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Skin cancer – symptoms and treatments

With an area of around 1.8 square meters, the skin is the largest organ in the human body. It fulfills various tasks: It regulates body temperature, activates the immune system, protects the body against water loss and environmental influences such as cold, germs or UV rays. UV rays are, among other things, the most important trigger for all forms of skin cancer.

Types of skin cancer

The term skin cancer refers to various malignant skin tumors. The most common type of skin cancer is white skin cancer, which includes basal cell carcinoma (basal cell carcinoma) and spinocellular carcinoma (spinalioma). Black skin cancer (malignant melanoma) is rarer but often more malignant.

Skin cancer can be dangerous if it metastasizes or grows into important organs. This applies to all types: If detected and treated early, the chances of curing skin cancer are good.

More on the clinical picture of skin cancer

How skin cancer develops

Skin cancer can occur anywhere on the body. White skin cancer in particular often occurs on sun-exposed areas of the face such as the bridge of the nose, forehead, ears, lower lip, or on the neck, forearms, back of the feet and hands.

It’s not just too much sun on the skin that can cause skin cancer. Chronic exposure to daylight (hours spent outdoors) is the main cause of white skin cancer in older people.

Other risk factors for individual or all forms of skin cancer include

  • Frequent visits to the solarium
  • Many pigment spots / moles (black skin cancer)
  • Light skin type
  • Previous skin cancer or cases of skin cancer in the family
  • Weakened immune system – for example due to diseases such as HIV or drugs such as those administered after an organ transplant (spinocellular carcinoma)
  • Contact with carcinogenic substances such as tar (in cigarette smoke) or arsenic (basal cell carcinoma)
  • Chronic skin inflammation as in the case of “open leg” (spinocellular carcinoma)
  • Rare hereditary diseases such as xeroderma pigmentosum or basal cell nevus syndrome

How do I recognize skin cancer?

The ABCD rule can be used to recognize black skin cancer:

  • Asymmetry: Skin cancer is usually irregular in shape.
  • Boundary: Skin cancer is irregularly bounded, i.e. has a fringed, blurred or jagged edge.
  • Color: When a healthy pigment spot develops into skin cancer, the color usually changes. A dark, uneven (blotchy) coloration is then typical. Sometimes skin cancer is also unusually colored, for example bluish, white or skin-colored.
  • Dynamics: A healthy pigment spot remains more or less the same, while skin cancer changes in size, color, shape or thickness. The changes usually take place slowly.

Caution: Not all of these characteristics are always present in skin cancer! With regard to white skin cancer, crusts or wounds that do not heal within 4 weeks are suspicious.

Detecting and treating skin cancer early

How do I prevent skin cancer?

Acute sun exposure and the resulting sunburn can cause lasting damage to the skin and promote skin cancer. Chronic exposure to daylight, even in cloudy weather or in the shade, is also responsible for white skin cancer in old age. If you observe the following rules, your skin can be well protected from too much sun and from skin cancer:

  • Don’t lie in the sun to get a tan. Avoid lunchtime from 11 am to 3 pm. UV radiation is at its strongest during this time. Wear tight clothing, a hat and sunglasses and protect uncovered parts of the body with sun cream.
  • Only use sun creams with a high or very high sun protection factor (SPF 30 – 50). It is also important that the sunscreen protects well in the UVA range.
  • Also protect the skin when it is cloudy or when you are in the shade. UV rays do not stop at clouds. Around 50 percent of the rays also reach the skin there due to the light reflections.
  • The highest level of caution applies to children’s skin. It still has almost no natural sun protection and is extremely sensitive. Children under the age of two should not be exposed to the sun at all. Later only with a high sun protection factor, sunglasses and a hat.

How skin cancer is treated

After a thorough examination, there are various treatment methods for skin cancer: surgical removal, systemic therapy (medication) or photodynamic therapies. Which therapy is used depends on the type of skin cancer.

Combined treatments are often used. After treatment, regular follow-up checks are carried out by the dermatologist in order to detect any recurrence of cancer at an early stage

More information on skin cancer therapy

Interdisciplinary treatment

The USZ has a specialized team for each of the different types of skin cancer. A specialty of dermatology at the USZ is the removal of white skin cancer using so-called Mohs surgery: the tumor is cut out at a relatively close distance, after which the piece of tissue at the edges of the cut is immediately examined under a microscope. If tumor remnants are found, additional tissue is removed at this site. These steps are repeated until no more tumor remnants are found.

This procedure has two decisive advantages: Firstly, there are far fewer relapses: instead of around five to 25 percent of patients (depending on the type of tumor), only one to five percent have to be operated on again later due to a relapse. Secondly, the aesthetic result is better, as only as much tissue is removed as necessary.

If the white skin cancer is already so large that it can no longer be treated surgically or has already formed metastases (offshoots), medication or radiotherapy (or combinations) may also be necessary. Targeted therapy using smoothened inhibitors (tablets) is available for basal cell carcinoma, while immunotherapy with anti PD1 is now also approved for spinocellular carcinoma.

Responsible department

Department of Dermatology
University Hospital Zurich
Rämistrasse 100
8091 Zurich

To the department