Skin Cancer

Medically reviewed by NCIS Specialists. Last reviewed by A/Prof Peter Goon. Published on 31 October 2026.

What is skin cancer?

The skin is the body's largest organ and serves predominantly as a protective barrier against environmental elements. It is made up of three main structural layers:

Epidermis — The outermost layer, composed mainly of squamous cells, basal cells, and melanocytes (cells producing the skin pigment melanin).

Dermis — The middle layer that contains collagen, blood vessels, lymph vessels, hair follicles, and various glands.

Subcutis (subcutaneous tissue) — The deepest layer, made up of fat, vessels, and connective tissue.

Skin cancer can be defined as the uncontrolled growth of certain skin cells that can invade surrounding healthy tissues or spread to other parts of the body.

The three most common types of skin cancer are basal cell carcinoma, squamous cell carcinoma, and melanoma. These abnormal skin cells can also present as pre-cancers, which raises the importance of early detection and treatment.

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What are the signs & symptoms of skin cancer?

Skin cancer usually arises on sun-exposed skin, including the scalp, face, lips, ears, neck, chest, arms, and hands. However, other non-exposed areas can be affected, including the soles, beneath the fingernails or toenails, and even the genital area. Some of these cancers can develop insidiously and may be mistaken for moles or age spots.

Basal cell carcinoma

Basal cell carcinoma usually occurs in sun-exposed areas of the skin like the face. It may appear as:

• A flat, flesh-coloured or brown scar-like lesion
• A pearly or waxy bump
• A bleeding or scabbing sore that does not heal

Squamous cell carcinoma

Squamous cell carcinoma occurs commonly on sun-exposed areas of your body, such as the scalp, face, ears, neck, and hands. Patients with a history of organ transplant or taking medications to lower their immune system are at higher risk of squamous cell carcinoma. It may appear as:

• A patch of red rash or scaly crusted area that does not go away
• A firm, red nodule
• A bleeding ulcer or bump

Melanoma

Melanoma can develop anywhere on your body. In Asians and people of darker skin tones, melanoma tends to occur on the palms or soles, or under the fingernails or toenails. They usually arise as a new mole in adulthood and less commonly in an existing mole that becomes cancerous. Melanoma may appear as:

• A mole that changes in colour, size, or feel, or that bleeds
• A small lesion with an irregular border and portions that appear red, pink, white, blue, or blue-black
• Dark lesions on the palms, soles, fingertips, or toes, or on mucous membranes lining the mouth, nose, or genital area
• A large brownish spot with irregular borders
• A painful lesion that itches or burns

A doctor should be consulted if the above symptoms occur.

How should I monitor my skin for skin cancer?

You can use the ABCDE rule for monitoring your skin for signs of skin cancer. Consult your dermatologist immediately if any of your moles or pigmented spots exhibit:

• Asymmetry — if one half of the spot is unlike the other half.
• Border — if the spot has an irregular, scalloped, or blurred border.
• Colour — if the spot has varying colours, including different shades of brown, or even red, blue, or white.
• Diameter — if the mole has a diameter larger than 6mm.
• Evolution — changes in colour, shape, or thickness of the spot, or development of new signs including pain, itch, crusting, or bleeding.
  
  

What are the risk factors of skin cancer?

Patient factors

• Family and personal history of skin cancer
• Older age
• Fair skin
• Certain rare inherited conditions
• Presence of abnormal moles (dysplastic nevi)

Acquired factors

• History of UV (ultraviolet) exposure such as sun tanning and sunburns
• Environmental exposure to certain carcinogens, chemicals, or ionising radiation
• Immunosuppression or use of long-term immunosuppressive agents
  
  

What can you do to prevent skin cancer?

While there is no guaranteed way to prevent skin cancer, adopting appropriate lifestyle habits can reduce the risk and support overall well-being:

• Avoid going out in the midday sun, particularly between 9am and 4pm.
• Apply broad-spectrum sunscreen or wear adequate sun protection clothing.
• Avoid tanning beds.
• Find out about your family history of skin cancer.
• Perform regular skin self-examinations for any new or suspicious lesions.
• Attend medical screening examinations where appropriate.
  
  

How is skin cancer diagnosed?

Skin cancer is detected through a combination of the following:

Medical history and physical examination

Your dermatologist will ask about your personal and family history of skin cancer and examine your skin for any abnormal spots, moles, or lesions. The shape, size, colour, and texture of the suspicious area will be assessed.

Dermoscopy

A dermatoscope (a handheld magnifying device) may be used to take a closer look at the lesion. This tool helps the doctor visualise structures beneath the skin's surface and determine whether the lesion has features of skin cancer.

Biopsy

If the spot appears suspicious, your dermatologist will remove all or part of the area for laboratory testing. A biopsy involves taking a small skin sample and examining it under a microscope to look for cancer cells. Common types of biopsies include a punch biopsy, where a circular tool is used to remove a small core of tissue, and an excisional biopsy, where the entire lesion is removed for testing. Your doctor will explain the procedure and what to expect before it is performed.

What are the treatment options for skin cancer?

There are different treatments available for skin cancer depending on the stage, the position of the cancer, and your overall health. The three main types of treatment include surgery, radiation, and chemotherapy. Certain early cancers or pre-cancers may be treated by locally ablative procedures.

[Stage 0] Cancer is limited to the outermost layer of skin (epidermis).

• Topical treatments (e.g., 5-fluorouracil or imiquimod cream)
• Cryotherapy — freezing the lesion with liquid nitrogen
• Curettage and desiccation — scraping off the cancer followed by electric cauterisation
• Photodynamic therapy (PDT) — uses light-sensitive drugs activated by light
• Surgical excision — especially if topical treatments are not effective

[Stage 1] Cancer is localised and small (≤2 cm), without high-risk features.

• Wide local excision — surgical removal with adequate margins
• Mohs Micrographic Surgery (MMS) — layer-by-layer removal with microscopic examination, ideal for areas requiring tissue preservation such as the face
• Cryotherapy or curettage and desiccation may be considered for superficial basal cell carcinoma (BCC) or squamous cell carcinoma in situ

[Stage 2] Larger or high-risk local tumours (e.g., >2 cm, poorly differentiated).

• Surgical excision with wider margins
• Mohs surgery for facial or high-risk lesions
• Radiation therapy may be added if surgery is not an option or if margins are unclear
• Skin flap or graft reconstruction may be needed post-surgery

[Stage 4] Cancer has spread to nearby lymph nodes or underlying tissues..

• Surgery to remove the primary tumour and affected lymph nodes
• Radiation therapy postoperatively in selected cases
• Targeted therapy or immunotherapy (mainly in melanoma or aggressive squamous cell carcinoma)
• Multidisciplinary team management is crucial

[Stage 5] Metastatic skin cancer (spread to distant organs).

• Systemic therapies including:
  • Immunotherapy (e.g., checkpoint inhibitors like pembrolizumab or nivolumab for advanced melanoma)
  • Targeted therapy (e.g., BRAF/MEK inhibitors in melanoma with BRAF mutations)
• Radiation therapy to control symptoms
• Palliative care for symptom relief and quality-of-life support

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What is post-treatment for skin cancer?

After treatment for skin cancer, regular follow-up and self-care are essential to monitor for recurrence, manage scarring or side effects, and prevent future skin cancers.

Regular dermatology follow-ups

You will need routine skin checks with your dermatologist, especially in the first few years after treatment. These visits may include full-body skin examinations, monitoring of scars and treated areas, and assessment of any new or changing skin lesions. Follow-up frequency is typically every 3–12 months depending on your cancer type (e.g., melanoma vs non-melanoma).

Self skin-examinations

Check your skin monthly for new growths or moles, changes in colour, size, or shape, persistent sores that do not heal, and spots that bleed, itch, or crust over. Use a mirror or ask a loved one to help examine hard-to-see areas like your back or scalp.

Scar and skin management

• Follow wound care instructions after surgery or topical treatments.
• Use moisturisers or silicone-based gels for scar care.
• Protect scars from sun exposure to reduce darkening.

Sun protection

To reduce the risk of recurrence or developing new skin cancers:

• Apply broad-spectrum sunscreen (SPF 30 or higher) daily.
• Wear protective clothing, wide-brimmed hats, and sunglasses.
• Avoid sun exposure between 10am and 4pm.
• Never use tanning beds or sunlamps.

Emotional well-being and support

• Join a skin cancer support group if you feel isolated or anxious.
• Speak with a counsellor if you are struggling with body image concerns or fear of recurrence.
• Stay active and connected to support a positive recovery.