Predicting cutaneous melanoma: a systematic review of clinical prediction rules

Problem

Cutaneous malignant melanoma incidence is increasing worldwide. It is the fifth most common cancer in the UK and the leading cause of skin cancer mortality. Early diagnosis improves prognosis. Clinical prediction rules (CPRs) can be used to stratify patients with symptoms and signs of suspected malignant melanoma to improve early diagnosis. The initial presentation of melanoma occurs most frequently in primary care and ambulatory care settings. The aim of this systematic review was to evaluate the performance and impact of existing clinical prediction rules for melanoma diagnosis in patients with a pigmented skin lesion, in primary care and other ambulatory care settings.

Approach

A systematic search of electronic literature databases was conducted using a search string containing a combination of MeSH terms and keywords. Studies deriving and validating, validating or assessing the impact of a CPR for predicting melanoma diagnosis in ambulatory care were included. Data extraction and methodological quality assessment were guided by the CHARMS checklist. Meta-analysis was conducted using Stata version 12.

Findings

From 16,334 studies reviewed, 50 were included, validating performance of 24 unique CPRs. 18 CPRs utilized dermoscopy or a novel diagnostic technology. 2 impact analysis studies set in primary care were identified. 48 validation studies were identified, of which 3 were set in primary care. The most commonly evaluated CPRs were the ABCD dermoscopy rule (8 studies; pooled sensitivity 0.85, 95% CI 0.73-0.93, specificity 0.72, 95% CI 0.65-0.78) and the 7 point checklist for dermoscopy (11 studies; pooled sensitivity 0.77, 95% CI 0.61-0.88, specificity 0.80, 95% CI 0.59-0.92). There was insufficient data in the remaining 29 validation studies for meta-analysis and a narrative synthesis of these was undertaken. The methodological quality of studies varied.

Consequences

The ABCD dermoscopy rule is more useful for ruling out melanoma than the 7 point checklist for dermoscopy. There is limited evidence to date on the performance and impact of melanoma CPRs in primary care, particularly CPRs that do not require use of dermoscopy. A focus on impact analysis will help translate melanoma risk prediction rules into useful tools for primary care.