Clinical Inquiries

Does screening by primary care providers effectively detect melanoma and other skin cancers?

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EVIDENCE-BASED ANSWER:

Possibly. No trials have directly assessed detection of melanoma and other skin cancers by primary care providers.

Training a group comprised largely of primary care physicians to perform skin cancer screening was associated with a 41% increase in skin cancer diagnoses but no change in melanoma mortality.

Visual screening for melanoma by primary care physicians is 40% sensitive and 86% specific (compared with 49% and 98%, respectively, for dermatologists and plastic surgeons).

Melanomas found by visual screening are 38% more likely to be thin (≤ 0.75 mm) than melanomas discovered without screening, which correlates with improved outcomes.

Visual skin cancer screening overall is associated with false-positive rates as follows: 28 biopsies for each melanoma detected, 9 to 10 biopsies for each basal cell carcinoma, and 28 to 56 biopsies for squamous cell carcinoma. False-positive rates are higher for women—as much as double the rate for men—and younger patients—as much as 20-fold the rate for older patients (strength of recommendations for all foregoing statements: B, cohort studies).


 

References

EVIDENCE SUMMARY

No trials have directly assessed skin cancer morbidity associated with physician visual skin screening. A 2018 ecologic cohort study found no difference in melanoma mortality in a population undergoing a national screening program, although screening was associated with 41% more diagnoses of skin cancer.1 A 2012 cohort study found a reduction in melanoma mortality over 7 years associated with a population-based visual skin cancer screening program compared with similar populations that didn’t undergo specific screening.2 At 12-year follow-up, however, there was no longer a difference in mortality.

Primary care visual screening doesn’t decrease melanoma mortality

German researchers trained 1673 non-­dermatologists (64% of general practitioners, obstetrician-gynecologists, and urologists in that region of Germany) and 116 dermatologists (98% in the region) to recognize skin cancer through whole-body visual inspection.1 They recruited and screened 360,000 adults (19% of the population older than 20 years; 74% women) and followed age- and sex-adjusted melanoma mortality over the next 10 years. Non-dermatologists performed most screening exams (77%); 37% of screened positive patients were lost to follow-up.

Melanoma mortality ultimately didn’t change in the screened region, compared with populations in other European countries without national screening programs. Screening detected approximately half of melanoma cases (585/1169) in the region and was associated with 41% greater detection of skin cancers compared with other countries.

Researchers recorded age-adjusted increases in incidence per 100,000 of melanoma from 14.2 (95% confidence interval [CI], 13.3-15.1) to 18 (95% CI, 16.6-19.4), melanoma in situ from 5.8 (95% CI, 5.2-6.4) to 8.5 (95% CI, 7.5-9.5), squamous cell carcinoma from 11.2 (95% CI, 10.6-11.8) to 12.9 (95% CI, 12.0-13.8), and basal cell carcinoma from 60.5 (95% CI, 59.0-62.1) to 78.4 (95% CI, 75.9-80.8).

Visual screening by primary care providers vs screening by ­dermatologists

A cohort study of 16,383 Australian adults found that visual screening by primary care physicians detected melanoma over 3 years with a sensitivity of 40.2% (95% CIs not supplied) and specificity of 86.1% (95% CI, 85.6-86.6%; positive predictive value = 1.4%).3

A second cohort study, enrolling 7436 adults, that evaluated visual screening by dermatologists and plastic surgeons over 2 years found a sensitivity for melanoma of 49% (95% CI, 34.4-63.7%) and a specificity of 97.6% (95% CI, 97.2-97.9%) with a positive predictive value of 11.9% (95% CI, 7.8-17.2%).4

Visual screening more often detects thinner melanomas

A 3-year case-control study (3762 cases, 3824 controls) that examined the association between visual skin screening by a physician (type of physician not specified) and thickness of melanomas detected found that thin melanomas (≤ 0.75 mm) were more common among screened patients compared with unscreened patients (odds ratio [OR] = 1.38; 95% CI, 1.22-1.56) and thicker melanomas (≥ 0.75 mm) were less common (OR = 0.86; 95% CI, 0.75-0.98).5

Continue to: A systematic review...

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