Skin Cancer Screening
Currently no screening programme exists for skin cancer. There are various different types of skin cancer including:
Melanoma is a cancer that begins in the melanocytes. Other names for this cancer include malignant melanoma and cutaneous melanoma. Most melanoma cells still make melanin, so melanoma tumours are usually brown or black. But some melanomas do not make melanin and can appear pink, tan, or even white. Melanomas can develop anywhere on the skin, but they are more likely to start on the trunk (chest and back) in men and on the legs in women. The neck and face are other common sites.
Having darkly pigmented skin lowers your risk of melanoma at these more common sites, but anyone can get melanoma on the palms of the hands, soles of the feet, or under the nails. Melanomas can also form in other parts of your body, such as the eyes, mouth, genitals, and anal area, but these are much less common than melanoma of the skin.
Melanomas account for about 1% of skin cancer that causes the large majority of skin cancer deaths. Melanoma is more than 20 times more common in whites than in black African or black Caribbeans. Overall, the lifetime risk of getting melanoma is about 2.6%, that is 1 in 38 for whites; 0.1%, 1 in 1000 of blacks; and 0.6%, 1 in 167 for Hispanics.
Melanoma is more common in men overall, but before the age of 50, the rates are higher in women than in men.
The risk of melanoma increases with age. The average age of people when it is diagnosed is 65, but melanoma is not uncommon even amongst those younger than 30. In fact, this is one of the most common cancers in young adults especially in young women.
Risk Factors for Melanoma Formation.
- Ultraviolet Light Exposure
Ultraviolet light exposure is a major risk factor for most melanomas. Sunlight is the main source of UV rays. Tanning beds and sunlight are also sources.
UV light is the main cause of the damaging effects of the sun on the skin. UV rays damage the DNA (genes) inside skin cells. Skin cancers can begin when this damage affects the DNA of genes that control skin cell growth.
The pattern and timing of the UV exposure may play a role in melanoma development. For example, melanoma on the trunk (chest and back) and legs has been linked to frequent sunburns (especially in childhood). This might also have something to do with the fact that these areas aren’t constantly exposed to UV light. Some evidence suggests that melanomas that start in these areas are different from those that start on the face, neck, and arms, where the sun exposure is more constant.
They are also thought to be different from other melanomas on the palms of the hands, soles of the feet, or under the nails. These are known as acral lentiginous melanomas on the internal surfaces such as the mouth and vaginal mucosal membranes where there has been little or no sun exposure.
A mole, also known as a naevus, is a benign pigmented tumour. Babies are not usually born with moles. They often begin to appear in children and young adults. Most moles will never cause any problems, but someone who has many moles is more likely to develop melanoma.
- Atypical Moles and Dysplastic Naevi
These moles look a little like normal moles but also have some features of melanoma. They can appear on skin that is exposed to the sun as well as skin that is usually covered, such as on the buttocks or scalp. Dysplastic naevi often run in families. A small percentage of dysplastic naevi may develop into melanomas. But most dysplastic naevi never become cancer, and many melanomas seem to arise without a pre-existing dysplastic naevus.
- Dysplastic Naevus Syndrome
People with this inherited condition have many dysplastic naevi. If at least one close relative has had melanoma, this condition is referred to as familial atypical multiple mole and melanoma syndrome
People with this condition have a very high lifetime risk of melanoma, so they need to have very thorough, regular skin exams by a dermatologist. Mole mapping can help with this where the skin is photographed regularly.
- Congenital Melanocytic Naevi
Moles present at birth are called congenital melanocytic nevi. The lifetime risk of melanoma developing in congenital melanocytic nevi is estimated to be between 0 and 5%, depending on the size of the naevus. People with very large congenital nevi have a higher risk, while the risk is lower for those with small nevi. For example, the risk for melanoma is very low in congenital nevi smaller than the palm of the hand, while those that cover large portions of back and buttocks have significantly higher risks.
Congenital nevi are sometimes removed by surgery so that they don’t have a chance to become cancer. The chance of any single mole turning into a cancer is very low. However, anyone with lots of irregular or large mole has an increased risk for melanoma.
- Fair skin, freckling and light hair
The risk of melanoma is much higher for whites than for black Africans. Whites with red or blonde hair, blue or green eyes, or fair-skin that freckles or burns easily are at an increased risk.
- Family History of Melanoma
Your risk of melanoma is higher if one or more of your first-degree relatives has had melanoma. Around 10% of all people with melanoma have a family history of the disease. The increased risk might be because of a shared family lifestyle of frequent sun exposure, a family tendency to have fair skin, certain gene changes that run in a family, or a combination of these factors.
- Personal History of Melanoma or Other Skin Cancers
A person who has already had a melanoma has a higher risk of getting a repeat melanoma. People who have had basal or squamous cell skin cancers also have increased risk of getting melanoma.
- Weakened Immune System
A person’s immune system helps fight cancer of the skin and other organs. People with weakened immune systems from certain diseases or medical treatment are more likely to develop many types of skin cancer, including melanoma. For example, people who get organ transplants are usually given medicines that weaken their immune system to help prevent them from rejecting the new organ. This increases the risk of melanoma.
Melanoma is more likely to occur in older patients, but it is also found in younger people. In fact, melanoma is the one of the most common cancers in people younger than 30. Melanoma that runs in families may occur at a younger age.
- Male sex
Men have a higher risk of melanoma than women although this varies by age. Before the age of 50, the risk is higher for women; after age of 50, the risk is higher in men.
- Xeroderma Pigmentosum
Xeroderma pigmentosum is a rare, inherited condition that affects skin cells’ ability to repair damage to their DNA. People with XP have a high risk of developing melanoma and other skin cancers when they are young, especially on sun-exposed areas of their skin.
So what causes melanoma?
- Acquired gene mutations.
These gene changes are usually acquired during a person’s lifetime and are not passed on to children. These acquired mutations seem to happen randomly within a cell without a clear cause. For example, UV light is clearly a major cause of melanoma. UV X-rays can damage the DNA and skin cells Sometimes this damage affects certain genes that control how the cells grow and divide. If these genes no longer work properly, the affected cells may become cancer cells. The most common change in melanoma cells is a mutation in the BRAF oncogene, which is found in about half of all melanomas. Other genes that can be affected in melanomas include the NRAS, CDKN2A and NF1 usually only one of these genes is affected.
Some melanomas occur in parts that are rarely exposed to sunlight. These melanomas often had different gene changes than those in melanomas that develop in sun-exposed areas, such as changes in the C-KIT gene.
- Inherited Gene Mutations
Less often, people inherit gene changes through the family. Familial inherited melanomas most often have changed in tumour suppressor genes such as the CDKN2A or CDK4 prevent them doing their normal job by controlling cell growth. This could eventually lead to cancer.
Can melanoma be prevented?
- Sunlight exposure
Seek shade. Use high factor sun prevention creams.
Avoid tanning beds and sunlight. Protect children from the sun. Screening in the skin regularly may help you spot any new or abnormal moles or other growth. Any mole that becomes painful, change shape, change colour, hurt, itch or bleed should be shown to a medical specialist at the patient’s earliest opportunity.
- Genetic Counselling and Testing for People at Higher Risk of Melanoma.
Gene mutations that increase melanoma risk can be passed down through families, but these account for only a small portion of melanomas. Genetic counselling should be offered.
Basal Cell Carcinomas and Squamous Cell Carcinomas.
Basal cell carcinomas are the most common types of skin cancer. They start in the top layer of skin are often related to sun exposure, about 8/10 skin cancers are basal cell carcinomas. They start in the basal cell layer, which is the lower part of the epidermis.
These cancers usually develop on sun-exposed areas, especially the face, head, and neck. They tend to grow slowly. It’s very rare for a basal cell cancer to spread to other parts of the body. But if it’s left untreated, basal cell cancer can grow into nearby areas and invade the bone or other tissues beneath the skin. If not removed completely, basal cell carcinoma can come back (recur) in the same place on the skin. People who have had basal cell skin cancers are also more likely to get new ones in other places.
Squamous Cell Carcinomas
About 2 out of 10 skin cancers are squamous cell carcinomas and these cancers start in the flat cells in the upper part of the epidermis. These cancers commonly appear on sun exposed areas of the body such as face, ears, neck, lips and backs of the hands They can also develop in scars or chronic skin sores elsewhere. They sometimes start in actinic keratoses (described below). Less often, they form in the skin of the genital area.
Squamous cell carcinomas are usually removed completely, although they are more likely than basal cell carcinomas to grow into deeper lesser skin and spread to other parts of the body.
Precancerous and Other Skin Conditions Related to Squamous Cell Carcinoma.
- Actinic keratosis/solar keratosis (AK)
These are precancerous skin conditions caused by too much exposure to sun. They are usually small, rough or scaly spots that may be pink, red or flesh-coloured. They usually start from the face, ears, backs of the hands and arms of middle aged or older people with fair skin, although they can occur on other sun-exposed areas. People have them usually developed more than one.
They tend to grow slowly and usually do not cause any symptoms (although some might be itchy or sore). They sometimes go away on their own, but they may come back. A small percentage turn into squamous cell carcinomas but most do not become cancer. But it can be hard to tell which ones will, so they are often recommended to be treated. If they are not treated, then you should have regular skin checks.
- Bowen Disease (Squamous Cell Carcinoma In Situ)
This is the earliest form of squamous cell skin cancer. “In situ” means that the cells of these cancers are still only in the epidermis (the upper layer of the skin) and have not invaded into deeper layers when disease appears as a reddish patch.
Compared with AK, Bowen disease patches tend to be larger red, scaly and sometimes crusted. Like AK, Bowen disease usually does not cause symptoms, although it can be itchy or sore. Like most other skin cancers, these patches most often appear in sun-exposed areas. Bowen disease can also occur in the skin of the anus and genital areas. This is often related to sexually transmitted infection with HPV.
Bowen disease can sometimes progress to an invasive squamous cell skin cancer, so doctors usually recommend treating it. People who have these are also at higher risk for other skin cancers, so close follow-up is required.
Keratoacanthomas are dome-shaped tumours that are found on sun-exposed skin. They may start out growing quickly, but their growth usually slows down. Many keratoacanthomas shrink or even go away on their own over time without any treatment. But some continue to grow, and a few may even spread to other parts of the body. They can be hard to tell apart from squamous cell skin cancer, and their growth is often hard to predict, so many skin cancer experts recommend treating them (typically with surgery).
So the mainstay of treatment is regular skin check. No guidelines except for screening, but a regular skin check, self-skin check and a regular dermatology check are essential. All areas should be examined.
Here at The London General Practice, our full health screen includes a complete skin check.
To learn more about the service of The London General Practice please visit our screening home page