Skin cancer is the most common tumor disease of all. There is a difference between white skin cancer (basal cell carcinoma, prickle cell carcinoma) and black skin cancer, known as melanoma, and other rare skin tumors. Next to a genetic disposition, mainly determined by the skin type, the exposure to UV radiation also plays a major role in the development of skin cancer.
White skin cancer
Caused by the cumulative UV exposure—the sum of lifelong light-induced skin damage—, white skin cancer mainly occurs in areas often exposed to light, for example, the face. This is the reason why this tumor mainly occurs in people of 60 years of age or older. The problem about white skin cancer is the so-called field cancerization, which means that multiple skin tumors can occur independently and next to each other, because the light damage has affected the whole area equally. White skin cancer should therefore be treated as soon as possible, as long as large-area measures like immune modulators or photodynamic therapy can take effect. Once invasive tumors have occurred, they have to be excised, which can result in a difficult operation if multiple skin tumors need to be removed. In patients with a healthy immune system, the risk of developing metastases is very low with under 1%. In patients with suppressed immune systems, for example, after an organ transplant, the risk is considerably higher.
Black skin cancer (melanoma)
A much more aggressive form of skin cancer, melanoma can spread into the lymphatic and blood circulation even in the early development. Melanoma can develop from an existing birthmark (nevus), but also from completely normal skin. The intermittently high UV exposure is responsible for the development of malignant melanoma (except for the lentigo maligna melanoma), which can be roughly estimated by the number of sunburns. This is the reason why melanomas often occur in the torso and extremities where they can be found in areas that are rarely exposed to the sun and therefore prone to sunburn, for example during vacations.
However, some melanomas also occur independently of UV exposure, for example on the mucosa inside the nose, in the eyes, or on hands and feet. In case of malignant melanoma, the general principle is: the earlier it is detected, the better the prognosis, because an operation may already result in the cure. If metastasis has already occurred, generally the use of medication will be necessary, with immunotherapies, targeted therapies, or chemotherapies.