Malignant melanoma is often lethal, and its incidence in the United States has increased rapidly over the past 2 decades. Nonmelanoma skin cancer is seldom lethal, but, if advanced, can cause severe disfigurement and morbidity. Early detection and treatment of melanoma might reduce mortality, whereas early detection and treatment of nonmelanoma skin cancer might prevent major disfigurement and, to a lesser extent, prevent mortality. Current recommendations from professional societies regarding screening for skin cancer vary.
To examine published data on the effectiveness of screening for skin cancer by a primary care provider.
We searched the MEDLINE database for papers published from January 1994 to June 1999, using search terms for screening, physical examination, morbidity, and skin neoplasms. For information on accuracy of screening tests, we used the search terms sensitivity and specificity. We identified the most important studies from before 1994 from the second edition, and from high-quality reviews. We used reference lists and expert recommendations to locate additional articles.
Two reviewers independently reviewed a subset of 500 abstracts. After consistency was established, 1 reviewer reviewed the remaining abstracts. We included studies if they contained data on yield of screening, screening tests, risk factors, risk assessment, effectiveness of early detection, or cost effectiveness.
We abstracted the following descriptive information from full-text published studies of screening and recorded it in an electronic database: type of screening study, study design, setting, population, patient recruitment, screening test description, examiner, advertising targeted at high-risk groups or not targeted, reported risk factors of participants, and procedure for referrals. We also abstracted the yield-of-screening data, including probabilities and numbers of referrals, types of suspected skin cancers, biopsies, confirmed skin cancers, stages, and thickness of skin cancers. For studies that reported test performance, we recorded the definition of a suspicious lesion; the gold standard determination of disease; and the number of true-positive, false-positive, true-negative, and false-negative test results. When possible, we recorded positive predictive values, likelihood ratios, sensitivity, and specificity.
No randomized or case-control studies demonstrate that screening for melanoma reduces morbidity or mortality. Basal cell carcinoma and squamous cell carcinoma are common, but detection and treatment in the absence of formal screening is almost always curative. No controlled studies have shown that formal screening programs improve this already high cure rate. Although the efficacy of screening has not been established, the screening procedures themselves are noninvasive, and the follow-up test—skin biopsy—has low morbidity. Estimates of accuracy of screening are based on cross-sectional studies that suffer from workup bias. One prospective study tracked patients who had negative results to determine the number of patients who had false-negative results. In this study, the sensitivity of screening for skin cancer was 0.94 and specificity was 0.975. Several recent case-control studies confirm earlier evidence that patients who have atypical moles, many (>50) common moles, or both are at increased risk for melanoma. One well-done prospective study demonstrated that risk assessment by limited physical examination identified a relatively small (<10%) group of primary care patients for more thorough evaluation.
The quality of the evidence for routine screening by primary care providers for early detection of melanoma or nonmelanoma skin cancer ranged from poor to fair. Despite the lack of evidence, skin cancer screening, perhaps by means of a risk-assessment technique to identify high-risk patients who are seeing a physician for other reasons, is the most promising strategy for addressing the excess burden of disease in older adults.
