Skin Cancer: Causes, Symptoms, Diagnosis and Treatment
Skin cancer is one of the most common types of cancer that begins in the epidermis, an outermost layer of the skin which acts as the body’s major barrier against environmental pathogens and prevent loss of body fluids.
The epidermis is made up of three types of cells: basal cells, squamous cells, and melanocytes. The type of skin cancer depends on which part of the epidermis is affected.
Basal cell carcinoma (BCC)
This is the most common type of skin cancer, accounting for 75%-80% of all cases. BCC usually appears as a small, shiny pink or pearly-white lump with a translucent or waxy appearance. The lump slowly gets bigger and may become crusty, bleed or develop into a painless ulcer.
BCC grows slowly over months or years and rarely spreads to other parts of the body. The earlier a BCC is diagnosed, the easier it is to treat. If left untreated, it can grow deeper into the skin and damage nearby tissue, making treatment more difficult.
Squamous cell carcinoma (SCC)
This type of skin cancer develops in the outer layers of your skin. It appears as a firm pink lump with a rough or crusted surface. The lump often feels tender when touched and may develop into an ulcer.
SCC can develop into invasive squamous cell carcinoma if left untreated. It accounts for about 30% of non-melanoma skin cancers.
This starts in the melanocytes, the cells in skin that create pigment. Although it is less common, melanoma is considered the most serious type of skin cancer. This is because it is more likely to spread to other parts of the body, such as the lymph nodes, bones, liver, lungs, and brain, especially if not detected early.
What Causes Skin Cancer?
The main cause of all types of skin cancer is too much exposure to UV rays. Excessive exposure to UV light can damage skin cells and cause the skin to age prematurely. Overtime, it can lead to skin cancer.
Who is at risk?
Anyone can develop skin cancer, but people with certain skin types, characteristics, or medical conditions, are at greater risk.
- A lighter natural skin color
- Fair or freckled skin, especially if it burns easily
- Blue or green eyes
- Blond or red hair
- Lots of moles on the body
- Having a weakened immune system
- A personal history of sunburn
- A family history of skin cancer
- Certain skin conditions such as sunspots or actinic keratosis
What are the Symptoms of Skin Cancer?
Symptoms of skin cancer can vary depending on the type of skin cancer, including:
Basal cell carcinoma symptoms
Basal cell carcinoma usually develop on the face, head and neck, but they can occur anywhere on the body. Some common signs of basal cell carcinoma include:
- A sore that doesn’t heal
- A growth that has small blood vessels on the surface
- A sore that bleeds
- Flat, firm, pale or pearly areas
- Raised reddish patches that may itch
Squamous cell carcinoma symptoms
Squamous cell carcinoma often develop on areas exposed to the sun, including the face, ear, neck, lip and back of the hands. Some common signs of squamous cell carcinoma include:
- A sore that is crusty or bleeds easily
- A growth that looks like a wart
- A persistent small ulcer or thickened firm scaly skin on the lips
- A raised, scaly lump on the backs of the hands, legs, ears and lips
- Rough or scaly red patches with irregular borders
Melanomas can develop anywhere on your body. They most often develop on sun exposed areas but they can also occur in areas that are not exposed to sunlight, such as the soles of your feet, palms of your hands, and areas around genitals as well as anus. These hidden melanomas are more common in people with darker skin.
For melanoma specifically, you can use the “ABCDE rule” to look for some of the common signs of melanoma:
- “A” stands for asymmetry. Irregularly shaped moles or moles that differ from side-to-side.
- “B” stands for border irregularly. Moles with jagged or notched borders.
- “C” stands for color changes. Moles that have many colors or an uneven distribution of color.
- “D” stands for diameter. Moles that’s larger than 6 millimeters in diameter, or about the size of a pencil eraser.
- “E” stands for evolving. Moles that is changing in size, color, or shape.
Of course, not all moles and growths are cancerous. However, if you notice any of the above characteristics, consult with your doctor, as early detection greatly increases the likelihood of cure.
How is Skin Cancer Diagnosed?
If you have an abnormal area that might be skin cancer, your doctor will examine it to find out if it is cancer or some other skin conditions.
Your doctor or specialist will likely ask questions about your health history and examine your skin to look for any signs of skin cancer.
If they think you may have a skin cancer, they will usually take a tissue sample (biopsy) to confirm the diagnosis.
During this procedure, you will be given a local anaesthetic to numb the area and then the doctor will take a small piece of tissue from the spot or cut it out completely in a procedure called an excision.
The tissue that is removed will be sent to a laboratory, where a pathologist will examine it under a microscope. The results will be available in about a week.
What are the Treatment Options for Skin Cancer?
Once you have been diagnosed with skin cancer, your doctors will develop a treatment plan based on the type of skin cancer you have, the stage of the cancer (how far it has spread), and your general health conditions.
The most common treatments for skin cancer include:
Surgery is the most common treatment for skin cancer. For skin cancers that have not spread, surgery may be performed to remove the entire tumor, and no other treatment may be needed.
More aggressive skin cancers such as melanoma may require more extensive surgeries. Common surgical procedures include:
Surgical excisions can be performed to treat basal and squamous cell carcinomas as well as melanomas. During a surgical excision, the affected area is numbed with a local anesthetic. Your surgeon will then remove the cancer cells and a small amount of surrounding skin, known as the margin.
The margin is checked by a pathologist to make sure the cancer has been completely removed. If cancer cells are found in the margin, further surgery may be required. Most patients will have a scar the size of the incision after surgery.
Mohs surgery (Mohs’ micrographic surgery)
Mohs’ surgery is commonly used to treat basal cell and squamous cell carcinoma. It can also be used for cancers in areas that are difficult to treat, such as near the eye and on the nose, lips and ears.
In Mohs surgery, the surgeon removes the cancer little by little, checking each section of tissue under a microscope until no abnormal cells are visible.
This procedure reduces the amount of healthy skin that is removed while making sure all the cancer has been taken out.
Mohs’ surgery is not a common treatment because it is highly specialized surgery. It is only available at some private specialist practices and private hospitals. It costs more than other types of skin cancer surgery due to the time it takes and the equipment required.
In this procedure, you will be given a local anaesthetic by a dermatologist. When the area is numb, the doctor will scoop out or scrape away the cancer using a small, sharp, spoon-shaped tool called a curette. After that, the area is treated with an electric current through a needle-like electrode designed to kill remaining cancer cells and stop bleeding.
The procedure may need to be repeated 2 or 3 times to ensure the cancer is completely removed.
This method is usually simple and fast, which is effective for small basal cell carcinoma and squamous cell carcinoma.
Cryotherapy, or cryosurgery, uses liquid nitrogen to freeze and destroy the cancer cells. The treated area may swell and form a crust which will fall off after one to four weeks, depending on the area treated.
Cryotherapy may leave a small white scar on your skin. This is usually only used for small skin cancers or pre-cancerous lesions. It’s sometimes used for non-melanoma skin cancers that are at an early stage.
Skin grafts and skin flap
For large skin cancer, a bigger area of skin needs to be removed. In this case, a skin graft or skin flap may be performed to cover the wound.
The skin grafting process includes repairing the affected area using skin from another part of your body, such as your leg, arm and buttocks.
A skin flap is similar to a graft in that skin tissue is transplanted. The main difference is that a flap has its own blood supply, and that a graft does not.
With a flap, larger amounts of tissue can be used, including muscle if required. The option for a skin flap can be more complicated but has better cosmetic results. In some cases, additional cosmetic procedures may be required to improve appearance. Skin flap tends to be used where the appearance of the skin is most important, such as on your face.
Lymph node removal
If your doctor finds cancer cells in your lymph nodes, you may require additional surgery to remove them. This operation is typically performed by a plastic surgeon who specializes in the surgical management of cancers.
In this procedure, your doctor will remove one or more specific lymph nodes, known as sentinel lymph nodes, which directly receive the lymph fluid draining from the tumor. If no sign of cancer is found in the lymph nodes, no additional lymph node surgery is necessary.
If melanoma cells are found in one or more sentinel lymph nodes, the remaining lymph nodes in the region may be removed. This type of operation is frequently performed on melanoma patients.
Chemotherapy uses drugs to kill cancer cells. A drug that is commonly used to treat skin cancer is called 5-Fluorouracil (Efudix cream). The chemotherapy cream is usually applied once or twice a day for several weeks. Your doctor may advise you to cover the area with a waterproof dressing after putting on the cream.
The treatment should make the skin red and inflamed. Once the area becomes sore and weepy, the treatment will be stopped. This is usually after 3 to 4 weeks, depending on where it is on your body. It may be less if it is on your face, or longer for other areas. If the area is very sore, your doctor can prescribe a steroid cream to help.
Chemotherapy can also be given in a vein in your arm or leg in a procedure called isolated limb perfusion. During this procedure, blood in your arm or leg isn’t allowed to travel to other areas of your body for a short time so that the chemotherapy drugs travel directly to the area around the melanoma and don’t affect other parts of your body.
Radiotherapy uses X-rays to destroy cancer cells. It is often used to treat cancer in areas that are difficult to treat with surgery, such as on the face, or cancers that have grown deeply into the skin.
Radiotherapy is usually given 5 times a week for 4-8 weeks. After a week or two of radiation therapy, the treated skin will be red and inflamed. If radiation therapy is used around the head, side effect, such as hair fall, may occur. However, these side effects usually go away once the treatment is finished.
Immunotherapy is a drug treatment that stimulates the body’s immune system to destroy cancer cells.
The immune system usually prevents cancers from developing because of its ability to detect and eliminate abnormal cell growth. But sometimes the body’s immune system may not be strong enough to fight the cell growth that causes cancer. Cancer cells may also masquerade as healthy cells, thus avoiding the immune system.
Immunotherapy can boost the immune system to work better against cancer or remove barriers to the immune system attacking the cancer.
Checkpoint inhibitors are immunotherapy drugs that work by targeting signaling proteins that allow cancer cells to disguise themselves as healthy cells.
The Immunotherapy drugs are usually given with an injection into a vein (intraveneously). Most doctors prefer to provide the drugs every 2 to 3 weeks in a repeating cycle, which is then followed by a period of rest. This cycle will continue until the cancer is gone or significantly reduced.
The side effects of checkpoint immunotherapy are different from those of other cancer treatments. Common side effects may include skin rash, fatigue, abdominal pain, diarrhea, nausea, and joint pain.
Photodynamic therapy (PDT) uses a drug and a special type of light to kill cancer cells. It involves using a cream that makes the skin highly sensitive to light. After the cream has been applied, a strong light source is shone on to the affected area of your skin, which kills the cancer.
For skin cancers, PDT usually needs to be repeated after two weeks. Side effects include redness and swelling, which usually ease after a few days.