Skin cancer

Skin cancer develops when cells in the skin are damaged – most often by UV radiation from the sun or sunbeds – and start to divide uncontrollably. That is why skin cancer most often appears where the skin has had the most sun: the face, ears, scalp, neck and hands.

A distinction is made between non-melanoma skin cancer – basal cell carcinoma and squamous cell carcinoma – and melanoma (malignant melanoma), which is less common but more serious. Actinic keratosis is a precursor that can develop into squamous cell carcinoma.

• Basal cell carcinoma
• Squamous cell carcinoma
• Actinic keratosis
• Melanoma

Read more about skin cancer where it most often appears: skin cancer of the scalp and skin cancer on the face, ear and lip.

See the different types of skin cancer →

Non-melanoma skin cancer can appear anywhere on the body, but the vast majority of cases are on the head and neck. Often it is a sore that won't heal, or a lump that bleeds or weeps. An experienced dermatologist will usually recognise skin cancer easily, but it can be mistaken for a harmless skin condition.

See pictures of skin cancer →

Basal cell carcinoma is the most common form of skin cancer, and the number of new cases is still rising. According to the Danish Cancer Society (Kræftens Bekæmpelse), there were 12,000 new cases in 2014, evenly split between men and women – a doubling in ten years.

Skin cancer grows slowly. It most often appears on the face, ears, back of the neck and upper chest, but it can occur anywhere on the body. The disease mainly affects older people, but in recent years it has become more common among younger people.

30%

lifetime risk of developing skin cancer.

20%

of all new cases occur in people under the age of 50.

40%

risk of new skin cancer elsewhere on the body if you have had it once.

• Over the past 30 years, the number of cases of skin cancer has tripled among Danish women and more than doubled among Danish men.
• Around 40 people in Denmark are diagnosed with skin cancer every day – more than a whole school class. That is more than 14,600 new cases a year.
• More than 121,000 people in Denmark have been treated for the disease. The real figure is probably twice as high, as many cases are not registered.

The risk of skin cancer increases with age and with how much sun you have had – both outdoors and in sunbeds. That is why skin cancer mainly appears on the areas that get the most sun.

• Fair skin that burns easily in the sun
• Previous radiotherapy
• Intake of arsenic (formerly used to treat psoriasis)
• Long-term contact with carcinogenic substances such as soot and tar
• A weakened immune system or treatment with immunosuppressive medication – in these cases skin cancer appears to develop 10–15 years earlier than normal

If you have been diagnosed with skin cancer once, there is a 40% risk that you will get it again somewhere else on your body. That is why we recommend a yearly check-up with a dermatologist. A full-body skin check is a good way to keep an eye on all of your skin.

Have a doctor look at your skin if you have:

• a sore that does not heal, or that bleeds again and again
• a lump or patch that grows or changes
• a red, scaly patch that does not go away
• a mole that changes in size, shape or colour, or that stands out from the others

Don't wait to see whether it goes away on its own. The earlier skin cancer is found, the easier it is to treat. You can see your GP – or book an appointment directly with one of our specialists, without a referral.

Book an appointment →

The diagnosis is made from a tissue sample, either a biopsy or a scraping (curettage).

Skin cancer destroys the tissue where it grows, but only very rarely spreads to other parts of the body. On the other hand, there is a considerable risk that it will come back after treatment – half of all recurrences are seen within the first three years. The risk depends on the cancer's size, type and location, on the treatment and on the doctor's experience.

Skin cancer can be treated in several ways: curettage and creams, which are used mainly for low-risk tumours; surgery such as Mohs surgery; and radiotherapy.

Mohs surgery gives the greatest certainty that all of the cancer has been removed, and therefore the lowest risk of recurrence. Five years after treatment, the recurrence rate is 1–3% for skin cancer that has not been treated before, and 5–10% for skin cancer that has come back. Mohs surgery is therefore regarded as the gold standard for high-risk basal cell carcinoma on the head and neck, because the method gives the safest and best cosmetic result.

Many people get skin cancer on the ears, nose and around the eyes, where a scar can be bothersome. Because Mohs surgery removes only the tissue that is necessary, the scar is kept as small as possible.

Read also about basal cell carcinoma and squamous cell carcinoma in the Danish Patient Handbook on sundhed.dk, and about non-melanoma skin cancer from the Danish Cancer Society (Kræftens Bekæmpelse).

Sources

• The Danish Cancer Registry (Cancerregistret) 2014. www.sundhedsdatastyrelsen.dk (10 April 2016).
• Miller DL, Weinstock MA. Nonmelanoma skin cancer in the United States: incidence. J Am Acad Dermatol 1994;30:774-8.
• Leman J, McHenry P. Basal cell carcinoma. Arch Dermatol 2001;137:1239-40.
• Diffey BL, Langtry JAA. Skin cancer incidence and the aging population. Br J Dermatol 2005;153:679-80.
• Birch-Johansen F, Jensen A, Mortensen L et al. Trends in the incidence of nonmelanoma skin cancer in Denmark 1978-2007: rapid incidence increase among young Danish women. Int J Cancer 2010;127:2190-8.
• Baxter JM, Patel AN, Varma S. Facial basal cell carcinoma. BMJ 2012;345:e5342.
• Rowe D, Carroll R, Day C. Long-term recurrence rates in previously untreated (primary) basal cell carcinoma: implications for patient follow-up. J Dermatol Surg Oncol 1989;15:315-28.
• Smeets NWJ, Kuijpers DIM, Nelemans P et al. Mohs’ micrographic surgery for treatment of basal cell carcinoma of the face – results of a retrospective study and review of the literature. Br J Dermatol 2004;151:141-7.