Number of skin biopsies needed per malignancy: Comparing the use of skin biopsies among dermatologists and nondermatologist clinicians

Abstract

Background: There are too few board-certified dermatologists to treat all patients with skin disease. Primary care physicians often serve at the frontline of skin cancer screening.

Objective: To compare biopsy use among dermatologist physicians, dermatology advanced practice professionals (APPs), primary care physicians (PCPs), and other nondermatology clinicians.

Methods: Pathology reports, requisition forms, and clinical notes of skin biopsies submitted to our institution during the study period were reviewed. Skin biopsies for inflammatory conditions, cosmetic or functional purposes, and re-excisions were excluded. The number needed to biopsy (NNB) was calculated as the number of biopsied lesions divided by histologically proven skin cancers.

Results: The NNB by clinician type was 2.82 for dermatology physicians, 4.69 for APPs, 4.55 for nondermatology PCPs, and 6.55 for other nondermatology clinicians (P < .001). The NNB was significant between clinician groups for nonmelanoma skin cancer (dermatology physicians, 2.00; APPs, 2.71; PCPs, 2.36; and other nondermatology clinicians, 3.47; P < .001) but not for melanoma (dermatology clinicians, 14.33; APPs, 20.78; PCPs, 27.80; and other nondermatology clinicians, 53.56; P = .061).

Limitations: The NNB represents a measure of use but gives no insight into the number of malignant lesions that go unbiopsied and, therefore, undiagnosed. The prevalence of skin cancer varies among dermatology and nondermatology practices. The results are not generalizable to all practice settings.

Conclusions: Dermatology physicians had the lowest NNB of all clinician groups. PCPs performed similarly to dermatology APPs.

Keywords: biopsy use; number needed to biopsy; primary care physicians; skin cancer.