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by LaRusso L

Skin Cancer—Overview

(Basal Cell Carcinoma; Squamous Cell Carcinoma)

Definition

Skin cancer is the growth of abnormal skin cells. These abnormal cancer cells grow out of control and damage nearby healthy tissue. Some types of skin cancer can also spread to other parts of the body. There are different type of skin cancer based on the type of skin cells that the cancer starts in. The three most common kinds of skin cancer are:
Most skin cancers when found early can be cured. Certain skin cancers like melanoma and merkel cell carcinoma can be fatal if found in late stages.
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Causes

Cancer occurs when cells in the body divide without control or order. This uncontrolled growth is caused by damage to DNA in the cells. This damage may be caused by genetics, the environment like sun exposure, or a combination of both. When cells grow when they are not needed they begin to build up and form a tumor. Malignant tumors (cancer) do not just grow in place but also invade nearby healthy tissues. Eventually, some of the cancer cells can break off and travel to other parts of the body.
UV radiation from the sun or tanning beds can cause damage to DNA of skin cells. The damage may occur after a lifetime of exposure or from brief intense exposures like sunburns.

Risk Factors

While skin cancer can develop in anyone it is more likely to develop in people with:
  • Fair skin that freckles easily
  • Red or blonde hair
  • Light-colored eyes
  • Caucasian skin
Other factors that may increase the chance of skin cancer include:
  • Personal history of skin cancer
  • Exposure to ultraviolet radiation from the sun or artificial radiation from a tanning bed
  • Excessive sun exposure without protective clothing or sunscreen
  • Skin damage from burns or infections
  • Exposure to arsenic, industrial tar, coal, paraffin, and certain types of oil
  • Radiation therapy
  • Light treatments for psoriasis , especially psoralen ultraviolet A (PUVA)
  • Suppressed immune system from illness or medications
  • Certain genetic diseases, such as basal cell nevus syndrome or xeroderma pigmentosum

Symptoms

Skin cancers first symptoms are a change in the skin. One type of change known as actinic keratosis is considered precancer change. This scaly, crusty change to skin can develop into skin cancer if left untreated.
Skin changes caused by cancer will depend on the type of skin cancer, for example:
Basal cell carcinoma may appear as a:
  • Slowly expanding, painless growth
  • Bleeding scab or sore that heals and recurs
  • Flat, firm, pale area
  • Small, raised, pink, red, or pearly areas that may bleed easily
  • Large oozing, crusted area
Squamous cell carcinoma may appear as a:
  • Growing lump with rough, scaly, or crusted surfaces
  • Slow-growing flat, reddish patch in the skin
  • Recurrent, nonhealing ulceration or bleeding
Skin cancers can occur anywhere, but are more common on places that are exposed to the sun.
Finding skin cancer early offers the best chance for a cure.
  • Report any skin changes or symptoms (listed above) when they appear, so they can be examined by a doctor.
  • If you have fair skin, have your skin regularly checked by a doctor.
  • Ask the doctor about regular skin screenings you can do at home.

Diagnosis

The doctor will ask about your symptoms and medical history. A physical exam will be done.
If the doctor suspects cancer a biopsy will be done. A sample of the skin will be removed and examined for the cancer cells.
The lymph nodes may be checked if the growth is large. Cancer in the lymph nodes means the cancer may have spread. More tests will be needed if cancer is found in the lymph nodes.

Treatment

Treatment will depend in the type of cancer, the size of the growth, and your overall health. Options may include:

Surgery

Many skin cancers can be cut from the skin. Some skin cancer can be completely removed during biopsy. If it is completely removed no further treatment is needed. Surgical techniques include:
Simple Excision
A surgical knife is used to cut out the lesion.
Curettage and Electrodesiccation
The cancer is scooped out with a sharp, spoon-shaped end. The tool uses a mild electric current to stop bleeding. The current also kills any cancer cells that may have been left around the edge of the wound. This technique is used for small skin cancers that are not deep.
Mohs Surgery
Mohs surgery shaves off thin layers of skin. The doctor will continue until the removed layers show no signs of cancer. The goal is to remove as little healthy tissue as possible while making sure all the cancer is gone. 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 surgeons.
Cryosurgery
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 cancer completely. This 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 medications to kill cancer cells. The medication can be creams or lotions. This method is successful in treating precancerous conditions and cancers limited to the outer layer of the skin.

Immunotherapy

Immunotherapy uses medications that help your immune system fight the cancer.

Prevention

To help reduce the chance of skin cancer:
  • Avoid spending too much time in the sun.
  • Avoid exposing your skin to the sun between 10:00 AM and 2:00 PM standard time, or 11:00 AM to 3:00 PM daylight saving time.
  • Protect your skin from the sun with clothing. Wear a shirt, sunglasses, and a hat with a broad brim.
  • Use broad-spectrum (UVA and UVB) sunscreens with a sun protection factor (SPF) of 30 or more on skin that will be exposed to the sun.
  • Use a protective lip balm.
  • Wear sunglasses with 99% or 100% UV absorption to protect your eyes.
  • Do not use sun lamps or tanning booths.

RESOURCES

American Academy of Dermatology
http://www.aad.org
American Cancer Society
http://www.cancer.org

CANADIAN RESOURCES

Canadian Cancer Society
http://www.cancer.ca
Canadian Dermatology Association
http://www.dermatology.ca

References

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: http://www.guideline.gov/content.aspx?id=48130#Section420. Accessed February 25, 2015.
Basal cell carcinoma of the skin. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T113813/Basal-cell-carcinoma-of-the-skin. Updated July 21, 2016. Accessed September 23, 2016.
Cutaneous squamous cell carcinoma (SCC). EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T116909/Cutaneous-squamous-cell-carcinoma. Updated August 5, 2016. Accessed September 23, 2016.
General information about skin cancer. National Cancer Institute website. Available at: http://www.cancer.gov/types/skin/patient/skin-treatment-pdq. Accessed February 25, 2015.
Skin cancer: Basal and squamous cell. American Cancer Society website. Available at: http://www.cancer.org/acs/groups/cid/documents/webcontent/003139-pdf.pdf. Updated February 20, 2014. Accessed February 25, 2015.
Sunscreen FAQs. American Academy of Dermatology website. Available at: https://www.aad.org/media/stats/prevention-and-care/sunscreen-faqs. Accessed February 25, 2015.

Revision Information

  • Reviewer: EBSCO Medical Review Board James Cornell, MD
  • Review Date: 03/2017
  • Update Date: 03/14/2017
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