Evaluating the Diagnostic Accuracy of Reflectance Confocal Microscopy to Diagnose Skin Cancer: A Research Protocol (Preprint)

UNSTRUCTURED Skin cancer is the most common type of cancer in the UK, with over 100,000 cases diagnosed each year. Melanoma is a type of skin cancer that can develop from a mole. However, moles that are suspicious histologically are often difficult to diagnose clinically by eye, even for experts working in specialist skin cancer screening clinics. In the UK, 350,000 patients per year are referred to hospital clinics with suspicious moles, and approximately half undergo a biopsy to identify the 5-10% who require further treatment. If cancer cannot be ruled out clinically and on the basis of biopsy results, the lesion is surgically removed. One type of pre-cancerous mole, called lentigo maligna, is particularly challenging to treat. It develops insidiously, can become large, and is difficult to assess when it transforms into a lentigo maligna melanoma. It is also difficult to identify the margins by eye or with the aid of a dermatoscope. This results in high excision rates. Excision is often incomplete despite large areas of tissue removal (5 mm around tumour’s visible margin), and there are high recurrence rates even when the lesion is considered successfully removed. Reflectance confocal microscopy is an imaging technique that can supplement dermoscopy in identifying if a clinically suspicious mole is malignant and can better assess lentigo maligna margins. It allows clinicians to see the skin lesion in greater detail than dermoscopy and therefore better guide more accurate diagnoses. This prospective study will examine patients with suspicious moles and lentigo maligna to determine whether confocal microscopy can both reduce the number of unnecessary biopsies of moles and more accurately guide the surgical excision margins of lentigo maligna.