Ask the Expert: Skin Cancer

Is it true that skin cancers only develop in areas exposed to the sun e.g. if the back is never exposed we should not be worried about lesions which might appear on this part of the body?

Definitely not – skin cancers can occur at any site in the body including mucous membranes (e.g. lip, conjunctivae, genitals). Basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) occur most commonly in sun-exposed sites (head and neck) with BCC showing preponderance for intermittently sun-exposed areas. (eg back or chest)1. In melanoma, the trunk is the commonest primary site for males and the lower limbs for females2. Apart from sun exposure, other risk factors for development of skin cancers include chemical carcinogens, previous phototherapy/light treatment, radiation, genetic susceptibility, chronic injury and scarring, and immunosuppression3. Early detection of skin cancers is dependent on good awareness of risk factors.

Patients with a new suspicious lesion or a continuing change in an old lesion should seek medical advice, regardless of the site of the lesion.

1. Armstrong BK, Kricker A. (1996) Epidemiology of sun exposure and skin cancer. Cancer Surv;26: 133-53.
2. MacKie RM, Bray C, Vestey J et al. (2007) Melanoma incidence and mortality in Scotland 1979-2003. Br J Cancer. Jun 4;96(11):1772-7.
3. Quinn AG, Perkins W. Non-melanoma sin cancer and other epidermal skin tumours. In: Burns T, Breathnach S, Cox N, Griffiths C (eds) Rook’s Textbook of Dermatology. Volume 3. 8th Ed. Singapore: Wiley-Blackwell; 2010. Chap 52.3-52.12
4. YN Lau, CJ Fleming.

Department of Dermatology, Ninewells Hospital and Medical School, Dundee, Scotland

This article was originally published in the SCPN Newsletter, Volume 4, Issue 3.
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