What is Skin Cancer?
Skin cancer is an abnormal growth of cells on top layers of the skin, most often attributed to sun exposure.
An uncontrolled growth of skin cells happens when the DNA of the cells is altered by UV light. It triggers genetic defects or mutations causing the cells to multiply at a rapid pace and form malignant tumors. (1)
In 2015 over 80,000 new cases of skin cancer were reported in the US, of which almost 9,000 were fatal. Skin cancer is one of the most prevalent types of cancer, and is more common as people age. It can affect all ethnicities but is more prevalent in people with paler skin. (2, 3)
Skin cancer usually develops on areas of skin exposed to the sun or another source of UV light, such as tanning beds. Exposed areas generally include the face, lips, ears, neck or scalp. It also appears on the chest, back or legs.
Though not as prevalent, skin cancer also appears on areas of the body not exposed to sunlight.
The most common type of cancer is non melanoma, a slow developing cancer that generally does not spread to other body parts. There is a second less common type, melanoma, which often can spread and is more serious.
With both non melanoma and melanoma, there are different types with signs and symptoms that can vary. We will look at the most common types of each.
Non Melanoma Skin Cancer
The initial signs of this cancer appear as lumps or small areas of discolored skin that do not go away. The lumps usually feel firm and are red in color; they can sometimes become ulcerated. Discolored patches of skin might be scaly and flat. (4)
Basal Cell Carcinoma
This cancer originates in the lower part of the skin’s top layer (epidermis). It looks like a small flesh colored or white lump which can sometimes bleed. It might also appear pearly and smooth, or resemble a scar looking flat, yellow, white or waxy.
Generally located on areas of the body exposed to sunlight, these rarely spread elsewhere in the body. Progression of this cancer is usually slow. (5)
Squamous Cell Carcinoma
Squamous cells are flat, thin cells which look similar to fish scales and are found on the skin’s surface.
This cancer looks like scaly red patches, warts, open sores or lumps raised from the skin with a dent in the centre. This type of skin cancer might bleed or crust over.
It most often appears on places like the face, ears, lips and hands, or other body parts exposed to the sun. While rare, it can also appear on the genitals. (6)
This precancerous form of squamous cell carcinoma develops slowly. Sometimes it’s called squamous cell carcinoma in situ.
It presents as a red, scaly, and occasionally itchy patch on the skin.
While not actually classed as a skin cancer it has the potential to develop into squamous cell carcinoma if left untreated. (7)
Also called solar keratoses, these scaly dry patches of skin result from long term damage caused by sun exposure.
They appear red, brown or pink in color and vary in size from a few millimeters to a few centimeters.
The skin where these patches are located can appear thickened and may look like small spikes or horns.
Again, classed as a pre cancer, left untreated this condition has the ability to develop into squamous cell carcinoma. (8)
Melanoma is the most serious type of skin cancer which has the potential to spread to other areas of the body. It forms in cells called melanocytes which are responsible for producing melanin, the pigment which colors skin.
These cells are located in the lower layers of the skin. When exposed to light, whether from the sun or artificial sources, they make more pigment which darkens the skin.
These malignant cells can appear in a few forms. They can be moles, dark spots or small sores.
There are things to look out for are called the A,B,C,D,Es of melanoma.
A represents asymmetry. Moles, when healthy, are usually round and symmetrical; an irregular shape is a sign to look out for.
B represents border. Healthy moles usually have defined borders, and edges that appear ragged or irregular could indicate melanoma.
C represents color. Moles are usually even in color. Changes to more than one color are a sign for concern.
D represents diameter. Melanomas tend to be larger in size, more than the size of a pea, or larger than a quarter inch.
E represents evolving. Changes in the color, shape or size of a mole or spot over a period of time are further symptoms. They could also bleed, itch or form a crust. (9)
There are stages of both types of cancer.
Called melanoma in situ, abnormal melanocytes are seen in the epidermis which could become cancerous.
This is further divided into two stages.
Stage IA sees the tumor measuring no more than a millimeter thick and it’s not ulcerated.
Stage IB again describes a tumor no more than a millimeter thick but it’s ulcerated, or one that is between one and two millimeters and not ulcerated.
This is also divided into three stages.
Stage IIA represents a tumor which is either between one and two millimeters thick and ulcerated, or between two and four millimeters and not ulcerated.
Stage IIB sees the tumor either between two and four millimeters and ulcerated or over four millimeters and no ulceration.
Stage IIC indicates a tumor more than four millimeters thick and ulcerated.
By this stage the tumor might be any thickness, and ulceration might be present or not. The cancer might have spread to the lymph nodes or the lymph nodes have joined together.
It is also possible for cancer to be found in lymph vessels between the tumor and lymph node. Cancer can also be located more than two centimeters from the original tumor.
There might be small tumors also located no more than two millimeters from the original tumor, on or underneath the skin.
This final stage finds the cancer has spread elsewhere in the body such as the liver, lungs, kidneys, bones, brain, gastrointestinal tract or soft tissues. It might also be found in skin in areas away from the place of origin. (10)
Non Melanoma Stages
Abnormal cells are located in either the squamous cells or basal cells which could become cancerous. This is also called carcinoma in situ.
At this stage cancer has formed but is not larger than two centimeters at its widest point. It might also have one high risk features.
High risk features include a tumor which is thicker than two centimeters. It also refers to a tumor that has spread into lower layers of the skin or the fat layer beneath the skin.
This stage also involves other tumors. These include ones that have spread to nerve pathways, originate on an ear or a lip with a hair, or differ in appearance from normal cells under a microscope.
The tumor at this stage is either larger than two centimeters at the widest point or any size with two or more high risk features.
This represents a spread of cancer to the eye socket, jaw or side of the skull. It might also have migrated to the lymph node on the same side of the body, enlarging it up to three centimeters.
Alternately, cancer has migrated to a lymph node on the same side of the body and the node is not larger than three centimeters. Or, the tumor is no larger than two centimeters and has one high risk feature.
If a tumor is larger than two centimeters, or is any size and has two or more high risk features, it is also included in this stage
This final stage can be one of four things.
Firstly, the tumor might be any size and cancer has spread to the eye socket, jaw or side of the skull. It will also be found in a lymph node on the same side and that node will be between three and six centimeters. It could also have spread to multiple lymph nodes on either side of the body, and the nodes are not larger than six centimeters.
Secondly, the tumor could be any size and have migrated to the eye socket, jaw, spine, skull or ribs. It will also be found in one lymph node no larger than six centimeters.
Thirdly, the tumor might be any size and have spread to the spine, base of the skull or the ribs, and be in the lymph nodes.
Finally, the cancer has spread elsewhere in the body.
These stages apply to non melanomas that are found anywhere apart from the eyelid. Cancers found there have a different set of stages. (11)
The main treatment for skin cancer is surgery. The type of surgery used is dependent on the type of cancer and its location.
Surgery will remove the cancer and some of the surrounding skin. When cosmetic factors come into consideration there are procedures that aim to minimize the aesthetic impact.
Non surgical options include freezing the skin cancer (cryotherapy), light therapy (photodynamic therapy) and radiotherapy. When the cancer is advanced or has spread then medications and chemotherapy can be administered.
When treated early enough, the outcome for skin cancer is good, particularly in the case of non melanoma. (12, 13)
What is skin cancer? Skin cancer is an abnormal growth of cells on the skin, most often attributed to sun exposure.
What are the signs of skin cancer? Skin cancer is seen as changes on the skin’s surface, including scaly red patches or lumps. Moles might change in appearance. There is the propensity for any of these marks to itch or bleed.
How do you develop skin cancer? Most skin cancers are caused by overexposure to UV light without appropriate protection for the skin.
How are you diagnosed for skin cancer? A doctor will usually be able to recognise a potential skin cancer. They may refer you for further tests or to see a skin specialist.
What is the best treatment for skin cancer? Surgery is the main treatment for skin cancer.
What are the long term complications of skin cancer? While most skin cancers can be treated successfully, if untreated the cancer can spread elsewhere in the body.
Is skin cancer considered a disability? Skin cancer is considered a disability but there are caveats. The cancer must have spread, be a melanoma which has recurred, or affecting other parts of the body.
Is there a cure for skin cancer? Most skin cancers, when caught early enough, can be cured.
Is skin cancer life threatening? When a skin cancer spreads through the body it can be life threatening.
Skin cancer is a multiplication of abnormal cells on or under the skin’s surface. It is generally caused by overexposure to UV light.
Fortunately, when recognised early enough, most skin cancers can be treated successfully.