Diagnostic Accuracy of Skin Cancer by Family Physicians

Skin cancer is the most common type of cancer worldwide. Family physicians (FPs) need to differentiate between nonmalignant and malignant skin conditions, but the diagnostic accuracy of FPs has never been studied in primary care.

To assess the accuracy of skin cancer diagnoses by FPs. Our secondary aim was to analyze the number of patients with premalignant lesions and examine the diversity of skin-related questions in Dutch primary care.

This study is a retrospective cohort of all new skin-related health questions between January 1, 2018, and July 1, 2018, in a Dutch primary care registration network with data from 26 FPs in 6 practices, with a follow-up of at least 1 year. The initial FP diagnosis was dichotomized as malignant or nonmalignant and compared in a crosstab to the final diagnosis registered after the follow-up period (reference standard).

Our study population included 2952 patients. During the research period, 35 patients received a final diagnosis of skin cancer. The sensitivity and specificity of the FP diagnosis of malignancy was 74.3% (95% confidence interval [CI], 56.7% to 87.5%) and 97.3% (95% CI, 96.7% to 97.8%), the positive predictive value and negative predictive value was 21.5% (95% CI, 17.2% to 26.5%) and 99.7% (95% CI, 99.5% to 99.8%), respectively. Seventy-two patients were diagnosed with a premalignant lesion. Included patients received 141 different diagnoses.

The calculated diagnostic accuracy of FPs is high and shows that FPs are especially accurate in excluding malignancy. This research shows the variety of skin problems in primary care and shows that the FP can deliver safe and effective dermatologic care.