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Skin Cancer—Overview

(Basal Cell Carcinoma; Squamous Cell Carcinoma)

Definition

Skin cancer is the growth of abnormal skin cells. These 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 types of skin cancer, the three most common kinds are:

Most skin cancers can be cured when found early. Certain skin cancers can be fatal if found in late stages.

Causes

Cancer occurs when cells in the body grow without control or order. This uncontrolled growth is caused by damage to DNA in the cells. Your genes and the environment (such as sun exposure) probably both play a role. This extra growth builds up and forms a tumor. Cancer tumors will also invade nearby healthy tissues. Eventually, some of the cancer cells can break off and travel to other parts of the body.

UV radiation damages the DNA of skin cells. Both the sun and tanning beds make these UV rays. The damage may build up over a lifetime. It can also happen after a 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
  • Blue or green eyes
  • Light natural skin color

Other factors that may increase the chances of skin cancer:

  • Personal history of skin cancer
  • Family 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 or industrial coal tar
  • Radiation therapy
  • Light treatments for psoriasis, especially psoralen ultraviolet A (PUVA)
  • Suppressed immune system from illness, medicine, or an organ transplant
  • Certain genetic diseases, such as basal cell nevus syndrome or xeroderma pigmentosum

Symptoms

The first symptoms of skin cancers are a change in the skin. One type of change known as actinic keratosis. It is considered a precancerous 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 any of the following:

  • 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 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 symptoms and past health. 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 nearby lymph nodes (glands) 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.

Tests will be reviewed to determine the stage of cancer. Skin cancer may be stage 0 to 4. Stage 0 and 1 cancers only affect the local area. Stage 4 cancer has spread to other areas of the body. Staging will help to guide treatment.

Treatment

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

Surgery

Many skin cancers can be fully cut out of the skin. Some skin cancer can be completely removed during a biopsy. Larger skin cancers may be removed by surgery after a biopsy finds cancer. If skin cancer is completely removed, no further treatment is needed. Surgical techniques include:

  • Simple excision —A scalpel is used to cut out the lesion.
  • Curettage and electrodesiccation —The cancer is scooped out with a sharp, spoon-shaped tool. It is used for small skin cancers that are not deep.
  • Mohs micrographic surgery —The lesion is shaved off in thin layers. The doctor will repeat the process until the removed layers show no signs of cancer. Mohs is used to remove:
    • Large tumors
    • Tumors in hard-to-treat places
    • Tumors of unclear shape and depth
    • Cancers that have come back
  • Cryosurgery —cancer cells are frozen with a special tool and killed. The dead tissue will fall off once it warms up. May be used to treat small cancers or those on top layers of skin. It may also be used for tissue that is at high risk of turning into cancer.

Laser Therapy

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

Radiation Therapy

Radiation can kill cancer cells and shrink tumors. It is aimed at the cancer to avoid damaging as much healthy tissue as possible.

Topical Chemotherapy

A medical gel or lotion is applied over the area. It will kill the cancer cells over time. This works best to treat skin conditions before they become cancer or cancers on the outer layer of the skin.

Immunotherapy and Targeted Therapy

These therapies use medicine to help attack cancer. Immunotherapy helps to boost the immune system. It can help your body identify and attack cancer cells. Targeted therapy is a medicine that slows or stop cancers from growing and spreading.

Prevention

To help reduce your chances of skin cancer:

  • Avoid spending too much time in the sun.
  • Avoid the sun during peak sunlight hours.
  • 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) sunscreen on skin that will be exposed to the sun. Skin should have a sun protection factor (SPF) of 30 or more.
  • Use a protective lip balm.
  • Wear sunglasses with 99% or 100% UV absorption.
  • Do not use sun lamps or tanning booths.

If you see any changes in your skin contact your doctor for a skin exam.

RESOURCES:

American Academy of Dermatology
https://www.aad.org

Skin Cancer Foundation
https://www.skincancer.org

CANADIAN RESOURCES:

Canadian Cancer Society
http://www.cancer.ca

Canadian Dermatology Association
https://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: https://www.guideline.gov/summaries/summary/48130?#Section420.

Basal and squamous cell skin cancer. American Cancer Society website. Available at: https://www.cancer.org/cancer/basal-and-squamous-cell-skin-cancer.html. Accessed March 6, 2021.

Basal cell carcinoma of the skin. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/basal-cell-carcinoma-of-the-skin. Accessed March 6, 2021.

Cutaneous squamous cell carcinoma (SCC). EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/cutaneous-squamous-cell-carcinoma. Accessed March 6, 2021.

Skin cancer treatment (PDQ)—patient version. National Cancer Institute website. Available at: https://www.cancer.gov/types/skin/patient/skin-treatment-pdq. Accessed March 6, 2021.

Sunscreen FAQs. American Academy of Dermatology website. Available at: https://www.aad.org/media/stats/prevention-and-care/sunscreen-faqs. Accessed March 6, 2021.

Last reviewed March 2021 by EBSCO Medical Review Board Monica Zangwill, MD, MPH  Last Updated: 3/9/2021