Diagnostic accuracy in skin cancer clinics: the Australian experience

BACKGROUND: Australia, with the world's highest incidence of skin cancer, has witnessed the emergence of "open access" skin cancer clinics during the past decade. These clinics are becoming increasingly popular destinations for the diagnosis and treatment of skin cancers, yet little is known about the diagnostic performance of practitioners in this setting. We sought to measure the accuracy of clinical diagnosis in this setting. METHODS: Clinical and histological data were obtained from 199 consecutive patients undergoing biopsy or excision for 287 skin lesions. We measured the sensitivity, specificity and predictive value of the clinical diagnoses compared with histological diagnoses. RESULTS: Of 287 biopsied or excised lesions, the most common were benign nevi (24%) and basal cell carcinomas (22%), followed by actinic keratoses (11%), dysplastic nevi (11%) and squamous cell carcinomas (7%). Sensitivity was highest for diagnosing BCC (0.89, 95%CI 0.78-0.95) and dysplastic nevi (0.80, 95%CI 0.61-0.93), and lowest for actinic keratoses and the group of benign lesions. Specificity was greater than 0.93 for all diagnoses except BCC (0.76, 95%CI 0.70-0.81). Treating clinicians perceived moderate to strong pressure to excise 49% of lesions overall, but in particular for benign nevi (73%). CONCLUSIONS: Australian family practitioners in open access skin cancer clinics diagnose a wide range of skin lesions with high specificity and moderate to high sensitivity. Benign nevi are accurately diagnosed and often excised because of patient pressure.