Skin cancer begins in the skin’s top or outermost layer – the epidermis. The epidermis is a thin layer that provides a protective cover for the body, keeps skin hydrated, produces new skin cells and contains melanin, which determines skin colour. There are three main types of cells in the epidermis:
Skin cancers are divided into melanoma (MSC) and non-melanoma skin cancer (NMSC).
Melanoma skin cancer refers to the malignant tumour of the melanocytes which behaves more aggressively than non-melanoma skin cancers. It can develop anywhere on the body, in otherwise normal skin or in an existing mole that turns cancerous. In Singapore, the incidence of melanoma skin cancer is relatively low with 0.5 cases per 100,000 persons.
Non-melanoma skin cancer refers to all the types of skin cancer that are not melanoma. Non-melanoma skin cancer slowly develops in the upper layers of the skin. The most common types of NMSC are basal cell carcinoma and squamous cell carcinoma.
In Singapore, non-melanoma skin cancer is much more common than melanoma skin cancer. Non-melanoma skin cancer is the 6th most common cancer in males in Singapore and the 7th most common cancer among females in Singapore. Fair-skinned populations are more susceptible to the disease.
Skin cancer develops primarily on areas of sun-exposed skin, including the scalp, face, lips, ears, neck, chest, arms and hands. However, it can also form on areas that are rarely exposed to the sun, such as beneath the palm, fingernails or toenails, and the genital area.
Symptoms of melanoma skin cancer may include:
Symptoms of non-melanoma skin cancers may include:
When to see a doctor
Make an appointment with your doctor if you notice any changes to your skin that worry you.
Most skin cancers are preventable. There are several ways to lower the risk of skin cancer:
Excessive ultraviolet (UV) radiation from the sun (i.e. sun exposure) is the most important risk factor of skin cancers. Tanning, including exposure to tanning lamps and beds, also increases the risk of skin cancer.
Other risk factors include:
Tests and procedures used to diagnose skin cancer include:
In some cases, skin cancer can be diagnosed and treated at the same time. The tumour is removed and tested and you may not need further treatment if the cancer is unlikely to spread.
In other cases, once skin cancer is confirmed, further tests may be needed to determine the extent (stage) of the cancer and the most suitable treatment. The tests may include:
There are a few effective treatment options for skin cancer. In general, treatment for skin cancer depends on the following factors:
The main treatment for skin cancer is surgery. However, some patients may also require other treatments such as chemotherapy, radiotherapy, or cryotherapy.
An individual with cancer should be assessed by a specialist to determine which treatment is best suited for them.
If the skin defect after surgery is large, our surgical oncologists will work with a plastic surgeon to provide reconstructive services to restore a natural appearance. The multidisciplinary team will ensure good oncology treatment and aesthetic reconstruction for best outcomes.
Cryotherapy refers to the use of liquid nitrogen to freeze and destroy pre-cancerous skin lesions (actinic keratosis) and some small early skin cancers. Freezing causes the cancerous tissue to die and form a scab that will naturally fall off in time.
This is a simple and quick procedure used to treat basal cell cancers or thin squamous cell cancers. After removing most of the skin growth, the doctor scrapes away layers of cancer cells using a device with a circular blade (curet). An electric needle is then used to destroy any remaining cancer cells.
When necessary, this procedure may be used in combination with cryotherapy (see above).
Radiotherapy also known as radiation therapy uses powerful energy beams to kill cancer cells. It may be used when the cancer cannot be completely removed during surgery.
For cancers limited to the top layer of skin, creams or lotions containing anti-cancer agents may be applied directly to the skin. Systemic chemotherapy (injected into a vein or taken orally) can be used to treat skin cancers that have spread to other parts of the body.
In patients with advanced skin cancer, chemotherapy may be used alone or with surgery, immunotherapy and radiotherapy.
Photodynamic therapy destroys skin cancer cells with a combination of laser light and drugs that makes cancer cells sensitive to light.
If surgery is required, your surgeon will perform comprehensive medical assessments including blood tests and scans, to see if you are suitable and advise on the risks involved. Your treatment recommendation is often based on consensus by a group of medical specialists' opinions (the tumour board), who come together to discuss the pros and cons of every treatment strategy.
The anaesthesia team will also assess your fitness for surgery and advise you on various aspects of general anaesthesia and pain control after surgery.
Specialist nurses will also provide pre-surgery counselling so that you know what to expect.
After surgery, you will be given regular outpatient appointments to see your team of doctors. During these appointments, you may have blood tests and scans to check if the cancer recurs.
It is important to follow your doctor's advice, keep to your clinic visits and do the recommended scans, so that timely treatment can be administered if the cancer or other problems occur.