Skin cancer: symptoms, causes and treatment

Your skin consists of three main layers. The top layer is the epidermis, where the vast majority of skin cancers originate. There are different types of cells within the epidermis: basal cells form the bottom row and produce new skin cells, squamous cells lie above and form the protective outer layer.

Basocellular carcinoma originates from basal cells and is by far the most common form of skin cancer among light-skinned people. This form grows slowly and remains local. The good news is that basocellular carcinoma almost never spreads to other parts of the body, making it the least malignant form of skin cancer. People usually get this for the first time around the age of 65.

Squamous cell carcinoma develops from squamous cells and is the second most common skin cancer. This form is slightly more aggressive and can spread to nearby lymph nodes, but the chance remains low. Fortunately, this rarely happens if the cancer is detected and treated early. On average, squamous cell carcinoma shows up for the first time around the age of 74.

The development of these skin cancers is a gradual process that often takes years. It starts with damage to the DNA in skin cells, mainly caused by ultraviolet (UV) radiation from the sun or tanning beds. Every time UV radiation hits your skin, it can cause minor damage to the genetic material. Repeated exposure overloads your skin's repair mechanisms. Some damaged cells begin to behave abnormally and divide uncontrollably. Initially, precancerous lesions such as actinic keratosis often develop, a rough scaly patch from which skin cancer can later develop.

In basocellular carcinoma, intensive exposure to UV radiation mainly plays a role. Think of beach vacations or intensive sunbathing. That sunscreen you got as a child has more impact than you think. The damage stays in your skin for decades. Squamous cell carcinoma is more likely to occur due to prolonged, cumulative exposure. It's not about the one time you sunburn, but about the total amount of UV radiation that your skin has absorbed over the years. People who have worked outside all their lives are therefore at increased risk.

Your skin type largely determines how sensitive you are. People with a light skin type, who burn quickly and have difficulty tanning, are most at risk. Their skin has less melanin, the pigment that protects against UV rays. A family history of skin cancer also increases your risk, because genetic factors play a role in how well your skin can process UV damage. Medicines that suppress your immune system also increase the risk. This is because your immune system plays a role in cleaning out abnormal cells before they can grow into cancer. When this system is suppressed, abnormal cells are more likely to continue to grow.

Both forms of skin cancer can look very different and sometimes initially look like harmless skin disorders. That's why it's important to keep a close eye on changes in your skin.

Basocellular carcinoma starts as a smooth, glassy ball that grows very slowly. The colour may vary: brown, pink, skin-coloured or dark red. A remarkable feature is that the ball is often slightly covered with fine blood vessels that can be seen as thin red lines. Over time, a small sore with a scab appears in the center. This sore does not heal, even though the scab may occasionally fall off and come back. Around this central sore, you can see a ring with a characteristic pearly shine. This shiny border is often the most prominent feature. Sometimes a superficial basocellular carcinoma looks different and looks more like a scaly eczema patch. This variant grows flatter over the skin but has the same underlying problems.

Squamous cell carcinoma starts as a pink-red lump that rises above the skin. It often has a scaly crust on it that comes back every time you remove it. In contrast to basocellular carcinoma, it does not have fine blood vessels and does not have a pearl shine. It often feels a bit harder and grows faster. On the lips, squamous cell carcinoma looks different. You notice a white spot that slowly thickens and is covered with tiny flakes. This shape can be very subtle at the start and is sometimes confused with dry lips.

The following applies to both forms: if a spot, bump or wound does not heal within four to six weeks, or if it gradually grows larger, it is wise to have it checked. Bleeding when touched lightly is also a warning sign.

Basocellular carcinoma mainly occurs in the face. The nose is a favorite location, probably because it's the most prominent part of your face and therefore captures the most sun. The cheeks, forehead, temples and the area around the eyes are also often affected. The ears, especially the top and back, are sensitive areas where people often forget to apply sun protection. Outside the face, it can also occur on the shoulders, upper back, and chest. The scalp is a risk zone for balding people.

Squamous cell carcinoma follows a similar pattern. The face is also important here, especially the forehead, cheeks and nose. The lips are a specific risk zone, especially the lower lip that catches more sun. The neck, especially the back, and the ears are highly sensitive. The backs of the hands are a common location due to constant exposure during outdoor activities. The forearms are also regularly affected, especially in people who drive a lot with the window open. A striking difference is that squamous cell carcinoma can also occur in areas of chronic irritation. Old burns or scars can sometimes be where cancer develops decades later.

Fortunately, the treatment of these skin cancers is often successful, especially if they are detected early. For basocellular carcinoma, surgical removal is the standard treatment. During the procedure, you will receive local anaesthesia. The doctor excises the tumour with a few millimetres of healthy skin around it as a safety margin. The wound is closed with stitches. The removed tissue goes to the laboratory where it is checked that the edges are free of cancer cells. In the case of larger lesions or tumors in difficult areas such as an eyelid or nose, a plastic surgeon takes over the treatment. These specialists sometimes use special reconstruction techniques to close the wound.

Alternative treatments are possible for certain basocellular carcinomas. Photodynamic therapy is a technique that first applies a special cream to the tumor that makes the cancer cells sensitive to light. After a few hours, specific light is focused on the area, which destroys the cancer cells. This treatment often leaves a better cosmetic result. Electrocoagulation is a method in which the doctor burns away the tumor with electric current. Cryotherapy involves freezing the tumor with liquid nitrogen. Both methods are particularly suitable for small tumors. Some basocellular carcinomas can be treated with creams that directly kill cells or stimulate your own immune system. You apply these creams daily to the affected area for a few weeks. The advantage is that no scar remains, but this treatment is not suitable for all types.

Squamous cell carcinoma often requires a slightly more aggressive approach because of the risk of metastasis. Surgical removal is the standard treatment. The doctor removes the tumor with a wider margin of at least 5 millimeters of healthy skin around it. For superficial squamous carcinomas at a very early stage, photodynamic therapy and cryotherapy can provide good results with fewer scars.

In skin cancer, it's crucial to understand that some approaches don't work and can even be dangerous by wasting valuable treatment time. Sun cream as a treatment is a common misunderstanding. Sun cream is excellent for prevention, but once skin cancer has developed, it does not stop growth. The damage in the cells is already present. Sunscreen does help prevent new skin cancer in other areas.

Natural remedies and alternative treatments have not been scientifically proven effective against skin cancer. Products such as tea tree oil, turmeric paste or apple vinegar have no effect against cancer cells. They can even be harmful by causing irritation or delaying diagnosis. Simply scratching or trying to remove the tumour yourself is dangerous. You only remove the surface while the cancer cells stay deeper in the skin. You're causing bleeding and possibly infections, but you're not solving the problem.

Waiting is also not an option. Although skin cancer often grows slowly, it always grows if it is not treated. A small tumor that is now easily removed can grow into a large tumor that requires extensive surgery. Vitamin supplements as a treatment are also ineffective. There is no evidence that high doses of vitamin C, vitamin D, or other supplements kill cancer cells. Over-the-counter creams for skin problems don't work against skin cancer and can mask symptoms.

Is skin cancer fatal?

Basocellular carcinoma is almost never fatal because it does not spread. Squamous cell carcinoma is slightly more serious because it can metastasize, but if detected and treated early, the chance of survival is excellent. More than 95% of people with squamous cell carcinoma are still alive after 5 years.

How soon do I need to see a doctor?

If you have discovered a suspicious stain, it is wise to make an appointment within a few weeks. It's not an acute emergency, but don't delay it for months either. Although skin cancer grows slowly, every month of delay does mean that the tumor is getting bigger.

Do scars remain after treatment?

Yes, after surgical removal, a scar remains. The size depends on how big the tumor was and how much tissue had to be removed. The scar is red and conspicuous at first, but usually fades within a year. In photodynamic therapy or cryotherapy, the scars are minimal.

Can skin cancer come back after treatment?

In the same spot, skin cancer rarely recurs after complete removal, in less than 5% of cases. However, you can develop new skin cancer in other places. That's why regular monitoring of your entire skin is important. Teaching self-inspection is extremely important.

Do I have to be careful with the sun all my life?

Yes, after skin cancer, your risk of new tumors remains increased. Wear protective clothing, use sunscreen with at least a factor of 30 every day, and especially stay out of the sun between 11 a.m. and 3 p.m., when the radiation is strongest. This is a lifelong change in your lifestyle.

Are preventative treatments possible?

For people with multiple solar keratoses or a very high risk of skin cancer, there are preventive creams that can treat precancerous lesions. Photodynamic therapy of larger areas of skin can also be considered. Regular skin checks are the most important preventative measure.

1. Skindr dermatologists
2. Health and Science: Malignant Epidermal Skin Tumors ‍
3. eBPNet (Evidence-Based Practice Network)
4. NHG standard Suspected skin disorders
5. Foundation Against Cancer: Skin Cancer Non-Melanomas