Physician assistants miss the grade on melanoma diagnosis?

May 3, 2018

In a comparison of the performance between physician assistants and dermatologists, physician assistants performed more skin biopsies per case of skin cancer and diagnosed fewer melanomas in situ, a study shows.

Physician assistants have lower diagnostic accuracy for melanoma than dermatologists. In a comparison of the performance between physician assistants and dermatologists, physician assistants performed more skin biopsies per case of skin cancer and diagnosed fewer melanomas in situ, found researchers led by Laura Ferris, M.D., Ph.D., from the University of Pittsburgh, Department of Dermatology.

For the study, published in JAMA Dermatology, the investigators analyzed the medical records of 33,647 skin screening examinations in 20,270 unique patients. About two-thirds (64.9%) had a single screening visit. Patients with a history of melanoma were more likely to see a dermatologist, whereas those with a history of any type of skin cancer were more likely to see a physician assistant. Fifteen dermatologists and 15 physician assistants provided the skin cancer screening.

Physician assistants performed biopsies at a rate of 22.9% compared with 20.8% for dermatologists (P < .001). The rate of biopsy of pigmented lesions was also higher for the physician assistants versus dermatologists (12.9% vs. 11.1%, P < .001).

Screenings performed by dermatologists were more likely to result in a diagnosis of melanoma in situ 1.8% vs. 1.1%, P = .02), but not invasive melanomas (0.8% vs. 0.7%, P = 0.83) or nonmelanoma skin cancer (6.1% vs. 6.1%, P = 0.98). Breslow depth for invasive melanomas did not differ significantly between the two groups.

To diagnose one case of skin cancer, the mean number needed to biopsy was 3.9 for PAs and 3.3 for dermatologists (P < .001). To diagnose one case of melanoma, the mean number needed to biopsy was 39.4 for PAs and 25.4 for dermatologists (P = 0.007). Although it costs less to hire a PA than a dermatologist, more than just clinician salary must be considered in determining the cost of care, conclude the authors.

“Missed diagnoses or unnecessary biopsies of benign lesions should be factored into decisions about the scope of a practice, hiring decisions, supervision of providers and patient decisions about who provides their dermatologic care,” Dr. Ferris and colleagues wrote.

More on this subject from Dermatology Times:  "Melanoma diagnosis by physician or PA not always straightforward"

 

REFERENCES

Ayce M. Anderson, PhD; Martha Matsumoto, MD; Melissa I. Saul, MS; et al.  “Accuracy of skin cancer diagnosis by physician assistants compared with dermatologists in a large health care system,” JAMA Dermatology. April 18, 2018. DOI:10.1001/jamadermatol.2018.0212