Skin Cancer

Introduction | Types of Skin Cancer | Clinical Presentation | Diagnosis | Management and Referral | References

Introduction

Skin cancer is one of the most common types of cancer, particularly in fair-skinned individuals. The three major types of skin cancer are Basal Cell Carcinoma (BCC), Squamous Cell Carcinoma (SCC), and Melanoma. While BCC and SCC are often referred to as non-melanoma skin cancers and typically have a good prognosis, melanoma is more aggressive and can be life-threatening if not detected early. Early detection and appropriate management are crucial for optimal outcomes.

Types of Skin Cancer

1. Basal Cell Carcinoma (BCC)

Basal Cell Carcinoma (BCC) is the most common type of skin cancer, originating from the basal cells in the epidermis. It is usually slow-growing and rarely metastasises, but can cause significant local tissue damage if not treated.

• Common Sites: BCC most frequently occurs on sun-exposed areas, particularly the face, ears, neck, and upper chest.
• Risk Factors: Chronic sun exposure, fair skin, history of sunburns, and increasing age are the primary risk factors.

2. Squamous Cell Carcinoma (SCC)

Squamous Cell Carcinoma (SCC) arises from the keratinocytes in the epidermis. It is the second most common type of skin cancer and has a higher potential for metastasis compared to BCC.

• Common Sites: SCC commonly occurs on sun-exposed areas like the face, ears, hands, and lower lip. It can also develop in chronic wounds or areas of chronic inflammation.
• Risk Factors: Chronic sun exposure, fair skin, immunosuppression, and certain pre-cancerous conditions such as actinic keratosis.

3. Melanoma

Melanoma is a malignant tumour that originates from melanocytes, the cells responsible for producing pigment in the skin. Melanoma is less common than BCC and SCC but is far more aggressive and has a higher risk of metastasis.

• Common Sites: Melanoma can develop anywhere on the body, including areas not typically exposed to the sun. It often appears on the back in men and the legs in women.
• Risk Factors: Risk factors include a history of intense, intermittent sun exposure, fair skin, numerous moles, family history of melanoma, and previous melanoma.

Clinical Presentation

The clinical features of BCC, SCC, and melanoma can help differentiate these skin cancers:

1. Basal Cell Carcinoma (BCC)

• Pearly Nodules: BCC often presents as a pearly or translucent nodule with telangiectasia (small visible blood vessels).
• Ulceration: It may ulcerate centrally, forming a "rodent ulcer" with a rolled border.
• Flat, Scar-Like Lesion: Superficial BCC may appear as a flat, scar-like, or erythematous plaque.

2. Squamous Cell Carcinoma (SCC)

• Scaly, Crusted Lesion: SCC typically appears as a scaly, red, or crusted lesion that may be tender or bleed easily.
• Thickened Plaque or Nodule: It may present as a thickened, firm plaque or nodule, sometimes with a wart-like surface.
• Ulceration: SCC lesions may ulcerate and have an indurated (hardened) base.

3. Melanoma

• ABCDE Rule: Melanoma is often identified by the ABCDE criteria:
  • Asymmetry: One half of the mole doesn't match the other.
  • Border: The edges are irregular, ragged, or blurred.
  • Colour: The colour is not uniform and may include shades of brown, black, red, white, or blue.
  • Diameter: Melanomas are usually larger than 6mm, but they can be smaller when diagnosed.
  • Evolving: The mole is changing in size, shape, or colour.
• Nodular Melanoma: This subtype may not follow the ABCDE rule and presents as a rapidly growing, dome-shaped nodule that can be blue-black, pink, or red.
• Acral Lentiginous Melanoma: A subtype found on the palms, soles, or under the nails, more common in people with darker skin.

Diagnosis

Diagnosis of skin cancer involves a combination of clinical examination and biopsy:

• Dermatoscopy: A dermatoscope can be used to examine pigmented lesions in more detail, helping to identify suspicious features of skin cancer.
• Skin Biopsy: A definitive diagnosis is made by taking a biopsy of the lesion, which is then examined histologically. Types of biopsy include:
  • Shave Biopsy: Often used for BCC or SCC where the lesion is superficial.
  • Excisional Biopsy: Preferred for suspected melanoma to remove the entire lesion with a margin of normal skin.
  • Punch Biopsy: May be used to sample part of a larger lesion.
• Histopathology: The biopsy is examined to determine the type of skin cancer, its depth, and other features that guide treatment.

Management and Referral

The management of skin cancer depends on the type, size, location, and depth of the tumour. Referral guidelines differ based on these factors:

1. Basal Cell Carcinoma (BCC)

• Management: BCC is usually treated with surgical excision. Superficial BCC may be treated with topical therapies such as imiquimod or fluorouracil, or with cryotherapy.
• Referral: BCCs generally do not require a 2-week wait (2WW) referral. However, referral to dermatology is recommended for complex cases, such as large, recurrent, or high-risk BCCs (e.g., near critical structures like the eyes or nose).

2. Squamous Cell Carcinoma (SCC)

• Management: SCC is typically treated with surgical excision, with a wider margin than BCC. For high-risk or recurrent SCC, Mohs surgery may be used. Radiotherapy is an option for patients who are not surgical candidates.
• Referral: SCC should be referred under the 2-week wait (2WW) pathway due to its potential to metastasise, particularly for lesions on the lip, ear, or in immunosuppressed patients.

3. Melanoma

• Management: Melanoma requires surgical excision with wide margins. The size of the margin depends on the Breslow thickness of the tumour. Sentinel lymph node biopsy may be considered for staging in thicker melanomas.
• Referral: Suspected melanoma must be referred under the 2-week wait (2WW) pathway due to its high risk of metastasis. Early detection and treatment are crucial for improving prognosis.

Summary of Referral Guidelines:

• BCC: Routine referral to dermatology; does not typically require a 2WW referral unless complex or high-risk.
• SCC: 2WW referral is recommended due to the risk of metastasis.
• Melanoma: Always requires a 2WW referral due to the high risk of metastasis and need for early intervention.

References

1. National Institute for Health and Care Excellence (2024) Guidelines for the Diagnosis and Management of Skin Cancer. Available at: https://www.nice.org.uk/guidance/ng14 (Accessed: 26 August 2024).
2. British Association of Dermatologists (2024) Skin Cancer Treatment and Referral Guidelines. Available at: https://www.bad.org.uk (Accessed: 26 August 2024).
3. British National Formulary (2024) Medications and Treatments for Skin Cancer. Available at: https://bnf.nice.org.uk/ (Accessed: 26 August 2024).