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Non-dermatologists have lower accuracy diagnosing melanoma

By Emily Innes-Leroux

In a retrospective study, dermatologists had a significantly better rate of accurately diagnosing melanoma than physicians of different specialties, including general practitioners and family physicians.

The researchers of the study, published online ahead of print in The Journal of Cutaneous Medicine and Surgery (Dec. 16, 2015), reviewed pathology reports of biopsies submitted to Vancouver Coastal health with clinical diagnoses of melanoma.

The clinical diagnoses that were made by dermatologists,general practitioners,family physicians, and other specialties were then correlated with the final histopathologic diagnoses.The investigators reported that dermatologists achieved diagnostic accuracy of 24.75%, general practitioners and family physicians achieved 3.52%, and all other specialists achieved 12.7%.

Early detection critical to outcome “The majority of patients with suspicious skin lesions present to family physicians or general practitioners first,” the authors wrote. “Thus there is considerable value in providing more training and education to non-dermatologists because it can have a meaningful impact on patient care.”

Dr. Shannon Humphrey Dermatologist

Study author Dr. Shannon Humphrey, clinical assistant professor and the director of continuing medical education in the Department of Dermatology & Skin Science at the University of British Columbia in Vancouver, said she was interested in assessing the ability of physicians to accurately diagnose melanoma because “it has been recognized again and again that early detection is the key to improve outcomes of patients, [and] early detection is dependent on diagnostic accuracy.”

The results of the study, according to Dr. Humphrey, were not unexpected. “We know that [family physicians and general practitioners] get little if any clinical dermatology training in medical school and even less in their family practice residency,” she said. “I think it is likely that they adopt a ‘better safe than sorry’ approach where they would biopsy more lesions to try to cast the net wide if you will and not miss any melanoma, and this results in a lower diagnostic accuracy.”

Dr. Humphrey said she thinks that a diagnostic accuracy of approximately 25% for dermatologists is a good rate. She said because skin biopsies are an incredibly safe procedure, most dermatologists, if there is any index of suspicion of melanoma, will perform a diagnostic biopsy.

Challenges in melanoma

A challenge to an accurate melanoma diagnosis—and perhaps a uniquely Canadian one—is the lack of access to specialists, noted Dr. Humphrey. There are not enough dermatologists in Canada, she said.Another challenge for physicians is that melanoma has a differential diagnosis—atypical nevi.

“There are patients who are covered in literally hundreds of nevi and it can be quite difficult to pick out the melanoma amidst [that number of] moles,” said Dr. Humphrey.

The researchers suggested that more training and education could improve the diagnostic accuracy of melanoma by non-dermatologists. “I think clinical training is the most useful [form of education] and this is training at the bedside—seeing patient after patient,” said Dr. Humphrey.

“That is the way that pattern recognition is really built and ingrained and it is, unfortunately, the

most difficult type of training to access.”

Shortage of dermatologists

There is a shortage of dermatologists to provide this clinical training, she noted, as well as a shortage of dermatologists to provide clinical education to medical students and family medicine residents.

“We need to come up with a long-term strategy as physicians to improve the diagnostic accuracy of non-dermatologists,” Dr. Humphrey told DERM.city. “Particularly because there [is no] short-term solution to the dermatologist manpower shortage.”

The researchers hope that the study brings to the forefront the critical importance regarding the early detection of melanoma. Also, they aimed to highlight that not all physicians have the same diagnostic skill and accuracy.

“In a particularly high risk patient or [for] a particularly suspicious lesion, it [is] reasonable and warranted to find a dermatologist to provide care,” concluded Dr. Humphrey.

Originally published in the The Chronicle of Skin & Allergy (Mar. 2016; 22(2):1,6).


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