Dermoscopy in Practice
A. Bernard Ackerman, MD, a key figure in the modern era of dermatopathology, wrote an editorial for the Journal of the American Academy of Dermatology in 1985 titled “No one should die of malignant melanoma.” The editorial highlighted that the visual changes associated with melanoma often manifest years prior to malignant invasion and advocated that all physicians should have competence in melanoma detection, specifically mentioning the importance of training primary care physicians (PCPs), dermatologists, and pathologists in this regard.16 This sentiment is equally as true now as it was in 1985.
Naked eye examination paired with an evaluation of patient risk factors for melanoma, including fair skin types, significant sun exposure history, history of sunburn, geographic location, and personal and family history of melanoma, are the foundation of melanoma detection efforts.17 Studies suggest that the triage skills of PCPs could be improved in regard to the evaluation of pigmented lesions. Primary care residents, for instance, did not accurately diagnose 40% of malignant melanoma cases.18,19 Additionally, a meta-analysis demonstrated that PCP accuracy when diagnosing malignant melanoma ranged between 49% and 80%, significantly less than the 85% to 89% exhibited by practicing dermatologists.19 Dermoscopy could be incorporated as an element of the skin examination to enhance lesion discrimination among PCPs, as it has proven use in dermatologic practice.
Dermoscopy is not readily used by PCPs. A survey study of 705 family practitioners in the US performed by Morris and colleagues demonstrated that only 8.3% of participants currently use a dermatoscope to evaluate pigmented lesions.20 The most common barriers to dermoscopy use cited by PCPs in the US include the cost of the dermatoscope, the time required to acquire proficiency, and the lack of financial reimbursement.16 True utilization of dermoscopy among PCPs is higher than this figure suggests due to the number of PCPs who access dermoscopic evaluations via teledermatology. All 21 Veterans Integrated Services Networks of the Veterans Health Administration (VHA) system, for instance, participate in teledermatology and jointly employ more than 1,150 trained telehealth clinical technicians who created a collective 107,000 teledermatology encounters with and without dermoscopy for evaluation by dermatologists in the most recent fiscal year(Martin Weinstock, written communication, October 2017). Nonetheless, it is necessary to determine the contribution that wider utilization of dermoscopy among PCPs would have on melanoma surveillance.
Studies show that dermoscopic algorithms improve the sensitivity while slightly decreasing the specificity of PCPs to detect melanoma compared with that of the naked eye examination. Dolianitis and colleagues demonstrated that a baseline sensitivity of 60.9% for melanoma detection improved to 85.4% with the 7-point checklist, 85.4% with Menzies method, and 77.5% with the ABCD rule, while the baseline specificity of 85.4% moderated to 73.0%, 77.7%, and 80.4%, respectively, among 61 medical practitioners after studying dermoscopy techniques from 2 CDs.21 Westerhoff and colleagues performed a randomized controlled trial with 74 PCPs to determine the effect of a minimal intervention on melanoma diagnostic accuracy. The intervention consisted of providing participants in the experimental group with an atlas of microscopic features common to melanoma to be read at the participants’ leisure, a 1-hour presentation on microscopy, and a 25-questionpractice quiz. Participants randomized to the intervention group improved their diagnostic accuracy from 57.8% to 75.9% with the use of dermoscopy. This group also experiencedimproved accuracy in its clinical diagnosis of melanoma from 54.6% to 62.7%.22
Argenziano and colleagues demonstrated similar results after PCPs attended a 4-hour workshop on dermoscopy. The 73 PCPs in this study evaluated 2,522 lesions randomized to naked eye examination or dermoscopy. The BMR, calculated from the data provided, improved from 12.6:1 to 10.5:1, respectively, when dermoscopy was incorporated into lesion analysis, while the sensitivity increased from 54.1% to 79.2% and the negative predictive value increased from 95.8% to 98.1%. It is important to note that the BMR and negative predictive value improved in tandem, indicating that PCPs were more discriminatory with their referrals for evaluation by dermatology while capturing a greater percentage of melanomas.23
These studies are not without limitations that preclude broad generalizations. For example, Dolianitis and colleagues and Westerhoff and colleagues provided participants with dermoscopic images of the lesions to be evaluated instead of requiring personal use of a dermatoscope, whereas the study by Argenziano and colleagues incorporated only 6 histopathologically proven malignant melanomas into each of the naked eye examination and the experimental dermoscopy groups.21-23 Yet these studies suggest that broader use of dermoscopy among PCPs could improve the accuracy of melanoma detection given clinically relevant training.
Several additional studies identify positive correlations associated with dermoscopy use among PCPs. A recent survey of 425 French general practitioners found that 8% of the study participants acknowledged owning a dermatoscope. Dermatoscope owners spent a statistically significant longer time analyzing each pigmented skin lesions, exhibited greater confidence in their analysis of pigmented lesions, and issued fewer overall referrals to dermatologists.24
Similarly, Rosendahl and colleagues evaluated the number needed to treat (NNT) (equivalent to the BMR) among 193 Australian PCPs and found that the NNT was inversely correlated to the frequency with which the physicians used dermoscopy. However, it was difficult to determine the definitive cause of the reduced NNT in this study because a similar effect was observed when NNT was evaluated based on general practitioner subspecialization.25 Again, despite limitations, these studies suggest that increased dermoscopy use among PCPs could reduce the morbidity of lifelong scarring as well as the short-term anxiety associated with a possible melanoma diagnosis.