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Specialized clinics improved in accurately detecting melanoma

Using number-needed-to-excise values, researchers conducting a 10-year study found that accuracy in melanoma detection improved in specialized clinics but remained stable in nonspecialized clinics.

Twenty-one clinical centers and two dermatology units from 13 countries participated in the study. The survey compared number-needed-to-excise (NNE) values between 1998 and 2007 at the clinics. The NNE value was calculated by dividing the total number of excised lesions by the number of melanomas.

Study recruitment included specialized and nonspecialized clinics. A specialized clinical setting (SCS) was defined as a clinic dedicated to the management of skin cancer. A nonspecialized clinical setting (NSCS) was defined as a clinic not dedicated specifically to skin cancer, where a primary care physician, a dermatologist or other specialist might treat patients with various conditions.

The researchers studied 300,215 histopathologically confirmed cases, including 17,172 melanomas and 283,043 melanocytic nevi. During the 10-year period, the overall NNE values achieved in SCS and NSCS were 8.7 and 29.4, respectively.

The diagnostic assessment by NNE for the SCS improved during the study from 12.8 to 6.8 for a yearly reduction of 0.6 (95% CI, 0-4.-0.7). In 1998, there were 596 excised melanomas and 7,023 melanocytic nevi compared with 1,540 excised melanomas and 9,005 melanocytic nevi in 2007.

During the same period, the change in NNE score for NSCS was minimal, going from 31.9 to 28.5 (P=.45). In 1998, there were 650 excised melanomas and 20,067 excised melanocytic nevi. In 2007, 750 melanomas and 20,659 melanocytic nevi were excised.

Researchers said the increase in melanoma excisions in the SCS could be the result of screening individuals with a higher incidence of melanoma than the general population and the expanded use of dermatoscopy.

“The use of dermatoscopy can improve the accuracy in melanoma detection as measured by NNE values,” the researchers said. “Incorporation of this diagnostic technique in clinical practice should be expanded, not only to improve melanoma detection but also to decrease the excision rate of benign lesions, especially in younger patients.”