About Different Types of Skin Cancer: Melanoma, Basal Cell Carcinoma, Squamous Cell Carcinoma
Skin cancer is the most commonly diagnosed cancer in the United States. The disease is grouped into two categories based on the type of cell from which the cancer originates – melanoma and non-melanoma; the latter includes basal cell carcinoma and squamous cell carcinoma.1 It is estimated that one in five Americans will develop some form of skin cancer during his or her lifetime.2 Most cases can be cured if caught and treated when the disease is limited to a small area of the skin. However, if the disease advances by spreading on the skin or into the body, it may have devastating consequences and could become deadly.3
Layers of the Skin 1
The skin is composed of three layers, the epidermis, dermis and hypodermis (or subcutis). The epidermis, the top layer of the skin, is made up of many different cell types that give the skin structure and color. Basal cells are involved in regenerating skin and melanocytes produce the skin’s pigment giving it color.
Melanoma is the less common, but more serious category of skin cancer that starts in the skin’s pigment producing cells known as melanocytes.3 According to the American Cancer Society, fewer than five percent of skin cancer diagnoses are melanoma, but melanoma accounts for a large majority of skin cancer deaths.3 Cases of melanoma have been increasing for at least 30 years.3 In 2013, it is estimated that more than 76,000 people will be diagnosed with melanoma and nearly 9,500 people will die from the disease.3
The majority of melanoma cases are diagnosed and treated when the disease is on a small area of the skin.3 However, if the cancer spreads to other tissues and organs and is classified as advanced, a person’s prognosis becomes worse and the disease is potentially deadly. Only 15 percent of people with advanced melanoma are expected to live for five years or longer.3
- Common treatments include surgery, chemotherapy, immunotherapy and radiation. However, treatment varies based on the stage of the disease. Early-stage (Stage I) melanoma is often treated with surgery, while advanced disease has few treatment options available and is not curable.3,4
- Current treatments for advanced melanoma include targeted therapy, chemotherapy, surgery, radiation and immunotherapy.3
Basal Cell Carcinoma (BCC)
The most common type of skin cancer is basal cell carcinoma (BCC), a slow-growing disease that originates in the skin’s basal cells, which replace old cells that wipe away from the surface of the skin.1,2 Approximately 80 percent of non-melanoma skin cancers diagnosed are BCC.1
If it is found early and treated, BCC is very likely to be cured.3
In rare cases, if it is not treated or comes back after treatment, it can spread or grow deep under the skin’s surface into surrounding tissue (locally advanced). Some people may have lesions in areas such as the eyes, nose or ears, which may be disfiguring or result in a loss in function. The disease can also, in rare cases, spread to other parts of the body (metastatic).1,5
The length of time that people may live after BCC has spread to other parts of the body varies. In metastatic disease, one year survival is at 76 percent. However, for BCCs that spread to distant areas of the body (metastases), the likelihood of survival is lower than for those that spread to the lymph nodes-only (69 percent vs. 87 percent).6
- Common treatments include surgery, radiation, immunotherapy, chemotherapy, topical therapy or light therapy.1,7
- Current treatments for advanced forms of BCC include targeted therapy, surgery, radiation and chemotherapy.8
Squamous Cell Carcinoma
Squamous cell carcinoma (SCC) originates from squamous cells, which are found in the tissue that forms the surface of the skin.1 Like BCC, most cases of SCC may be cured if identified and treated when it is restricted to a small area of the skin.3
- Current treatments include surgery, radiation, chemotherapy or topical therapy.1
Rare types of non-melanoma skin cancer that account for less than one percent of all types of skin cancer, include Merkel cell carcinoma, Kaposi sarcoma, cutaneous lymphoma, skin adnexal tumors and various other types of sarcoma.1
Skin Cancer Symptoms
Risk factors and symptoms vary between different types of skin cancer, but can generally include:1
- Ultraviolet (UV) radiation – Prolonged exposure to UV rays found in the sun or tanning lamps and booths is thought to be a major risk factor for melanoma and BCCs1
- Weakened immune system – Medications or conditions that suppress the immune system may increase the risk of skin cancer. For example, people taking corticosteroids or who have a weakened immune system may be at increased risk.1
- Previous skin cancer history – People who have had skin cancer before have a higher chance of developing another one1
- Skin color – light or fair skin color is associated with a higher risk for melanoma and other skin cancers1
- A new mole or lesion on the skin, or a mole that changes in size, shape, or color and looks different from other moles on the body1
- For Melanoma – warning signs can include one half of the mole looking different from the other half, irregular edges, different colors on a single mole, a very large mole, or one that is bleeding, oozing or swells4
- For BCC – flat, firm, pale areas of the skin or small, raised, pink or red, translucent, shiny, waxy skin areas that may bleed after a minor injury or visible abnormal blood vessels with discoloration on the skin or an oozing crusted area of the skin1
Early Stage Melanoma
Early Stage BCC
Early stage skin cancer looks like an abnormal mole or a lesion that is restricted to a small area of the skin.
Because prolonged exposure to UV rays from sunlight increases the risk of getting skin cancer, the American Cancer Society recommends that skin should be protected from intense exposure by clothing, sunglasses and sunscreen that is a sun protection factor (SPF) of 30 or greater.3
1 American Cancer Society. Basal and Squamous Cell. Available at http://www.cancer.org/cancer/skincancer-basalandsquamouscell/detailedguide/skin-cancer-basal-and-squamous-cell-what-is-basal-and-squamous-cell Accessed August 1, 2013.
2 Thomas V, Aasi S, Wilson L et al. In: Devita VT, Lawrence TS, Rosenberg SA eds. Cancer: Principles and Practice of Oncology. Vol2. 8th ed. Philadelphia, Pa: Lippincott Williams and Wilkins; 2008: 1863-1889.
3 American Cancer Society. Cancer Facts & Figures 2013. http://www.cancer.org/research/cancerfactsstatistics/cancerfactsfigures2013/index. Accessed June 1, 2013.
4 American Cancer Society. Skin Cancer: Melanoma. http://www.cancer.org/acs/groups/cid/documents/webcontent/003120-pdf.pdf.Accessed August 1, 2013.