Skin Cancer—Overview

(Basal Cell Carcinoma; Squamous Cell Carcinoma)


Skin cancer is the growth of cancer cells that start in the skin.
The 2 most common kinds of skin cancer are:
It is important that skin cancers be found and treated early. If left untreated, they can quickly invade and destroy nearby tissue.
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Cancer occurs when skin cells in the body divide without control or order. When cells keep dividing uncontrollably when new cells are not needed, a mass of tissue forms. This is called a growth or tumor. Unlike benign tumors, malignant tumors can invade nearby tissues and spread to other parts of the body.

Risk Factors

Basal and squamous cell cancers are more common in men and in people over 50 years old. These cancers are most likely to occur in people with:
Other factors that may increase the chance of skin cancer include:


Most skin cancers do not cause symptoms. When they do appear, the most common first symptom is a change in the skin.
Basal cell carcinoma may appear as a:
Squamous cell carcinoma may appear as a:
Skin cancers can occur anywhere, but are more common on places that are exposed to the sun.


The doctor will ask about your symptoms and medical history. A physical exam will be done.
You may have a biopsy. The sample can then be examined for under a microscope for the presence of cancer cells.
In cases where the growth is large, or has been present for a long time, the lymph nodes in the area will be checked. More tests may be advised to determine if the cancer has spread to other parts of the body.


The doctor will discuss a treatment plan, which may include one or more of the following:


Many skin cancers can be cut from the skin quickly and easily. In fact, the cancer is sometimes completely removed during biopsy and no further treatment is needed. Surgical techniques include:
Curettage and Electrodesiccation
This involves scooping the cancer out with a curette, an instrument with a sharp, spoon-shaped end. The area is treated with an electric current to control bleeding. This also kills any cancer cells remaining around the edge of the wound. This technique is used for small or superficial cancers.
Mohs Surgery
Mohs surgery is the removal of all of the cancerous tissue. The surgeon will try to remove as little healthy tissue as possible. This method is used to remove:
  • Large tumors
  • Tumors in hard-to-treat places
  • Tumors of undetermined shape and depth
  • Cancers that have recurred
The procedure is done by specially trained dermatologic Mohs surgeons. The cancer is shaved off one thin layer at a time. Each layer is checked under a microscope for cancer cells until the entire tumor is removed.
Liquid nitrogen is used to freeze and kill the abnormal cells. After the area thaws, the dead tissue falls off. More than one freezing may be needed to remove the growth completely. This method may be used to treat precancerous skin conditions (actinic keratoses) and certain small or superficial skin cancers.

Laser Therapy

Laser therapy uses a narrow beam of light to remove or destroy cancer cells. This method is sometimes used for cancers in the outer layer of skin.

Radiation Therapy

Radiation therapy uses radiation to kill cancer cells and shrink tumors.

Topical Chemotherapy

Topical chemotherapy is the use of drugs to kill cancer cells. The drugs can be creams or lotions. This method is successful in treating precancerous conditions and cancers limited to the outer layer of the skin. The most common topical chemotherapy used is a form of 5-fluorouracil (5-FU).


Medications, such as imiquimod, increase your body's own response to fight the cancer cells.


To help reduce the chance of skin cancer:
Finding skin cancer early offers the best chance for a cure. In general:


American Academy of Dermatology

American Cancer Society


Canadian Cancer Society

Canadian Dermatology Association


Alberta Provincial Cutaneous Tumour Team. Prevention of skin cancer. Edmonton (Alberta): CancerControl Alberta; 2013 Feb. 27 p. (Clinical practice guideline; no. CU-014). Available at: Accessed February 25, 2015.

Basal cell carcinoma of the skin. EBSCO DynaMed website. Available at: Updated December 18, 2014. Accessed February 25, 2015.

General information about skin cancer. National Cancer Institute website. Available at: Accessed February 25, 2015.

Skin cancer: Basal and squamous cell. American Cancer Society website. Available at: Updated February 20, 2014. Accessed February 25, 2015.

Squamous cell carcinoma (SCC). EBSCO DynaMed website. Available at: Updated January 16, 2015. Accessed February 25, 2015.

Sunscreen FAQs. American Academy of Dermatology website. Available at: Accessed February 25, 2015.

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