Squamous cell carcinoma

Squamous cell carcinoma is a malignant tumour arising from the keratinising cells of the epidermis and its appendages (Tidy, 2021). Squamous cell carcinoma is a non-melanoma type of skin cancer, and is the second most common skin cancer, with an increasing incidence worldwide (Combalia and Carrera, 2020). The prevalence is higher in white people and is more common in men, with the number of cases rising with increased age (Combalia and Carrera, 2020).

The appearance of squamous cell carcinoma varies, but is usually characterised by the thick scaly appearance of the affected area of skin (Nambudiri, 2024). Lesions commonly occur on areas of the body that are exposed to the sun (often on the head and neck) and may manifest as a small nodule which becomes necrotic and sloughs, developing into an ulcerated lesion with hard, raised edges (Tidy, 2021). Patients may seek medical advice when the lesion does not heal, raising the concern to both the patient and clinician that there may be something more serious going on.

The aetiology of squamous cell carcinoma is multifactorial and involves environmental, immunological and genetic factors. However, ultraviolet radiation exposure (both sun and tanning beds) is the most prominent risk factor for the development of the condition (Hadian et al, 2024). It is derived from cells within the epidermis that produce keratin, a horny protein that makes up skin, hair and nails (Whittaker and Oakley, 2024). Genetic mutations also play a key role; mutations in the p53 gene are the most frequently occurring genetic abnormalities found across several conditions, including:

• actinic keratosis
• squamous cell carcinoma
• invasive squamous cell carcinoma (Hadian et al, 2024)

The p53 protein prevents the replication of cells with mutated DNA from multiplying, so if the p53 gene becomes damaged and is unable to function correctly, this allows cells with damaged DNA to replicate, leading to the development of squamous cell carcinoma (Hadian et al, 2024). Bowen's disease

Initial patient assessment should include a thorough history and questions relating to foreign travel, the amount of previous sun exposure and use of sunbeds. Family history should also be assessed to determine previous treatment for skin cancers among other family members. Physical examination of the patient’s skin may reveal excessive skin wrinkling, characterised as more wrinkles than would normally be likely for the patient’s age. In addition, sunspots are useful indicators of excessive sun exposure and damage. Skin colour should also be assessed, as those with fair skin are at a higher risk of squamous cell carcinoma (Newlands et al, 2016).

Following history and examination, National Institute for Health and Care Excellence (2024) guidelines suggest referral within 2 weeks for any patient with a lesion that raises suspicion of squamous cell carcinoma. A biopsy done under local anaesthetic will confirm the diagnosis. For larger lesions, those close to vital structures

There are many treatment options available for patients with squamous cell carcinoma, but decisions may be influenced by several factors, including:

• the lesion itself (size and thickness)
• the equipment available
• patient factors (eg general health, immunosuppression or potential for poor wound healing at sites such as the lower leg)

Consideration should also be given to the patient’s previous experience of treatment and cosmetic awareness (Sharma et al, 2023), but surgical excision remains the gold standard and first-line option. Conventional excision must ensure complete removal and include a margin of clinically normal-appearing skin around the tumour and surrounding erythema (Combalia and Carrera, 2020). Mohs surgery (a specialised treatment that involves excising the cancer in thin layers) is recommended in cases of high-risk squamous cell carcinoma, for immunocompromised patients or where the growth is at sites where tissue conservation is important, such as the head and neck (Prickett and Ramsey, 2023). Characteristics

Nursing and Midwifery Council: standards of proficiency for registered nurses

Part 1: Procedures for assessing people’s needs for person-centred care

1. Use evidence-based, best practice approaches to take a history, observe, recognise and accurately assess people of all ages

2. Use evidence-based, best practice approaches to undertake the following procedures:

2.7 undertake a whole body systems assessment including respiratory, circulatory, neurological, musculoskeletal, cardiovascular and skin status

Sharma A, Birnie AJ, Bordea C et al. British Association of Dermatologists guidelines for the management of people with cutaneous squamous cell carcinoma in situ (Bowen disease) 2022. Br J Dermatol. 2023;188(2):186–194. https://doi.org/10.1093/bjd/ljac042

References

Cancer Research UK. Stages and grades of skin cancer. 2023. https://www.cancerresearchuk.org/about-cancer/skin-cancer/stages-grades (accessed 17 September 2024)

Combalia A, Carrera C. Squamous cell carcinoma: an update on diagnosis and treatment. Dermatol Pract Concept. 2020;10(3):e2020066. https://doi.org/10.5826/dpc.1003a66 

Firnhaber JM. Diagnosis and treatment of basal cell and squamous cell carcinoma. Am Fam Physician. 2012;86(2):161–168

Hadian Y, Howell JY, Ramsey ML. Cutaneous squamous cell carcinoma. Treasure Island (FL): StatPearls Publishing; 2024

Nambudiri VE. Squamous cell carcinoma. 2024. https://www.msdmanuals.com/en-gb/home/skin-disorders/skin-cancers/squamous-cell-carcinoma (accessed 18 September 2024)

National Institute for Health and Care Excellence. Electrochemotherapy for primary basal cell carcinoma and primary squamous cell carcinoma. 2014. https://www.nice.org.uk/guidance/ipg478/chapter/1-recomendations accessed 17 September 2024)

National Institute for Health and Care Excellence. Skin cancers – recognition and referral. 2024.