Basal cell carcinoma

Basal cell carcinoma, also known as rodent ulcer, is defined as a slow-growing, locally invasive, malignant epidermal skin cancer, which predominantly affects white people and is rare in people with dark skin (Tidy, 2021). Skin cancers are generally classified as either melanoma or non-melanoma and basal cell carcinoma is the most common non-melanoma type, with approximately 75 000 new cases diagnosed in the UK each year (National Institute for Health and Care Excellence, 2024). The incidence of basal cell carcinoma rises significantly after the age of 40 years, but there has been a recent increase in cases among younger age groups, especially women, which has been attributed to a greater exposure to the sun or the use of tanning beds (Dika et al, 2020). 

Basal cell carcinoma can develop anywhere on the skin, but most frequently occurs on areas exposed to the sun, such as the face, head, neck and arms. Of these sites, around 80% of lesions occur on the head and neck, with the rest mainly on the trunk and lower limbs, particularly in women (Wong et al, 2003). Increasing age is a key risk, in addition to several other factors (Table 1). 

The underlying aetiology of basal cell carcinoma is highly complex, and is attributed to a hedgehog intracellular signalling pathway (Campione et al, 2020). This is a signalling pathway that transmits information to embryonic cells and is now known to be essential for tissue repair, maintenance and differentiation of stem cells (Campione et al, 2020). Any disruption or malfunction to this pathway is associated with the development of basal cell carcinoma (Campione et al, 2020). Excessive exposure to sun and ultraviolet radiation causes damage to the DNA and a dose-dependent suppression of the cutaneous immune system, leading to impaired immune surveillance of skin cancer (McDaniel et al, 2024). A popular hypothesis is that basal cell carcinoma arises from basal keratinocyte stem cells that lie between hair follicles of the dermal-epidermal junction and in the bulge of the hair follicle, and that unregulated cell growth among these stem cells leads to tumour

Diagnosis is largely made on history and clinical examination, but sometimes a skin biopsy may be needed if there is any doubt in the diagnosis (Nambudiri, 2023). Dermoscopy may also be beneficial in making the diagnosis, but this is not available in all practices (National Institute for Health and Care Excellence, 2024). 

There are now several treatment options for basal cell carcinoma, and the choice will depend on the patient’s age and health status, as well as the type, size and site of the tumour. The aim of treatment is to completely remove the lesion, prevent its recurrence in the future and to give the best possible cosmetic appearance on completion of treatment, particularly for tumours excised from the face. Available treatments are divided into two categories (Brass and Rajan, 2013), surgical and non-surgical: 

Surgical treatments