Causes of Skin Cancers
The most common cause of skin cancers are ultraviolet (UV) rays, either from the sun, or from UV-emitting lamps, like those in tanning saloons. Both UV-A and UV-B rays may cause skin cancer.
Other possible causes of skin cancers include:
- A high dose or repeated X-ray exposure (1,2)
- Exposure to arsenic (pesticides, wood preservatives, miners, sheep shearers, farmers) (1), pitch (from distillation of wood or coal tar), creosote, or radium (5)
- Therapy that destroys immune cells – chemotherapy, radiotherapy, immunosuppression in organ or bone marrow transplantation (2)
- Smoking – increases risk of squamous cell carcinoma (4)
Risk Factors for Developing a Skin Cancer
The possibility of developing a skin cancer increases with the following factors:
- People with fair skin, freckles, blond or red hair, blue or green eyes are at most risk to develop skin cancer (2).
- Skin disorders with lack of skin pigment melanin (albinism, xeroderma pigmentosum) (2)
- Tanning poorly (1)
- Several, unusual or big moles at birth (2)
- New or changing mole (5)
- Close relatives with skin cancer (2)
- Previous skin cancer (2)
- Severe sunburn, especially early in life (2)
- Scars (2)
- Actinic keratosis (1)
- HIV infection – increases risk of Kaposis’s sarkoma (3)
- A constant exposure to the UV rays: a high altitude, regions close to equator and regions with impaired ozone layer in atmosphere (Australia) (1)
- Repeated sun exposure (outdoor workers, sailors, farmers, drivers) (1)
- White race, men, age after 50 (6)
Preventing Skin Cancer
Skin cancer prevention includes avoiding the sun and other causes of skin cancer, protection against these causes, regular self-examination, and checking suspicious skin changes by a dermatologist.
Avoiding Causes of Skin Cancer
- Avoid direct sun exposure between 10 a.m. and 4 p.m., especially in summer, in regions close to equator (± 30 degrees latitude), and in high altitudes.
- Not only long term exposure, but also short non-regular exposures (minutes) to intense sunlight may increase the risk of a skin cancer. A person with fair skin may get burns in 15 minutes, so avoid getting burns.
Avoiding Tanning Saloons
- UV-A rays from lamps in tanning saloons, once considered as non-harmful, are now recognised as the possible cause of a skin cancer.
- There is no proof that tanning prevents skin cancer.
Avoiding Other Causes of Skin Cancer
- Repeated X-ray or CT investigations, radiotherapy, chemotherapy may increase risk of skin cancer
- Oil and coal by-products (pitch, soot), mostly from air pollution should be avoided
- Arsenic and other substances in pesticides, wood preservatives are cancerogenous.
- Smoking also causes skin cancer
Protection Against Causes of Skin Cancer
- When choosing a shadow, bear in mind that sunlight can reflect from water or snow, sand, concrete, or any other white or light colored surface.
- Wear long-sleeved cotton shirts, long pants, broad hat (to protect face, neck, scalp and ears), and UV-protecting glasses (skin cancer COMMONLY appears around the eyes) when you are exposed to intense sun.
- Apply sunscreen with sun protective factor (SPF) at least 15, 30 minutes before sun exposure, and re-apply it every 2 hours and after swimming or sweating. On the beach, in mountains, during skiing and in areas around equator, use sunscreen even when you are in the shadow or in cloudy or cold weather, since sunlight easily reflects from nearby bright surfaces, sand water, and snow, or breaks through the clouds. No sunscreen can completely prevent your skin from harming effect of the sun though.
- Wear protective clothes when dealing with pesticides, lacquers…
- Do not smoke.
- Keep newborns out from the direct sun.
Skin Self-Examination and Checking by Dermatologist
Skin cancers often start to grow insidiously, without pain, and on sites where they are hardly noticed even during changing or washing. So, self-examine your skin once a month:
- You will need bright daylight or a light from a strong lamp, a full-sized mirror and a hand mirror
- Check your body from the head to toes: the scalp, neck, ears and skin around the ears, eyebrows, face – especially eyelids, lips, and all other parts of the body, icluding groin area and nails.
- Every new mole or a mole that has changed in size, color or appearance is suspicious for skin cancer. Check types of skin cancers (pictures included).
- If you are exposed to causes of skin cancers or have risk factors for it, visit a dermatologist once a year to have a thorough skin exam.
Treatment of Skin Cancer
Treatment of skin cancer depends on cancer type, stage, location, patient’s age, and his/her general health state. It is a dermatologist – a specialist for skin diseases – who treats cancer. Methods of skin cancer treatment include:
- Medications and other
In most cases, surgery is the first option to treat cancer. Often only a small ambulatory procedure performed in outpatient ambulance is needed:
- Excision. Small tumors, like small basal carcinoma can be simply excised with the scalpel. Under local anesthesia ( anesthetic is injected in surrounding tissue), a cancer and small amount of healthy tissue around the tumor will be excised to be sure that all cancerous cells are removed. Resulting wound will be sutured, and sutures removed after few days. A small scar will often remain, but this fades to some extent with time.
- Cryosurgery (Greek cryo= cold) is freezing the cancer with applying liquid nitrogen (-196°C) on the cancer. Cryosurgery is mainly used for small surface pre-cancerous growths, like actinic keratoses. The procedure is painless. After the growth falls off, a small pale scar remains.
- Curretage is scraping the lesion with a sharp instrument. The area is then treated with electrodesiccation (Latin desiccare = dry off completely) to kill eventual remaining cancerous cells and to stop bleeding.
- Laser can be used to destroy small superficial cancers.
- Micrographic surgery is a procedure where a cancer is removed layer by layer and each layer is checked under the microscope for presence of cancerous cells, before proceeding. The method is used in large agressive cancers where removing all cancerous cells is essential, but keeping as much as possible of surrounding skin is also important (like on the face).
- A skin graft from the other part of the body may be needed after surgical removal of the skin cancer.
Chemotherapy means treating of cancers with anti-cancer drugs.
- In topical chemotherapy, a cream or lotion with anti-cancer drug is applied on the cancer. It can be used in small superficial cancers. Topical chemotherapy doesn’t cause systemic side effects, but usually results in local inflammation.
- Systemic chemotherapy is mainly used for cancers that have already spread into other organs. Anti-cancer drugs are administered as pills, intra-muscular, or intravenous injections.
In radiotherapy high energy X-ray beam is used to kill cancer cells. It is usually used for cancers on the face that can’t be easily removed with surgery. The procedure is painless. The procedure usually causes temporary local inflammation. Sometimes notable skin changes develop on the treated area.
4. Other Treatments of Skin Cancer
In particular tumors the following therapeutic procedures may be effective:
- In photodynamic therapy (PDT), a medication with tendency to collect in cancerous cells is injected into a vein (1). After 24-72 hours, medication will disappear from normal body cells, but will remain in the cancerous cells. Then a special light is focused on the cancer to activate the medication, and this will destroy cancerous cells. PTD can be used for treat small skin, esophageal, and bronchial tumors (optic tubes with the light are inserted into esophagus or bronchi).
- In cancer immunotherapy, substances that are normally produced by the body to kill harmful cells, may be produced in laboratory and injected into patient’s bloodstream (2). These substances (interferon-A, monoclonal antibodies) collect into tumors and made them susceptible for body’s own immune system.