Skin cancer results from the abnormal growth of skin cells, most often developing on skin exposed to the sunrays. It can also occur on areas of skin not ordinarily exposed to sunlight.
Our skin is made up of three layers. The epidermis, the top layer of the skin is responsible for protecting our body. It is thin in some parts and thicker on others. The second layer is called the dermis. This layer is thicker than the epidermis. It contains the sweat glands (which help your body stay cool), nerve endings (which give us a sense of touch, temperature, pressure) hair roots & oil glands (keep the skin moist) and blood vessels (to supply nutrition to the skin). The third and the lowermost layer of the skin is the subcutaneous fat layer, which attaches the skin to the body; helps control body temperature and acts as a fat reserve.
The abnormal and uncontrolled growth of cells usually happens in the epidermis, which is the outermost layer of your skin. It is essentially the DNA damage that triggers mutations, which leads to skin cancers
- Exposure to UV Radiation: The ultraviolet radiation found in the sun or tanning beds can be harmful to the skin and result in DNA damage. Going out in the sun for long periods without a protective cover (clothes or sunscreens) can increase the risk.Having sunburns mean that your skin is not able to protect itself from the sun, which puts you at a higher risk of cancer than others
- Fair Skin: Anyone can get skin cancer, regardless of his or her skin colour. However, melanin (the pigment that is responsible for skin colour) protects the skin from UV rays. Therefore, a lighter skin puts one at a higher risk for skin cancer.
- Moles: If you have moles of irregular shape and an unusual number of moles, you may be at a risk for cancer.
- Precancerous skin lesions: Skin lesions known as actinic keratoses can increase your risk of developing skin cancer. These precancerous skin growths typically appear as rough, scaly patches that range in colour from brown to dark pink. They're most common on the face, head and hands of fair-skinned people whose skin has been damaged by UV rays form sunlight.
- Family History: Having a positive family history of skin cancer, can increase your risk of getting skin cancer.
- Weak immune system: People with weakened immune systems have a greater risk of developing skin cancer. This includes people living with HIV/AIDS and those taking immunosuppressant drugs after an organ transplant.
- Exposure to radiation. People who received radiation treatment for skin conditions such as eczema and acne may have an increased risk of skin cancer, particularly basal cell carcinoma.
- Exposure to certain substances. Exposure to certain substances, such as arsenic, may increase your risk of skin cancer.
There are the following types of cancer:
- Basal cell carcinoma: This cancer develops in the lowermost layer of the epidermis. These usually occur on skin parts, which are exposed to UV rays. These cancers grow slowly and are less likely to metastasize to other parts of the body. Basal Cancers have a tendency to recur.
- Squamous cell carcinomaThese account for almost 20% of non-melanoma cancers of the skin. Squamous cells are the flat cells on the outermost layer of the skin. These are more likely to be found in areas exposed to the sun, such as head, neck or arms. They usually metastasise to surrounding lymph nodes and if left untreated spread to distant organs can also occur.
- Melanoma:Malignant transformation of melanocytes gives rise to melanoma. Melanocytes are the skin cells that are responsible for producing melanin; a pigment accountable for skin colour, which protect us from the UV rays. These cells darken (as they release more melanin) on exposure to the sun as a response to protect the skin from harmful effects of UV rays. These are aggressive tumors.
- Merkel cell carcinoma:This is an aggressive form of cancer that originated in the Merkel cells. These cells are responsible for touch sensation. They are more common in areas like head, scalp or face. They have the tendency to metastasize to the brain, bones, liver and/or lungs
- Rare skin cancers: These include Kaposi’s sarcoma, sebaceous gland carcinoma, cutaneous lymphoma etc.
Different types of skin cancers may exhibit different symptoms.
- Basal cell carcinoma: A translucent, skin-coloured or pink growth or bleeding or scabbing sore. It usually appears near the face or ears.
- Squamous cell carcinoma: A firm, red bump or a flat sore with a scaly crust or a non-healing ulcer.
- Melanoma: A change in an existing mole (increase in size with irregular borders, bleeds on scratching, irregular surface, change of colour) or a new pigmented or abnormal growth on your skin
These lesions and growths and moles can appear in any different form or characteristic, and hence it is best advised to consult a doctor, if you are experiencing any of these symptoms.
1. Physical examination: A through physical examination will be carried out after obtaining a detailed history of your symptoms.
2. Biopsy: Biopsy is performed to determine the exact type of skin cancer. Depending on the size of the growth or suspicious area, biopsy can be: incisional biopsy (a small piece is taken after administering local anaesthesia and sent for histopathological reporting) or an excisional biopsy (for smaller growths or suspicious areas, the entire area is removed under local anaesthesia)
3.CT scan: In advanced case of squamous cell carcinoma, a CT scan of the chest, abdomen and pelvis may be done to determine spread of cancer into lymph nodes (pelvic, abdominal or mediastinal) or to other organs. This helps to correctly stage the disease; which in turn will help decide the best treatment sequence for a given patient.
4. PET CECT scan: A PET CT scan is usually advised to determine stage of disease in patients with melanoma.
Surgery: Surgery involves removal of the primary skin tumor with a margin of normal tissue. This can be achieved by various procedures depending on the size of the skin cancer
- Excision biopsy
- Mohs micrographic surgery: involves removal of the tumor layer by layer to preserve the maximum skin possible. This is preferred in areas where skin preservation is necessary
- Amputation: Sometimes amputation of the affected part may be needed to completely remove the cancerous growth
- Lymph node dissection: Is usually carried out in cases of squamous cell carcinomas and melanomas, to remove the draining lymph nodes.
Non-surgical options: These include
- Cryosurgery: It makes the use of liquid nitrogen to freeze the cancerous cells until the tissue is dead.
- Cryotherapy is a procedure where layers of cancer cells are scraped off using a circular blade and electric needles are used to destroy remaining cancer cells.
- Anti-cancer creams: Cancers that are limited to upper layers of the skin can be treated using creams that contain anti-cancer agents.
- Photodynamic therapy: It uses a combination of laser light and drugs to treat superficial skin cancers
Radiation therapy:It makes the use of high energy rays to target and destroy the cancer cells. Radiation treatment may be suggested after surgery as adjuvant treatment with or without chemotherapy in cases of squamous cell carcinoma.
Chemotherapy: Chemotherapy in the form of injections may be suggested depending on the stage of disease in cases of squamous cell carcinoma. It is done in 2 -3 weekly cycles, for a total of 6 cycles. It can also be recommended during radiation treatment; called as concurrent chemo-radiotherapy.
Biological therapy or immunotherapy:In advanced cases of melanoma, biological therapy or immunotherapy may be suggested for treatment. Immunotherapy targets the cells, which affect the body’s immune response and helps the body in killing cancer cells.
Targeted therapy:Targeted therapy uses drugs to target specific proteins within the cancer cells, to kill them. For example, Vemurafinib, Dabrafenib targeting BRAF protein in melanoma cells may be suggested in treatment of advanced cases of melanoma.
Most of the skin cancer types can be prevented. Some of the preventive measures are:
- Avoid going out in the sun for longer periods of time when the sun is at its peak.
- If you have to go in the sun, make sure to wear protective clothing.
- Use sunscreens. You may want to use a broad-spectrum sunscreen (with SPF more than 30) on all your exposed skin when out in the sun.
- Avoid tanning beds as they emit UV radiations.
- Do not use any type of ‘sun sensitizing’ medications without proper consultation.
- If you are at a higher risk than others are, get yourself tested and screened regularly. You may also do a self-examination by standing in front of the mirror and checking any changes on your skin or in pre-existing moles.