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Rates of melanoma, the deadliest form of skin cancer, have been rising for at least the last three decades, and this increase has been largely blamed on exposure to ultraviolet (UV) light from the sun.
However, research published in the British Journal of Dermatology shows that the sun is likely nothing more than a scapegoat in the development of melanoma, and the sharp increase may actually be “an artifact caused by diagnostic drift.”
Melanoma Increases Due to Benign Disease, Not Sunlight
Diagnostic drift, according to the study, refers to a hefty increase in disease that is being fueled by non-cancerous lesions.
In fact, during the study period from 1991 to 2004, there were nearly 4,000 cases of melanoma included in the report, with an annual increase of 9.39 to 13.91 cases per 100,000 per year.
The researchers revealed that, rather than being fueled by increasing exposure to sunlight as is commonly suggested, the increased incidence was almost entirely due to minimal, stage 1 disease.
“There was no change in the combined incidence of the other stages of the disease, and the overall mortality only increased from 2.16 to 2.54 cases per 100,000 per year … We therefore conclude that the large increase in reported incidence is likely to be due to diagnostic drift, which classifies benign lesions as stage 1 melanoma.”
In other words, people are being diagnosed with melanoma skin cancer even when they have only a minimal, non-cancerous lesion, and these diagnoses appear to be skewing disease rates significantly. Further, adding even more credence to the growing body of evidence showing sun exposure is not the primary cause of melanoma, the researchers noted that the distribution of the lesions reported did not correspond to the sites of lesions caused by sun exposure.
“These findings should lead to a reconsideration of the treatment of ‘early’ lesions, a search for better diagnostic methods to distinguish them from truly malignant melanomas, re-evaluation of the role of ultraviolet radiation and recommendations for protection from it, as well as the need for a new direction in the search for the cause of melanoma.”