Skin cancer occurs when errors (mutations) in the DNA of skin cells lead them to grow out of control. It can spread to other parts of the body and cause serious, sometimes life-threatening health problems.
Skin cancer is almost always curable when it’s found and treated early. Check your body for new growths or changes in old spots at least once a month.
Basal cell carcinoma
Basal cell carcinoma (BCC) is the most common type of non-melanoma skin cancer. It occurs when basal cells develop mutations, most often due to chronic sun exposure. BCCs typically grow slowly and are nearly always curable when detected early. They almost never spread to other parts of the body, although they can be disfiguring and cause scars if left untreated.
BCCs usually appear as a pink or flesh-colored bump, papule or nodule. They can resemble an open sore or a scab and may have spiky edges. They may ooze clear fluid or bleed when touched. Some BCCs are darker in color, referred to as pigmented nodules or sclerosing basal cell carcinoma.
It is important to have any changes in the skin examined by a doctor or dermatologist. GPs can examine the lesions and refer you to a specialist for a biopsy if they are unsure or suspect skin cancer. A biopsy involves injecting local anaesthetic into the area, scraping off a small part of the lesion with a sharp tool and then using electric current to burn the edges of the tumour.
Despite being the most common non-melanoma skin cancer, BCCs can be difficult to treat effectively. If the tumour is large, or if it grows near important structures like the eyes, nose or ears, radiation therapy with generous margins is an option.
Squamous cell carcinoma
Squamous cell carcinoma develops when flat, thin squamous cells in the middle and outer layers of skin get unusual changes (mutations). These mutations cause the cells to grow out of control and not die at their normal time. They may also spread to other parts of the body.
These cancers usually appear as red, scaly patches or ulcers that don’t heal. They often grow and thicken over several weeks or months. They usually occur on sun-damaged skin or on preexisting growths, such as warts or actinic keratoses, but they can also arise spontaneously on what appears to be healthy skin. People with an inherited, highly UV-sensitive condition called xeroderma pigmentosum have a higher risk of these cancers.
If a squamous cell carcinoma isn’t treated, it can destroy nearby tissue and spread to other parts of the body, such as lymph nodes or internal organs. Untreated squamous cell carcinoma can be fatal, especially when it occurs on the lips, scalp, ears or nose.
Squamous cell carcinomas can be diagnosed with a skin biopsy or by performing a simple test on a sample of your blood. We can also use drugs that target and kill cancer cells or that prevent them from growing, such as 5-fluorouracil (5-FU) and imiquimod. These medications are applied directly to the tumor. They can be used alone or in combination with surgery and radiation therapy.
Melanoma
Melanoma is the most dangerous form of skin cancer and can spread to other parts of the body. It starts in the cells that give skin its colour (melanocytes) and usually develops in a mole. But it can also appear as a new spot or on areas of skin that do not have any existing moles.
It is important to check all of your skin regularly and especially sun-exposed areas for any changes in the shape, size or colour of any spots or moles. Any changes should be checked by your doctor as they may indicate that a melanoma has developed.
If a melanoma is diagnosed, further tests are needed to find out if it has spread and what stage it is at. These may include a sentinel lymph node biopsy and CT, MRI or PET scans.
Melanomas can affect people of all races and ages. However, it is more common in people with fair skin that freckles easily or does not tan, and in those who have many moles or those that are larger than average. People with a family history of melanoma are at higher risk. There is no organised screening program for melanoma but people are advised to see their GP or dermatologist if they notice any unusual-looking skin lesions. It is particularly important for young people and those with a history of previous melanoma to be vigilant and visit their doctor regularly.
Treatment
Skin cancer is cured when it is detected and treated early. If it is left untreated, it may spread to other parts of the body. Nonmelanoma skin cancers (basal cell and squamous cell) and melanoma can be fatal.
Your treatment will depend on the type, size and location of the tumor as well as your age and general health. The treatment options include surgical removal, medication and radiation therapy. Your medical team will discuss these treatments with you and consider how they may affect your appearance and how your body works.
Surgery is the most common treatment for skin cancer. Your doctor will remove the tumor and a small area of healthy skin around it. The edges are then checked under a microscope to make sure all the cancer cells have been removed. Your dermatologist may use a technique called Mohs surgery, which is a special surgical procedure that saves as much healthy tissue as possible.
Medications may be used to destroy cancer cells or to stop them from growing. These drugs are given through your bloodstream and can reach cancer cells throughout the body. They can be taken as pills or applied topically to the cancer site.
If you have had skin cancer, it is important to get regular checkups. A small percentage of skin cancers can come back after treatment, so it is important to catch them in their early stages. You can help reduce your risk of skin cancer by avoiding exposure to the sun and wearing protective clothing, especially when it’s hot outside.