Skin Cancer Screening and Mole Check in Singapore

The screening begins with a history of the risk factors that determine how closely each area is examined. These include cumulative sun exposure, previous sunburn, a personal or family history of skin cancer, any mole that has changed, and any sore that has not healed.

The examination covers the entire skin surface. Every mole and every pigmented or scaly patch is assessed under a dermatoscope, a polarised-light magnifier that removes surface glare and shows the pigment network and blood vessel pattern beneath the skin surface. A meta-analysis of clinical studies found that dermoscopy improved diagnostic accuracy for melanoma over naked-eye examination, with the greatest gain among trained examiners. A Cochrane review found that dermoscopy also improves the diagnosis of basal cell carcinoma, although the evidence for squamous cell carcinoma is less certain.

Patients with many moles, or with a mole that warrants surveillance rather than removal, also have mole mapping at the first visit, which adds about 15 minutes.

Each screening concludes with a management plan. For most patients the plan is reassurance and an interval for the next examination, and for some it is excision of a specific mole. Where the clinical finding is clear, the biopsy is taken at the same visit.

The ABCDE rule is the most widely used checklist for melanoma. Its five criteria are Asymmetry, an irregular Border, more than one Colour, a Diameter above 6 mm, and Evolution, meaning any change in size, shape, colour or symptoms. Evolution was added to the original ABCD criteria in 2004, because a changing mole is among the strongest warning signs and some melanomas are detected while still smaller than 6 mm.

The ugly duckling sign is the second rule. Moles on the same person tend to resemble one another, so a mole that differs from the rest warrants examination whatever its ABCDE score. In a prospective study of skin examinations by dermatologists, the ugly duckling sign was a major contributor to the efficiency of melanoma detection.

Non-melanoma skin cancers are easily missed because they often do not resemble a typical mole. Basal cell carcinoma usually presents as a pearly or skin-coloured bump, often with fine surface vessels, which bleeds, crusts, appears to heal and then breaks down again. In Asian skin, basal cell carcinoma is frequently pigmented and can be mistaken for a benign mole, so every pigmented lesion is assessed under dermoscopy rather than by eye. Squamous cell carcinoma usually presents as a firm, scaly or crusted lump, or a persistent rough red patch, on the face, ears, scalp, forearms or hands. Any sore that has not healed within six weeks should be examined.

A lesion that looks suspicious is discussed at the same visit and the next step is planned there. For most lesions that step is excision, in which the whole mole is removed with a small margin of normal skin under local anaesthetic and sent for histology. For larger lesions, or where the diagnosis will determine the extent of surgery, a small biopsy is taken first.

I perform the surgery as a day surgery case in an MOH approved ambulatory surgery centre, so it is claimable under day surgery insurance, subject to your policy. Histology is reported through my practice’s collaboration with Singapore General Hospital, whose pathology service returns each report in two to three weeks. A benign report concludes the episode, whereas a skin cancer report is explained in terms of the type of cancer, the margin status and the treatment plan. Where a wider excision is needed, it is performed by our in-house plastic surgeon as a day surgery case.

Laser is never used on a mole that has not been assessed as benign under the dermatoscope, because laser destroys the tissue and leaves no specimen for histology. The mole check therefore precedes any cosmetic mole removal.