The impact of subspecialization and dermatoscopy use on accuracy of melanoma diagnosis among primary care doctors in Australia

Background: Dermatoscopy improves accuracy of melanoma diagnosis, but the impact of subspecialization in skin cancer practice among general practitioners on melanoma diagnostic accuracy is not known.

Objective: To assess the impact of dermatoscopy use and subspecialization on the accuracy of melanoma diagnosis by general practitioners.

Methods: We did a prospective study on the Skin Cancer Audit Research Database and measured melanoma 'number needed to treat' (NNT), with 21,900 lesions excised to diagnose 2367 melanomas.

Results: Melanoma NNT fell from a high of 17.0 (95% confidence interval [CI] 14.5-20.7) among general practitioners with a generalist practice to 9.4 (CI 8.9-10.1) among those with a specific interest in skin cancer, and 8.5 (CI 8.1-9.0) among those practicing only skin cancer medicine (P < .0001). Melanoma NNT fell from a high of 14.6 (CI 12.0-18.6) among dermatoscopy low/non-users to 10.9 (CI 9.8-12.4) among medium users, and 8.9 (CI 8.6-9.3) among high users (P < .0001). The association between NNT and practice type remained (P < .0001) when adjusted for dermatoscopy use and other variables. The association between NNT and dermatoscopy use disappeared (P = .41) when adjusted for practice type and other variables.

Limitations: There is selection bias with respect to participating doctors and completeness and accuracy of data are not independently verified in the Skin Cancer Audit Research Database (SCARD).

Conclusions: General practitioners who subspecialize in skin cancer have a higher use of dermatoscopy and diagnose melanoma with greater accuracy than their generalist counterparts.