Current approach of skin lesions suspected of malignancy in general practice in the Netherlands: a quantitative overview

Practitioner characteristics, diagnostic accuracy metrics and discovering-individual with respect to 637 melanomas documented by 27 general practitioners on the Skin Cancer Audit Research Database

BACKGROUND AND OBJECTIVE

Knowledge of accuracy for melanoma diagnosis and melanoma discovering-individual in primary care is limited. We describe general practitioner (GP) characteristics and analyse defined diagnostic accuracy metrics for GPs in the current study comparing this with a previous study for GPs common to both, and we analyse the individual first discovering each melanoma as a lesion of concern.

METHODS

The characteristics and diagnostic accuracy of 27 Australasian GPs documenting 637 melanomas on the Skin Cancer Audit Research Database (SCARD) in 2013 were described and analysed. The number needed to treat (NNT) and percentage of melanomas that were in situ (percentage in situ) were analysed as surrogates for specificity and sensitivity, respectively. The discovering-individual was analysed according to patient age and sex and lesion Breslow thickness.

RESULTS

The average NNT and percentage in situ were 5.73% and 65.07%, respectively. For 21 GPs in both a 2008-2010 study and the current study, the NNT was 10.78 and 5.56, respectively (p = 0.0037). A consistent trend of decreasing NNT and increasing percentage in situ through increasingly subspecialised GP categories did not reach statistical significance. NNT trended high at ages and sites for which melanoma was rare. While the patient or family member was more likely to discover thick melanomas and melanomas in patients under 40 years, GPs discovered 73.9% of the melanomas as lesions of concern.

CONCLUSIONS

GPs were the discovering-individuals for the majority of melanomas in the current study and their accuracy metrics compared favourably with published figures for dermatologists and GPs.

Artificial intelligence in mobile health for skin cancer diagnostics at home (AIM HIGH): a pilot feasibility study

Background

Artificial intelligence (AI)-based mobile phone apps (mHealth) have the potential to streamline care for suspicious skin lesions in primary care. This study aims to investigate the conditions and feasibility of a study that incorporates an AI-based app in primary care and evaluates its potential impact.

Methods

We conducted a pilot feasibility study from November 22nd, 2021 to June 9th, 2022 with a mixed-methods design on implementation of an AI-based mHealth app for skin cancer detection in three primary care practices in the Netherlands (Rotterdam, Leiden and Katwijk). The primary outcome was the inclusion and successful participation rate of patients and general practitioners (GPs). Secondary outcomes were the reasons, facilitators and barriers for successful participation and the potential impact in both pathways for future sample size calculations. Patients were offered use of an AI-based mHealth app before consulting their GP. GPs assessed the patients blinded and then unblinded to the app. Qualitative data included observations and audio-diaries from patients and GPs and focus-groups and interviews with GPs and GP assistants.

Findings

Fifty patients were included with a median age of 52 years (IQR 33.5-60.3), 64% were female, and 90% had a light skin type. The average patient inclusion rate was 4-6 per GP practice per month and 84% (n = 42) successfully participated. Similarly, in 90% (n = 45 patients) the GPs also successfully completed the study. GPs never changed their working diagnosis, but did change their treatment plan (n = 5) based on the app's assessments. Notably, 54% of patients with a benign skin lesion and low risk rating, indicated that they would be reassured and cancel their GP visit with these results (p < 0.001).

Interpretation

Our findings suggest that studying implementation of an AI-based mHealth app for detection of skin cancer in the hands of patients or as a diagnostic tool used by GPs in primary care appears feasible. Preliminary results indicate potential to further investigate both intended use settings.

Funding

SkinVision B.V.

Measuring the quality of skin cancer management in primary care: A scoping review

Skin cancer is a growing global problem and a significant health and economic burden. Despite the practical necessity for skin cancer to be managed in primary care settings, little is known about how quality of care is or should be measured in this setting. This scoping review aimed to capture the breadth and range of contemporary evidence related to the measurement of quality in skin cancer management in primary care settings. Six databases were searched for relevant texts reporting on quality measurement in primary care skin cancer management. Data from 46 texts published since 2011 were extracted, and quality measures were catalogued according to the three domains of the Donabedian model of healthcare quality (structure, process and outcome). Quality measures within each domain were inductively analysed into 13 key emergent groups. These represented what were deemed to be the most relevant components of skin cancer management as related to structure, process or outcomes measurement. Four groups related to the structural elements of care provision (e.g. diagnostic tools and equipment), five related to the process of care delivery (e.g. diagnostic processes) and four related to the outcomes of care (e.g. poor treatment outcomes). A broad range of quality measures have been documented, based predominantly on articles using retrospective cohort designs; systematic reviews and randomised controlled trials were limited.

To Refer or Not to Refer in Teledermoscopy: Retrospective Study

BACKGROUND

Challenges remain for general practitioners (GPs) in diagnosing (pre)malignant and benign skin lesions. Teledermoscopy (TDsc) supports GPs in diagnosing these skin lesions guided by teledermatologists' (TDs) diagnosis and advice and prevents unnecessary referrals to dermatology care. However, the impact of the availability of TDsc on GPs' self-reported referral decisions to dermatology care before and after the TDsc consultation is unknown.

OBJECTIVE

The objective of this study is to assess and compare the initial self-reported referral decisions of GPs before TDsc versus their final self-reported referral decisions after TDsc for skin lesions diagnosed by the TD as (pre)malignant or benign.

METHODS

TDsc consultations requested by GPs in daily practice between July 2015 and June 2020 with a TD assessment and diagnosis were extracted from a nationwide Dutch telemedicine database. Based on GP self-administered questions, the GPs' referral decisions before and their final referral decision after TDsc consultation were assessed for (pre)malignant and benign TD diagnoses.

RESULTS

GP self-administered questions and TD diagnoses were evaluated for 6364 TDsc consultations (9.3% malignant, 8.8% premalignant, and 81.9% benign skin lesions). In half of the TDsc consultations, GPs adjusted their initial referral decision after TD advice and TD diagnosis. Initially, GPs did not have the intention to refer 67 (56.8%) of 118 patients with a malignant TD diagnosis and 26 (16.0%) of 162 patients with a premalignant TD diagnosis but then decided to refer these patients after the TDsc consultation. Furthermore, GPs adjusted their decision from referral to nonreferral for 2534 (74.9%) benign skin lesions (including 676 seborrheic keratosis and 131 vascular lesions).

CONCLUSIONS

GPs adjusted their referral decision in 52% (n=3306) of the TDsc consultations after the TD assessment. The availability of TDsc is thus of added value and assists GPs in their (non)referral for patients with skin lesions to dermatology care. TDsc resulted in referrals of patients with (pre)malignant skin lesions that GPs would not have referred directly to the dermatologist. TDsc also led to a reduction of unnecessary referrals of patients with low complex benign skin lesions (eg, seborrheic keratosis and vascular lesions).

Eleven years of teledermoscopy in the Netherlands: A retrospective quality and performance analysis of 18,738 consultations

INTRODUCTION

Teledermoscopy supports and enhances the early detection of skin lesions by general practitioners in primary practice through remote consultation with dermatologists. Teledermoscopy has been a regular health service in Dutch primary care since February 2009. Teledermoscopy quality and performance outcomes on Dutch general practitioner primary care 11 years after its implementation were assessed.

METHODS

Dutch primary care teledermoscopy consultation data was retrospectively analysed on timestamps and responses on non-mandatory evaluation questions posed to the general practitioner and teledermatologist during the teledermoscopy consultation process. Anonymized data (February 2009-February 2020) was extracted from a Dutch teledermoscopy service database. The timestamps and evaluation questions data were subject to the teledermoscopy quality and performance outcomes. A limited cost evaluation was performed.

RESULTS

A total of 18,738 teledermoscopy consultations were sent by 1341 general practitioners (February 2009-February 2020). For 3908 (31.9%) teledermoscopy consultations, the general practitioner requested second opinion advice which led to 712 (18.2%) extra teledermoscopy referrals of patients who would not have been referred without teledermoscopy, including skin cancer teledermoscopy diagnoses. The general practitioner followed the teledermatologists' advice on patient referral for 8813 (88.5%) patients, reported 97.3% of the teledermoscopy consultations as helpful and 95.1% as instructive, referred 68.0% less patients with teledermoscopy availability, referred overall 59.4% less patients, and needed 5.4 minutes (median) for sending a teledermoscopy consultation. Teledermatologist's median answer and response time was 2 minutes and 2.4 hours, respectively. The estimated cost reduction was €144.18 ($164.65) (50.2%) per teledermoscopy patient.

DISCUSSION

Teledermoscopy is a useful service in general practitioner practice for requesting dermatologist advice in primary care settings to support the detection of skin lesion at an early stage and at lower costs. Teledermoscopy could also decrease the burden of secondary dermatology care since general practitioners reported that they did not refer the majority of patients to a dermatologist after the teledermoscopy consultation compared to their initial referral decision. General practitioners reported the teledermoscopy system as helpful and instructive which could contribute to enhancement of their dermatological knowledge.

Early Melanoma Detection in Primary Care: Clinical Recognition of Melanoma is Not Enough, One Must Also Learn the Basics

To improve early melanoma detection, educational programs have been developed for general practitioners (GPs). This study aimed to determine whether the adjunct of teaching basic knowledge of pigmented skin lesions (PSL) to the training in melanoma diagnosis improves the GPs' diagnostic accuracy of melanoma. An interventional prospective study was conducted over a 3-month period where GPs attended a 2-h training course. The 1^st session taught clinical melanoma recognition and the 2^nd session instructed basic knowledge of PSL. Prior to training, after the 1^st, and after the 2^nd session, GPs were asked to select the malignant or benign nature of 15 clinical images associated to their clinical history. In total, 56 GPs participated in this study. The number of GPs identifying correctly ≥ 50% of the melanomas increased the most after the 1^st session from 15 (26.8%; CI = (15.2; 38.4)) to 44 (78.6%; CI = (67.8; 89.3)) GPs (P < 0.001). The number of GPs correctly identifying ≥ 50% of the benign PSL only increased after completing the entire training, going from 10 (17.9%; CI = [(7.8; 27.9)) GPs to 50 (89.3%; CI = (81.2; 97.4)) GPs (P < 0.001). In this study, GPs identified benign PSL most accurately after the 2^nd session. This suggested that teaching GPs the basics of PSL would especially improve their diagnostic accuracy for benign PSL, which could reduce unnecessary referrals to dermatologists. Teaching basic knowledge of PSL in addition to melanoma recognition seemed to enable GPs to triage skin lesions more effectively than when they were only trained to recognize melanoma.

Burden of skin cancer in Colombia

BACKGROUND

Levels of incidence and mortality of skin cancer in Colombia and Latin America are largely unknown.

OBJECTIVES

Present the available information from official and gray literature and governmental databases to grasp the magnitude and characteristics of skin cancer in Colombia (middle-income Latin American country).

METHODS

Narrative review based on a literature search (2005-2020), gray literature and cancer registry and governmental warehouse data, calculation of proportions and age-standardized incidence (ASIR) and mortality rates (ASMR), expressed per 100,000 person-years.

RESULTS

ASIR of cutaneous melanoma in Colombia is around 3, corresponding ASMR between 0.7 and 0.8. Distinctive features are the high proportion and rates for acral melanomas, and the advanced stage at diagnosis in the general population but not in private clinics. For non-melanoma skin cancer, ASIR is at least around 35-40, ASMR 0.8.

CONCLUSIONS

Among the wealthy Colombians, melanoma features are similar to those of high incidence countries (but of lower magnitude), whereas the majority of the population present distinct features with a much higher proportion of acral melanomas, very late stages at diagnosis, and poor prognosis. More advanced melanomas seem to have a relation with lower socioeconomic status. Non-melanoma skin cancer is common, with very high mortality rates at levels even above those of predominantly fair-skinned populations, implying high fatality rates for non-melanoma skin cancers. This could indicate a late diagnosis or difficulties in access to treatment, illustrating the need for primary and secondary prevention to reduce the burden of disease and improve the prognosis of this common cancer.

Early detection of melanoma in specialised primary care practice in Australia

BACKGROUND

Primary care skin cancer clinics facilitate early treatment of melanoma in Australia. We investigated the clinical and histopathological features of melanomas diagnosed and treated in an established clinic in Brisbane.

METHODS

Retrospective audit of medical records of patients diagnosed with in situ or invasive primary cutaneous melanoma in a primary care clinic specializing in skin cancer, 2000-2017. Demographic and clinical data were standardly extracted by a medically-trained investigator. We used descriptive analyses to assess characteristics of patients and melanomas, and examine surgical management according to tumour thickness.

RESULTS

Of 380 patients (median age 57 years; 57 % male) newly diagnosed with 497 histologically-confirmed primary cutaneous melanomas, 369 were in situ and 128 invasive. Of the 369 in situ melanomas, 143 (39 %) were on the trunk and 87 (24 %) on the head and neck; 247 (67 %) were diagnosed by shave biopsy; and 141 (38 %) referred for wide local excision (WLE). Of the 128 invasive melanomas, only 21 (16 %) had thickness ≥ 0.8 mm and these occurred more often on head and neck than thin invasive melanomas (p = 0.02). The majority of invasive melanomas were diagnosed by excision biopsy, and WLE was carried out in a median of 3 days (melanomas ≥ 0.8 mm) and 2 days (<0.8 mm). The doctor detected the majority of in situ (83 %) and thin invasive (73 %) melanomas during surveillance, compared with 48 % of thicker invasive melanomas ≥ 0.8 mm (p < 0.001).

CONCLUSION

In Australia, specialised primary care practice plays a major role in detection and treatment of early primary melanoma.

Introducing teledermoscopy of possible skin cancers in general practice in Southern Denmark

BACKGROUND

The increasing incidence of skin cancers poses a burden to health care systems. General practitioners (GPs) play an important role in triaging these diseases and referring relevant patients to specialists. It is challenging to distinguish benign from malignant skin lesions, and GPs may benefit from diagnostic support from teledermoscopy (TD).

OBJECTIVES

To assess whether the introduction of TD in general practice was feasible and might reduce the number of unnecessary referrals to specialists and to assess the diagnostic accuracy and confidence of participating GPs.

METHODS

Fifty general practices in Southern Denmark participated. Adult patients presenting to their GP with suspected skin cancer could be included. Images including dermoscopy were taken by the GP and sent for evaluation by specialized dermatologists at a university hospital. Patients were simultaneously referred for a face-to-face evaluation at the university hospital. Diagnoses proposed by the GPs and by TD were compared to the final diagnoses obtained by histopathology or, if not available, face-to-face evaluation.

RESULTS

Five hundred and nineteen patients with 600 suspected skin cancers were included. The final diagnosis was benign in 72.3%. The photo quality was good or fair in 90.5%. GPs reported uncertainty about their diagnoses in 41.5% of cases. The GPs' positive predictive values for any malignancy and for malignant melanoma were 49.5% and 26.3%, respectively. On evaluation by TD, 31.5% of lesions did not need further in-person assessment.

CONCLUSION

Useful images of suspicious skin lesions were obtained from general practice, and GPs could benefit from TD to improve their diagnostic accuracy and confidence.

Accuracy of a smartphone application for triage of skin lesions based on machine learning algorithms

BACKGROUND

Machine learning algorithms achieve expert-level accuracy in skin lesion classification based on clinical images. However, it is not yet shown whether these algorithms could have high accuracy when embedded in a smartphone app, where image quality is lower and there is high variability in image taking scenarios by users. In the past, these applications were criticized due to lack of accuracy.

OBJECTIVE

In this study, we evaluate the accuracy of the newest version of a smartphone application (SA) for risk assessment of skin lesions.

METHODS

This SA uses a machine learning algorithm to compute a risk rating. The algorithm is trained on 131 873 images taken by 31 449 users in multiple countries between January 2016 and August 2018 and rated for risk by dermatologists. To evaluate the sensitivity of the algorithm, we use 285 histopathologically validated skin cancer cases (including 138 malignant melanomas), from two previously published clinical studies (195 cases) and from the SA user database (90 cases). We calculate the specificity on a separate set from the SA user database containing 6000 clinically validated benign cases.

RESULTS

The algorithm scored a 95.1% (95% CI, 91.9-97.3%) sensitivity in detecting (pre)malignant conditions (93% for malignant melanoma and 97% for keratinocyte carcinomas and precursors). This level of sensitivity was achieved with a 78.3% (95% CI, 77.2-79.3%) specificity.

CONCLUSIONS

This SA provides a high sensitivity to detect skin cancer; however, there is still room for improvement in terms of specificity. Future studies are needed to assess the impact of this SA on the health systems and its users.

Dermoscopy for melanoma detection and triage in primary care: a systematic review

OBJECTIVE

Most skin lesions first present in primary care, where distinguishing rare melanomas from benign lesions can be challenging. Dermoscopy improves diagnostic accuracy among specialists and is promoted for use by primary care physicians (PCPs). However, when used by untrained clinicians, accuracy may be no better than visual inspection. This study aimed to undertake a systematic review of literature reporting use of dermoscopy to triage suspicious skin lesions in primary care settings, and challenges for implementation.

DESIGN

A systematic literature review and narrative synthesis.

DATA SOURCES

We searched MEDLINE, Cochrane Central, EMBASE, Cumulative Index to Nursing and Allied Health Literature, and SCOPUS bibliographic databases from 1 January 1990 to 31 December 2017, without language restrictions.

INCLUSION CRITERIA

Studies including assessment of dermoscopy accuracy, acceptability to patients and PCPs, training requirements, and cost-effectiveness of dermoscopy modes in primary care, including trials, diagnostic accuracy and acceptability studies.

RESULTS

23 studies met the review criteria, representing 49 769 lesions and 3708 PCPs, all from high-income countries. There was a paucity of studies set truly in primary care and the outcomes measured were diverse. The heterogeneity therefore made meta-analysis unfeasible; the data were synthesised through narrative review. Dermoscopy, with appropriate training, was associated with improved diagnostic accuracy for melanoma and benign lesions, and reduced unnecessary excisions and referrals. Teledermoscopy-based referral systems improved triage accuracy. Only three studies examined cost-effectiveness; hence, there was insufficient evidence to draw conclusions. Costs, training and time requirements were considered important implementation barriers. Patient satisfaction was seldom assessed. Computer-aided dermoscopy and other technological advances have not yet been tested in primary care.

CONCLUSIONS

Dermoscopy could help PCPs triage suspicious lesions for biopsy, urgent referral or reassurance. However, it will be important to establish further evidence on minimum training requirements to reach competence, as well as the cost-effectiveness and patient acceptability of implementing dermoscopy in primary care.

TRIAL REGISTRATION NUMBER

CRD42018091395.

Dermoscopy Use in Primary Care: A Scoping Review

Background

Patients in many countries with new or changing skin lesions will first consult a primary care physician, often called a general practitioner (GP). With the dramatic rise in melanoma incidence over recent decades, dermoscopy offers a tool with an evidence base supporting its use in skin lesion assessment. How GPs use dermoscopy is unclear.

Objectives

A scoping literature review was carried out to examine the current state of published evidence about dermoscopy use in primary care.

Methods

The methodological steps taken in this review followed those developed by Arksey and O'Malley, as revised by Levac and colleagues. Four electronic databases were searched for evidence published up to January 2018 describing the use of dermoscopy in a generalist primary care setting. Seven articles were identified for analysis.

Results

All included articles have been published since 2007. Most were questionnaire studies and revealed that generally a small minority of GPs use dermoscopy, although some jurisdictions such as Australia report greater use. Dermoscopy is generally used only for the assessment of pigmented skin lesions, but is not used consistently. Several perceived barriers to dermoscopy use, including the need for training, have been reported.

Conclusions

There is a paucity of data on dermoscopy use among GPs, and diversity in questionnaire items prevents comparison between jurisdictions. Perceived barriers to dermoscopy use require more in-depth exploration, potentially including qualitative data, to evaluate them more fully. Understanding these factors, including how GPs train in dermoscopy, will be crucial in widening dermoscopy use in primary care.

Dermoscopy, with and without visual inspection, for diagnosing melanoma in adults

BACKGROUND

Melanoma has one of the fastest rising incidence rates of any cancer. It accounts for a small percentage of skin cancer cases but is responsible for the majority of skin cancer deaths. Although history-taking and visual inspection of a suspicious lesion by a clinician are usually the first in a series of 'tests' to diagnose skin cancer, dermoscopy has become an important tool to assist diagnosis by specialist clinicians and is increasingly used in primary care settings. Dermoscopy is a magnification technique using visible light that allows more detailed examination of the skin compared to examination by the naked eye alone. Establishing the additive value of dermoscopy over and above visual inspection alone across a range of observers and settings is critical to understanding its contribution for the diagnosis of melanoma and to future understanding of the potential role of the growing number of other high-resolution image analysis techniques.

OBJECTIVES

To determine the diagnostic accuracy of dermoscopy alone, or when added to visual inspection of a skin lesion, for the detection of cutaneous invasive melanoma and atypical intraepidermal melanocytic variants in adults. We separated studies according to whether the diagnosis was recorded face-to-face (in-person), or based on remote (image-based), assessment.

SEARCH METHODS

We undertook a comprehensive search of the following databases from inception up to August 2016: CENTRAL; MEDLINE; Embase; CINAHL; CPCI; Zetoc; Science Citation Index; US National Institutes of Health Ongoing Trials Register; NIHR Clinical Research Network Portfolio Database; and the World Health Organization International Clinical Trials Registry Platform. We studied reference lists and published systematic review articles.

SELECTION CRITERIA

Studies of any design that evaluated dermoscopy in adults with lesions suspicious for melanoma, compared with a reference standard of either histological confirmation or clinical follow-up. Data on the accuracy of visual inspection, to allow comparisons of tests, was included only if reported in the included studies of dermoscopy.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted all data using a standardised data extraction and quality assessment form (based on QUADAS-2). We contacted authors of included studies where information related to the target condition or diagnostic threshold were missing. We estimated accuracy using hierarchical summary receiver operating characteristic (SROC),methods. Analysis of studies allowing direct comparison between tests was undertaken. To facilitate interpretation of results, we computed values of sensitivity at the point on the SROC curve with 80% fixed specificity and values of specificity with 80% fixed sensitivity. We investigated the impact of in-person test interpretation; use of a purposely developed algorithm to assist diagnosis; observer expertise; and dermoscopy training.

MAIN RESULTS

We included a total of 104 study publications reporting on 103 study cohorts with 42,788 lesions (including 5700 cases), providing 354 datasets for dermoscopy. The risk of bias was mainly low for the index test and reference standard domains and mainly high or unclear for participant selection and participant flow. Concerns regarding the applicability of study findings were largely scored as 'high' concern in three of four domains assessed. Selective participant recruitment, lack of reproducibility of diagnostic thresholds and lack of detail on observer expertise were particularly problematic.The accuracy of dermoscopy for the detection of invasive melanoma or atypical intraepidermal melanocytic variants was reported in 86 datasets; 26 for evaluations conducted in person (dermoscopy added to visual inspection), and 60 for image-based evaluations (diagnosis based on interpretation of dermoscopic images). Analyses of studies by prior testing revealed no obvious effect on accuracy; analyses were hampered by the lack of studies in primary care, lack of relevant information and the restricted inclusion of lesions selected for biopsy or excision. Accuracy was higher for in-person diagnosis compared to image-based evaluations (relative diagnostic odds ratio (RDOR) 4.6, 95% confidence interval (CI) 2.4 to 9.0; P < 0.001).We compared accuracy for (a), in-person evaluations of dermoscopy (26 evaluations; 23,169 lesions and 1664 melanomas),versus visual inspection alone (13 evaluations; 6740 lesions and 459 melanomas), and for (b), image-based evaluations of dermoscopy (60 evaluations; 13,475 lesions and 2851 melanomas),versus image-based visual inspection (11 evaluations; 1740 lesions and 305 melanomas). For both comparisons, meta-analysis found dermoscopy to be more accurate than visual inspection alone, with RDORs of (a), 4.7 (95% CI 3.0 to 7.5; P < 0.001), and (b), 5.6 (95% CI 3.7 to 8.5; P < 0.001). For a), the predicted difference in sensitivity at a fixed specificity of 80% was 16% (95% CI 8% to 23%; 92% for dermoscopy + visual inspection versus 76% for visual inspection), and predicted difference in specificity at a fixed sensitivity of 80% was 20% (95% CI 7% to 33%; 95% for dermoscopy + visual inspection versus 75% for visual inspection). For b) the predicted differences in sensitivity was 34% (95% CI 24% to 46%; 81% for dermoscopy versus 47% for visual inspection), at a fixed specificity of 80%, and predicted difference in specificity was 40% (95% CI 27% to 57%; 82% for dermoscopy versus 42% for visual inspection), at a fixed sensitivity of 80%.Using the median prevalence of disease in each set of studies ((a), 12% for in-person and (b), 24% for image-based), for a hypothetical population of 1000 lesions, an increase in sensitivity of (a), 16% (in-person), and (b), 34% (image-based), from using dermoscopy at a fixed specificity of 80% equates to a reduction in the number of melanomas missed of (a), 19 and (b), 81 with (a), 176 and (b), 152 false positive results. An increase in specificity of (a), 20% (in-person), and (b), 40% (image-based), at a fixed sensitivity of 80% equates to a reduction in the number of unnecessary excisions from using dermoscopy of (a), 176 and (b), 304 with (a), 24 and (b), 48 melanomas missed.The use of a named or published algorithm to assist dermoscopy interpretation (as opposed to no reported algorithm or reported use of pattern analysis), had no significant impact on accuracy either for in-person (RDOR 1.4, 95% CI 0.34 to 5.6; P = 0.17), or image-based (RDOR 1.4, 95% CI 0.60 to 3.3; P = 0.22), evaluations. This result was supported by subgroup analysis according to algorithm used. We observed higher accuracy for observers reported as having high experience and for those classed as 'expert consultants' in comparison to those considered to have less experience in dermoscopy, particularly for image-based evaluations. Evidence for the effect of dermoscopy training on test accuracy was very limited but suggested associated improvements in sensitivity.

AUTHORS' CONCLUSIONS

Despite the observed limitations in the evidence base, dermoscopy is a valuable tool to support the visual inspection of a suspicious skin lesion for the detection of melanoma and atypical intraepidermal melanocytic variants, particularly in referred populations and in the hands of experienced users. Data to support its use in primary care are limited, however, it may assist in triaging suspicious lesions for urgent referral when employed by suitably trained clinicians. Formal algorithms may be of most use for dermoscopy training purposes and for less expert observers, however reliable data comparing approaches using dermoscopy in person are lacking.