Skin cancer is the most common form of human cancer, outnumbering the total incidence of breast, prostate, lung and colon. The three most common types of skin cancer are basal cell carcinoma, squamous cell carcinoma and malignant melanoma. About 50% of Americans who reach age 65 will be diagnosed with either basal cell carcinoma or squamous cell carcinoma. Melanoma accounts for less than 1% of skin cancer cases, but is estimated to kill over 10,000 people in the US annually. Skin cancer is the most easily treated form of cancer with early diagnosis and treatment.
Our board certified providers at Knoxville Institute of Dermatology specialize in skin cancer diagnosis and treatment, including mohs micrographic surgery. If you have a suspicious area on your skin or would like a total body skin exam, contact our office today.
What is skin cancer?
A skin cancer is a tumor in which there is uncontrolled proliferation of any of the skin cells, whereas the normal process of regeneration of skin involves replication of the cells in a controlled fashion. Each subtype of skin cancer has unique characteristics. The most common forms of skin cancer are:
- Basal cell carcinoma (BCC)
- Squamous cell carcinoma (SCC), including keratoacanthoma
- Superficial basal cell carcinoma
- Intraepidermal squamous cell carcinoma or Bowen disease (pre-cancerous, in-situ squamous cell carcinoma) and actinic keratoses
- Melanoma in situ
Who gets skin cancer?
Skin cancer most commonly affects older adults but it can also affect younger adults, and rarely, children.
- Skin cancer tends to affect individuals with fair skin (Fitzpatrick skin phototype I, II and III), although people with darker skin can also develop skin cancer.
- People who have had a skin cancer have an increased risk of developing other skin cancers.
- A family history of skin cancer also increases risk.
What causes skin cancer?
The common forms of skin cancer listed above are related to exposure to ultraviolet radiation (from sunlight or tanning beds) and the effects of ageing. Other risks include:
- Smoking (especially for SCC)
- Human papillomavirus infection (genital warts), particularly for mucosal sites such as oral mucosa, lips and genitals
- Immune suppression, for example in patients who have received an organ transplant and are on azathioprine and/or cyclosporin
- Human immunodeficiency virus infection (HIV)
- Exposure to ionizing radiation
- Exposure to certain chemicals, such as arsenic and coal tar
- Longstanding skin disease such as lichen sclerosus, lupus erythematosus, linear porokeratosis or cutaneous tuberculosis
- A longstanding wound or scar, eg, from thermal burn (a Marjolin ulcer).
What are the clinical features of skin cancer?
Skin cancers generally appear as a lump or nodule, an ulcer, or a changing lesion.
What are the complications of skin cancer?
Skin cancer can usually be treated and cured before complications occur. Signs of an advanced, aggressive or neglected skin cancer may include:
- Spread of the tumor to lymph glands and other organs such as liver and brain (metastasis).
How is skin cancer diagnosed?
Skin cancers are generally diagnosed clinically by a dermatologist or family doctor, when learning of an enlarging, crusting or bleeding lesion. The lesion will be inspected carefully, and ideally, a full skin examination will also be conducted.
- Dermatoscopy (a special magnifying light) may be used to confirm the diagnosis, to detect early skin cancers, and to exclude benign lesions.
- A partial skin biopsy may be taken in cases of suspected non-melanoma skin cancer to confirm the diagnosis.
- A complete excision is usually undertaken to make a diagnosis if melanoma is suspected, as partial biopsy can be misleading in melanocytic tumors.
- The diagnosis is confirmed in the laboratory by a histopathologist. It can take a few days for the report to be issued, or longer if special tests are required.
What is the treatment for skin cancer?
Early treatment of a skin cancer usually cures it. The majority of skin cancers are treated surgically, using local anesthetic to numb the skin. Surgical techniques include:
- Excision biopsy
- Mohs surgery
Treatment options for superficial skin cancers include:
- Minor surgery including curettage and diathermy/cautery and electrosurgery
- Topical therapy such as fluorouracil cream, imiquimod cream or ingenol mebutate gel
- Photodynamic therapy (photosensitizing solution plus light)
Patients with skin cancer may be at increased risk of developing other skin cancers. They may be advised to:
- Practice careful sun protection, including regular application of sunscreens
- Learn and practice self skin examination
- Have regular skin checks
- Seek medical attention if they notice any changing or enlarging skin lesions
- Take nicotinamide (vitamin B3) to reduce the numbers of nonmelanoma skin cancers.