9th July 2023

Non-Melanoma Skin Cancer (NMSC)

Basal Cell Carcinoma (BCC)

The most common form of skin cancer which generally has a good prognosis due to its slow local invasion and infrequent metastasis. Risk factors include prolonged and cumulative UV exposure on sun-exposed sites, fair skin, and previous solar damage such as AKs. Biopsy confirms the histological subtype and informs management. Nodular BCC is the most common. Most BCCs are treated surgically, such as by excision, Mohs micrographic surgery (lesions that are high risk, recurrent or if sited on areas of cosmetic concern), curettage and cautery, and cryotherapy. Non-surgical treatments include topical creams such as 5-FU (cytotoxic agent) and Imiquimod (immunomodulating agent), PDT and radiotherapy.

Table 1: Three different types of BCCs with associated descriptions and treatment options.

Nodular BCC with overlying telangiectasia sited on the nasolabial fold.

Image Source: Wikimedia Commons (2017). Basal-cell Carcinoma, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Basal-cell_Carcinoma.jpg (Accessed on: 3 November 2021).

Squamous Cell Carcinoma (SCC)

SCC risk factors are similar to BCCs, but also include a background of Bowen’s disease (SCC in-situ), chronic ulcers (leading to a Marjolin ulcer), smoking, HPV infections and immunosuppression. Presentation is often of a rough or scaly papule/plaque that may bleed and later ulcerate. SCCs are more aggressive than BCCs, with a greater potential to metastasise, requiring a 2WW referral. Lesion size informs the full-thickness biopsy margin:

• Low-risk lesion: ≤20mm: ≥4mm margins
• High-risk lesion: >20mm: ≥6mm margins

Biopsy confirms diagnosis, assesses histological margins and level of differentiation. This informs management and prognosis. Invasive SCCs penetrate beyond the basement membrane, for which further body imaging should be considered, e.g. CT, MRI.

Table 2: SCC types with potential treatment options

Bowen’s disease on the finger. 

Image Source: Wikimedia Commons (2009). Bowen11, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Bowen11.jpg (Accessed on: 3 November 2021).