Causes of Skin Cancer - Basal Cell Carcinoma, Melanoma or Squamous Cell Carcinoma, do you know the r
Posted Jan 26 2009 4:32pm
The incidence of skin cancer has increased greatly in recent years, due in part to greater exposure to UV radiation from the sun. In 1990, 600,000 Americans were diagnosed with either basal cell or squamous cell cancers. This is up from 400,000 in 1980, a staggering 50% increase.
Australia has the highest rate of skin cancer in the world accounting for 6 per cent of all the lethal forms of skin cancer diagnosed globally. About 1200 people die each year in Australia as a result of skin cancer. It is expected that this number will increase.
What are the causes of skin cancer?
Over exposure to the sun is the primary cause of skin cancer, although there are other factors including heredity and environment, sunburn and UV light damage the skin, and this damage can lead to skin cancer.
Because having a 'healthy' tan is considered a 'good look', most young people tend to spend extensive periods of time in the sun. It is estimated that most people receive 50 percent of their lifetime exposure to the sun by 18 years of age ( UMM ).
What does tanning do to the skin?
Sunlight or rather the sun's UV radiation has a profound effect on the skin and causes more than just your skin to go brown. Premature skin aging, skin cancer, and a range of other skin changes are a direct result of over exposure to the sun and in particular UVA and UVB radiation. By far the worst effect however, is the potential for developing skin cancer.
What are risk factors for skin cancer?
There are a number of predisposing risk factors that need to be considered:
1. Heredity - a family history of skin cancer should ring alarm bells and serve as an indication that over exposure to the sun, by an individual who has a family history of skin cancer, stands an increased risk of developing this disease. This is particularly so for people with fair skin and a Anglo-Saxon background.
2. Environment/Climatic - the reduction of ozone in the earth's stratosphere, especially over Australia, allows for higher levels of UV light to reach the earth's surface. Increased UV radiation has lead to an increased incidence of skin cancer in the past few decades.
Types of Skin Cancer Caused by the Sun The 3 main skin cancers are:
basal cell carcinoma, and
squamous cell carcinoma.
Melanoma is the most deadly skin cancer because it spreads to other areas of the body more readily than the other skin cancers. It is believed that the amount of exposure of the skin to the sun before the age of 20 is actually the determining risk factor for melanoma.
Basal cell carcinoma is the most common skin cancer and tends to only spread locally.
Squamous cell carcinoma is the second most common skin cancer, and it can spread to other parts of the body, although not as commonly as melanoma. The risk of getting basal cell carcinoma or squamous cell carcinoma is determined by a person's lifetime exposure to UV radiation and the person's pigment protection.
What is melanoma?
Melanoma is a cancer that originates in the pigment-producing cells of the skin (melanocytes). Melanocytes are the pigmented cells in the skin that give skin its distinctive colour. Sunlight stimulates melanocytes to produce more melanin (the pigment that darkens the skin) and increases the risk of melanoma. Melanoma usually occurs in adults, but it may occasionally be found in children and adolescents.
Melanoma can begin as a new, small, pigmented skin growth on normal skin, most often on sun-exposed areas, or it may develop from pre-existing pigmented moles. As mentioned earlier, melanoma can runs in families. Unlike Basal Cell Carcinoma, Melanoma readily spreads to distant parts of the body, where it continues to grow and destroy tissue.
Melanomas can vary in appearance. Some are flat, irregular brown patches containing small black spots. Others are raised brown patches with red, white, black, or blue spots. Sometimes melanoma appears as a firm black or gray lump ( Merck & UMM)
Melanoma is the most serious type of cancer of the three types discussed here. While it occurs less often than the other two types, it has the highest mortality rate and is responsible for 75% of all deaths from skin cancer ( UMM ).
What are the risk factors for melanoma?
People with the following characteristics may be at an increased risk for melanoma:
blond or red hair
family history of melanoma
a changed or changing mole
many ordinary moles (more than 50)
an immunosuppressive disorder
dysplastic nevi (Atypical moles)
The amount of time spent unprotected in the sun directly affects your risk of skin cancer.
nability to tan
However, having dark-brown or black skin is no guarantee against melanoma. African-Americans can develop this type of skin cancer, especially on the palms of the hands, soles of the feet, under nails, or in the mouth and they can and do get sunburn.
What are the symptoms of melanoma?
The following are the most common symptoms of melanoma. However, each individual may experience symptoms differently. Symptoms may include:
change in the size, shape, or colour of a mole
oozing or bleeding from a mole
mole that feels itchy, hard, lumpy, swollen, or tender to the touch
Because most malignant melanoma cells still produce melanin, melanoma tumours are often shaded brown or black. Melanoma can also appear on the body as a new mole. Men most often develop melanoma on the area of the body between the shoulders and hips, or on the head or neck. Women most often develop melanoma on the arms and legs. However, melanoma can spread quickly to other parts of the body through the lymph system, or through the blood. Like most cancers, melanoma is best treated when it is diagnosed early (UMM).
The symptoms of melanoma may resemble other conditions or medical problems. Always consult your physician for a diagnosis. It is also recommended that at least twice a year you consult a dermatologist to have your skin examined closely for any kind of unusual changes.
Basal cells are found in the lowest layer of the epidermis. Although basal cell carcinoma may not originate in the basal cells, the disease is so named because the cancer cells resemble basal cells.
Basal cell carcinoma usually develops on skin surfaces that are exposed to sunlight, commonly on the head or neck, back of the hands or the forearms. The tumours usually begin as small, shiny, firm raised growths (papules) that enlarge very slowly, sometimes so slowly that they go unnoticed as new growths. However, the growth rate varies greatly from tumour to tumour, with some growing as much as 1-2cm in a year ( Merck ).
Basal cell carcinoma accounts for more than 90 percent of all skin cancers in the United States. It is often easily detected and has an excellent record for successful treatment. According to the American Academy of Dermatology, the cure rate for basal cell carcinoma is 95 percent, when properly treated. Although this type of cancer rarely spreads to other parts of the body, it can extend below the skin to the bone and cause considerable local damage. And, non-melanoma skin cancer places people at high risk for developing additional skin cancers.
Who is at risk for basal cell carcinoma?
Basal cell carcinoma is the most common skin cancer found in Caucasians. It seldom occurs in dark-skinned persons. People who have this cancer frequently have light hair, eyes, and complexions, and they do not tan easily.
How does basal cell carcinoma develop?
This highly treatable cancer starts in the basal cell layer of the epidermis (the top layer of skin) and grows very slowly. A basal cell carcinoma usually appears as a small, shiny bump or nodule on the skin, and mainly on the areas exposed to the sun, such as the head, neck, arms, hands, and face.
Squamous Cell Carcinoma
Squamous cell carcinoma is cancer that originates in the squamous cells (keratinocytes).
Squamous cells (keratinocytes) are the main structural cells of the epidermis. Squamous cell carcinoma usually develops on sun-exposed areas but may grow anywhere on the skin or in the mouth, where sun exposure is minimal. It may develop on normal skin but is more likely to develop in precancerous skin growths caused by previous sun exposure.
Squamous cell carcinoma is characterized by its thick, scaly, irregular appearance. Fair-skinned people are much more susceptible to squamous cell carcinoma than darker-skinned people. This type of cancer is also more likely to develop in chronic sores-such as chronic skin ulcers-or in skin that has been scarred, particularly by burns.
Squamous cell carcinoma begins as a red area with a scaly, crusted surface that does not heal. As it grows, the tumor may become somewhat raised and firm, sometimes with a wartlike surface (see Mouth Growths: Types of Oral Cancer). Eventually, the cancer becomes an open sore and grows into the underlying tissue ( Merck ).
Most squamous cell carcinomas affect only the area around them, penetrating into nearby tissues. But some spread (metastasize) to distant parts of the body and can be fatal. Those that occur near the ears and lower lip are more likely to spread. Squamous cell carcinoma in the mouth often spreads ( Merck ).
Danny Siegenthaler is a doctor of traditional Chinese medicine and together with his wife Susan, a medical herbalist and Aromatherapist, they have created Natural Skin Care Products by Wildcrafted Herbal Products to share their 40 years of combined expertise with you.