Skin Cancer: Screening --Asymptomatic adults


General

Grade: I 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. Read the clinical considerations section of USPSTF Recommendation Statement. If the service is offered, patients should understand the uncertainty about the balance of benefits and harms.

Specific Recommendations

The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of visual skin examination by a clinician to screen for skin cancer in adults.

Frequency of Service

No information available.

Risk Factor Information

Skin cancer of any type occurs more commonly in men than in women and among persons with a fair complexion, persons who use indoor tanning beds, and persons with a history of sunburns or previous skin cancer. Specific risk factors for melanoma include having a dysplastic nevus (atypical mole), having multiple (ie, ≥100) nevi, and having a family history of melanoma.34 Like most types of cancer, the risk of melanoma increases with age; the median age at diagnosis is 63 years, and the median age at death is 69 years.1


Clinical

Patient Population Under Consideration

This recommendation applies to asymptomatic adults who do not have a history of premalignant or malignant skin lesions. Patients who present with a suspicious skin lesion or who are already under surveillance because of a high risk of skin cancer, such as those with a familial syndrome (eg, familial atypical mole and melanoma syndrome), are outside the scope of this recommendation statement.

Assessment of Risk

Skin cancer of any type occurs more commonly in men than in women and among persons with a fair complexion, persons who use indoor tanning beds, and persons with a history of sunburns or previous skin cancer. Specific risk factors for melanoma include having a dysplastic nevus (atypical mole), having multiple (ie, ≥100) nevi, and having a family history of melanoma.34 Like most types of cancer, the risk of melanoma increases with age; the median age at diagnosis is 63 years, and the median age at death is 69 years.1

Suggestions for Practice Regarding the I Statement

Potential Benefit of Early Detection and Treatment

Direct evidence to assess the effect of screening with a clinical visual skin examination on the risk of death from skin cancer is limited.3 A single ecologic study (Skin Cancer Research to Provide Evidence for Effectiveness of Screening in Northern Germany [SCREEN]) with important methodological limitations suggests that a 1-time, general population-based screening program (with limited participation of 19%) combined with a disease awareness campaign may result in, at most, 1 fewer death due to melanoma per 100,000 persons over a decade.5 An independent analysis of the SCREEN population found that the observed melanoma mortality rate returned to preintervention levels after 5 years of follow-up (Figure).6

Potential Harms of Early Detection and Treatment

Information on the harms of screening is also sparse.3 The majority of suspicious skin lesions excised during screening are not cancerous; for example, the SCREEN study found that between 20 and 55 excisions were performed to detect 1 case of melanoma, depending on patient age.7 The SCREEN study did not report the number of excisions required to prevent 1 death from melanoma, but it can be estimated at more than 4,000. Overdiagnosis and overtreatment—the diagnosis and treatment of cancer that would never have harmed the patient in the absence of screening—are other important potential harms. Ecologic evidence suggests that screening with a visual skin examination results in the overdiagnosis of skin cancer;89 however, current evidence is insufficient to be reliably certain of the magnitude of this effect.

Current Practice

Contemporary data on clinician practice patterns related to skin cancer screening are limited. A 2005 survey of US physicians found that 81% of dermatologists, 60% of primary care physicians, and 56% of internists reported performing a full-body visual skin cancer screening examination on their adult patients.10

Screening Tests

The clinical visual skin examination assesses skin lesions using the “ABCDE rule,” which involves looking for the following characteristics: asymmetry, border irregularity, nonuniform color, diameter greater than 6 mm, and evolving over time.

Screening Interval

The optimal interval for visual skin examination by a clinician to screen for skin cancer, if it exists, is unknown.

Treatment

Treatment of screen-detected melanoma generally involves excision, with or without lymph node management, depending on the stage at diagnosis. There are a variety of treatments available for squamous and basal cell carcinoma (which have excellent cure rates), including surgical excision, Mohs micrographic surgery, radiation therapy, curettage and electrodessication, and cryosurgery, among other options.

Other Approaches to Prevention

The USPSTF recommends that children, adolescents, and young adults aged 10 to 24 years who have fair skin be counseled about minimizing their exposure to ultraviolet radiation to reduce their risk of developing skin cancer.11

Useful Resources

The Community Preventive Services Task Force has made a number of recommendations related to preventing skin cancer through the use of interventions that target child care centers; outdoor occupational, recreational, and tourism settings; primary and middle schools; and communities (available at www.thecommunityguide.org/cancer/index.htmlThis link goes offsite. Click to read the external link disclaimer).


Rationale

Importance

Skin cancer includes melanoma and basal and squamous cell carcinoma. Basal and squamous cell carcinoma, known together as nonmelanoma skin cancer, are the most common types of cancer in the United States and represent the vast majority of all cases of skin cancer (>98%).1 However, nonmelanoma skin cancer rarely results in death or substantial morbidity (<0.1% of patient deaths are caused by this type of cancer), whereas melanoma skin cancer has notably higher mortality rates.1 For this reason, although a visual skin examination by a clinician will detect all 3 of these cancer types, in understanding the potential benefit of screening, the USPSTF prioritized outcomes related to melanoma in developing this recommendation statement. In 2016, an estimated 76,400 US men and women will develop melanoma and 10,100 will die from the disease.1

Detection

Evidence is adequate that visual skin examination by a clinician has modest sensitivity and specificity for detecting melanoma. Evidence is more limited and inconsistent regarding the accuracy of the clinical visual skin examination for detecting nonmelanoma skin cancer.2

Benefits of Early Detection and Treatment

Evidence is inadequate to reliably conclude that early detection of skin cancer through visual skin examination by a clinician reduces morbidity or mortality.

Harms of Early Detection and Treatment

Evidence is adequate that visual skin examination by a clinician to screen for skin cancer leads to harms that are at least small, but current data are insufficient to precisely bound the upper magnitude of these harms. Potential harms of skin cancer screening include misdiagnosis, overdiagnosis, and the resulting cosmetic and—more rarely—functional adverse effects resulting from biopsy and overtreatment.

USPSTF Assessment

The USPSTF concludes that the current evidence is insufficient and that the balance of benefit and harms of visual skin examination by a clinician to screen for skin cancer in asymptomatic adults cannot be determined.


Others

Research Needs and Gaps The USPSTF recognizes the challenge of conducting a definitive randomized clinical trial (RCT) on primary screening, with cause-specific mortality as an end point, to provide clear evidence on the efficacy of the clinical visual skin examination in screening for skin cancer, given the comparatively low rate of death from melanoma in the population (even among persons at higher risk). If adequately powered RCTs are not possible, a high-quality case-control study could provide sufficient power without requiring a large sample size. However, this study design has limitations in the ability to create an appropriate comparison group, the ability to accurately measure the exposure of interest (because of recall bias and other sources of misclassification), healthy volunteer bias (persons receiving skin examinations likely have other good health habits), and other unmeasured sources of confounding. Studies would have to be carefully designed to avoid these threats to validity. Despite these challenges, the USPSTF concludes that further evidence is necessary to advance the field on this essential question. An optimized version of the SCREEN study (ie, a time-series study), in which the clinical visual skin examination alone, without the potential confounding of a second intervention, is evaluated, would also be useful. Additional research on the possible harms of screening for skin cancer—particularly the potential for overdiagnosis and overtreatment—is also needed to help fully understand the ultimate net benefit of the clinical visual skin examination. Update of Previous USPSTF Recommendations This recommendation updates the 2009 USPSTF recommendation.18 The USPSTF has again concluded that the current evidence is insufficient to assess the balance of benefit and harms of screening for skin cancer in adults with a clinical visual skin examination. However, the USPSTF decided to no longer include a statement about patient skin self-examination in the current recommendation. This intervention will be addressed in the USPSTF’s update of its recommendation statement on counseling to prevent skin cancer. Recommendations of Others Most professional organizations in the United States have no specific recommendations about screening for skin cancer with the clinical visual skin examination. The American College of Physicians has no current guidance on skin cancer screening performed by a clinician, nor does the American College of Preventive Medicine (the latter has an archived statement from 199819). The American Academy of Family Physicians concludes that the current evidence is insufficient to assess the balance of benefit and harms of visual skin cancer screening in adults.20 The American Academy of Dermatology does not have formal guidelines on skin cancer screening, although it does encourage and provide resources for its physician members to hold free skin cancer screening events for the public.21 The American Cancer Society recommends that adults 20 years and older who receive periodic health examinations should have their skin examined as part of a general cancer-related checkup.22


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