (USPSTF) is "an independent, volunteer panel of national experts in prevention and evidence-based medicine" whose role is to evaluate evidence related to clinical preventive services such as screenings. These recommendations are supposed to inform both primary care physicians and the public. The members of the panels are drawn from a variety of medical specialties, and they give their recommendations a letter grade — A,B,C,D or I, based on the strength of the evidence. They recently posted their latest recommendation in JAMA — on the utility of screening for skin cancer by visual inspection, and gave it the letter I, which means:
"The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of the service. Evidence is lacking, of poor quality, or conflicting, and the balance of benefits and harms cannot be determined."
Although the Task Force is essentially remaining neutral on the issue of whether screening for skin cancer is useful for detecting, preventing or minimizing mortality due to skin cancer, some caveats must be noted. First, their recommendation is only applicable to adults with no risk factors for skin cancer — that would include persons with no previous occurrences of such malignancies and no family history. Further, some experts have weighed in, expressing some concerns — including that patients and health care providers alike might assume that because the data don't show a benefit of screening, there is no benefit.
For example, in an editorial accompanying the USPSTF report, Drs. Hensin Tsao and Martin A. Weinstock, dermatologists from Massachusetts General Hospital in Boston and Brown University in Providence, RI, respectively make that point, saying "“insufficient evidence of benefit” is different from “evidence of no benefit”: the public, physicians, and the popular press should avoid this misinterpretation." They also make the point that while the current report is directed toward the individual with no risk factors, it has been widely acknowledged that certain types of skin lesions (multiple moles, e.g.) are risk factors for melanoma, the most dangerous type of skin cancer, the only way to detect them is by visual inspection.
Another editorial by dermatologists Susan M. Swetter, Alan C. Geller and Allan C. Halpern, from the VA in Palo Alto, the Harvard Chan School of Public Health in Boston and Memorial Sloan Cancer Center in New York, respectively, opine that dermatologists should foster collaborations with primary care physicians, whether or not the USPSTF advisory changes. In particular, they should focus on the demographics with the greatest propensity for melanoma (white males older than 50 and those with lower socioeconomic status), as well as the sites most likely to be at risk, such as the scalp and back.
Yet another editorial by dermatologists Vinayak K. Nahar, Jonathan E. Mayer and Jane M. Grant-Kels, MD from the University of Mississippi Medical Center in Jackson, Johns Hopkins Medical School, and the University of Connectticut Health Center in Farmington, expresses concerns about the USPSTF advice. These authors note that total body skin examination (TBSE) has been shown to be superior to examination of one patient-discovered lesion with respect to skin cancer detection. They also cited a study that "found that more than one-third of melanomas are detected as incidental lesions and would be missed without a TBSE." They also note that melanomas first detected by a physician are thinner than those detected by a patient — and thus less likely to have metastasized. They propose that perhaps screening should be focused on those at higher risk for developing melanoma — those with a history of severe sunburns, tanning, fair skin, or many nevi (moles).
Thus, while the USPSTF report indicated lack of evidence for the efficacy of screening, dermatological experts aren't totally in agreement. What is the patient supposed to make of this loggerhead? Basically, it is vital for a person to understand the importance of the characteristics that increase the risk of skin cancer, and take steps to minimize those that are modifiable (e.g., no indoor tanning). As our population ages, the likelihood that more skin cancers will occur will increase, so attention must be paid to those factors. And clearly, high-quality research is needed to clarify the benefits and risks of screening for skin cancer.