Skin Cancer

What is Skin Cancer?

Skin cancer arises when skin cells undergo genetic mutations that disrupt normal cellular regulation, leading to uncontrolled growth. It is one of the most common forms of cancer globally, yet also one of the most treatable when identified early.

At a cellular level, these changes occur when DNA within skin cells is damaged, most commonly by ultraviolet (UV) radiation. This damage alters the cell's ability to regulate division and repair, allowing abnormal cells to persist and multiply.

While the term cancer is often associated with systemic disease, many skin cancers remain localised and highly manageable when approached through early detection and appropriate medical treatment. Skin cancer should be understood not as an isolated event, but as a consequence of cumulative biological damage over time.

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What are the Types of Skin Cancer?

Skin cancers are classified according to the cell type in which the mutation originates. The three principal forms are:

1. Basal Cell Carcinoma (BCC) - The most common form, arising from basal cells in the lower epidermis. Clinically, it often presents as a pearly or translucent lesion, sometimes with visible blood vessels or a tendency to bleed and crust. While slow-growing and unlikely to metastasise, it can cause significant local tissue damage if left untreated.
2. Squamous Cell Carcinoma (SCC) - Originating from squamous cells within the epidermis, this form tends to be more aggressive than BCC. It may present as a firm nodule or a scaly, crusted patch that does not resolve. SCC carries a higher risk of spreading, particularly when diagnosis is delayed.
3. Melanoma - A less common but more serious form, arising from melanocytes, the pigment-producing cells. Melanoma often presents as a new or changing mole. Clinical assessment frequently follows the ABCDE criteria: asymmetry, border irregularity, colour variation, diameter, and evolution over time. It has a greater potential for invasion and systemic spread, making early detection critical.

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What Causes Skin Cancer?

The primary driver of skin cancer is exposure to ultraviolet radiation, which induces direct DNA damage within skin cells. Over time, this damage accumulates, overwhelming the skin's natural repair mechanisms. Mutations in genes responsible for cell growth and regulation allow abnormal cells to proliferate unchecked.

Patterns of exposure influence the type of cancer that develops:

• Cumulative exposure is more closely associated with basal and squamous cell carcinomas
• Intermittent, intense exposure, particularly resulting in sunburn, is strongly linked to melanoma

Additional factors, including genetic predisposition, lighter skin types, and immunosuppression, further influence susceptibility. A visible tan represents a biological response to DNA injury. The absence of burning does not equate to the absence of damage.

Skin cancer develops through a combination of environmental exposure and individual susceptibility:

• Ultraviolet (UV) radiation - From natural sunlight or artificial sources such as tanning devices
• Cumulative sun exposure - Particularly relevant for non-melanoma skin cancers
• Intermittent intense exposure - Including episodes of sunburn, especially earlier in life
• Skin type - Individuals with lighter skin have reduced natural protection against UV damage
• Genetic and immune factors - Family history and reduced immune surveillance increase risk

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How is Skin Cancer Treated?

Management is determined by the type, size, location, and stage of the lesion, with the primary objective being complete removal while preserving healthy tissue.

1. Surgical Excision - Standard treatment for most skin cancers. The lesion is removed along with a margin of surrounding tissue to ensure complete clearance.
2. Mohs Micrographic Surgery - A highly precise technique, particularly suited to cosmetically sensitive areas. Tissue is removed in stages and examined immediately, allowing maximal preservation of healthy skin with high cure rates.
3. Topical and Field Therapies - Used in selected cases, particularly for superficial lesions or pre-cancerous changes. These treatments stimulate local immune response or directly target abnormal cells.
4. Systemic Therapy - For advanced or metastatic disease, particularly melanoma, treatment may involve targeted therapies or biologic agents that modulate the immune system.

Prevention remains central to long-term skin health:

• Broad-spectrum sunscreen - Daily use of SPF 50+ with protection against both UVA and UVB
• Physical protection - Clothing, hats, and shade provide consistent and reliable defence
• Behavioural measures - Avoidance of peak sun exposure and tanning practices
• Regular skin surveillance - Professional skin examinations support early detection of changes

A proactive, prevention-focused approach combined with early clinical evaluation remains the most effective strategy for long-term management.