Skin cancer is the most common type of cancer worldwide. An uncontrolled growth of mutated or genetically defective skin cells, skin cancer occurs when these cells rapidly multiply and form tumors. The DNA damage causing mutation and genetic defects to skin cells is often the result of ultraviolet radiation due to unprotected exposure to sunlight or tanning beds.
There are three primary types of skin cancers, including melanoma, basal cell carcinoma, and squamous cell skin cancers. Malignant melanoma is the most difficult of the three to treat, but early diagnosis can provide advantages during treatment that increase the survival rate.
Definition & Facts
Abnormal changes in cells of the outer layer of skin are often cancerous with skin cancer being responsible for 75 percent of global cancer diagnoses. Most cases of cancer are curable, but the number of incidences are rising despite preventability. Protecting skin from ultraviolet radiation is the primary means of preventing the disease.
Men are affected by skin cancer three times more often than women. As people age, risk also increases. The vast majority of those diagnosed are between the ages of 45 and 54, although this is gradually changing with the frequency of the disease's occurrence increasing among younger people. Factors that increase the likelihood of getting skin cancer include:
- Sun overexposure without sunscreen protection or other covering of skin
- Genetic factors, when relatives have had skin cancer
- Geography, in regard to sunny climates
- Race, with Caucasians more frequently diagnosed
Because all malignant skin tumors eventually become visible to the naked eye on the surface of skin, this form of cancer is considered one of the most detectable for early treatment.
Symptoms & Complaints
Basal cell carcinoma is a type of skin cancer most often occurring where sun exposure does occur, such as on the face or neck. These spots appear like a waxy or pearly bump, or resemble a flat, flesh-colored scar.
Squamous cell carcinoma most often occurs where sunlight reaches skin on fair complected patients, on areas like the hands, face and ears. For people with darker skin, squamous cell carcinoma usually develops on areas of the body shielded from the sun. These spots appear as firm, red nodules or flat lesions with scaly, crusty surfaces.
Melanoma appears anywhere on the body, regardless of whether or not sun exposure is frequent on that area of the body. It can grow in normal skin areas or those where an existing mole turns into a cancerous one. The face and trunk are where men usually find melanoma growths, whereas women tend to find these spots on their legs. Like the other two forms of skin cancer, melanoma also appears on palms and soles of the feet on people with dark complexions.
Specific symptoms of melanoma include:
- Large brown spot with dark specks
- A mole that changes in size, texture or color
- A mole that bleeds
- Small lesion or mole with undefined border and areas that appear red, blue, black or white
- Dark lesions on mucous membranes of the nose, mouth, vagina, or anus
- Dark lesions on the palms, soles of feet, fingertips or toes
Three other forms of skin cancer that are less common include:
- Kaposi's sarcoma, usually appearing in people with weakened immune systems
- Merkel-cell carcinoma, usually occurring just beneath skin and in follicles
- Sebaceous gland carcinoma, an aggressive form of skin cancer starting in the sebaceous glands
Skin cancer occurs from mutations or changes in DNA of skin cells, particularly in the epidermis. The mutated cells then grow rapidly and create a mass of cancerous cells. Exposure to ultraviolet light is widely known to cause skin cancer. Other factors also may cause the skin cell mutations, because not everyone developing skin cancer has experienced frequent or prolonged exposure to sunlight. It is believed that other causes may include exposure to toxins or immune system disorders. Factors creating higher risk of skin cancer development include:
- Fair skin, as lighter pigmentation provides less UV radiation protection
- History of sunburns
- High frequency of exposure to the sun
- Tanning in tanning beds or booths
- Living in sunny, high altitude climates
- Having many moles, which can evolve into cancerous lesions
- Having precancerous lesions from sun damage
- Family history of skin cancer
- Personal history of skin cancer
- Weakened immune system
- Radiation exposure
- Exposure to toxins, such as arsenic
Diagnosis & Tests
Diagnosis of skin cancer often includes a doctor's close examination of the patient's skin and review of any suspicious looking moles or lesions. The doctor may sample the skin as part of a biopsy, to have suspicious spots examined under a microscope. Additional tests may include an imaging test such as a CT scan or MRI of lymph nodes or a lymph node biopsy to determine whether these nodes have been affected by the cancer growth. The stage of the cancer's growth, indicated on a scale of I through IV, determines which treatment options will be used.
Treatment & Therapy
Precancerous lesions and skin cancer are treated through a variety of methods, according to the size, type, depth and location of the lesions' growth. For small and isolated skin cancers, sometimes removing the negative cells through a biopsy is the only necessary treatment to stop progression. When additional treatment is needed, the doctor may perform any of the following:
- Freezing of lesions or small early cancers with liquid nitrogen
- Excision of the skin cancer as part of a surgery to remove the cancer growth and some surrounding skin
- Mohs surgery, for larger, difficult skin cancers on areas of the body with little extra skin, such as the nose
- Curettage scraping away of growth layers, followed by electrodesiccation or cryotherapy of the area
- Radiation therapy
- Photodynamic therapy, a combined treatment using lasers and medications
- Biological therapy, using the body's own immune system to fight the cell growth
Prevention & Prophylaxis
Protective clothing and hats also help shield delicate skin from damaging UV rays. Avoiding suntanning beds and medications causing photosensitivity are also means of preventing skin cancer. Skin should be checked often for any changes in appearance, texture or mole growth, with any changes immediately examined by a dermatologist.