What is skin cancer?

Cancer develops when cells grow out of control. Skin cancer is the most frequently diagnosed type of cancer. Basal and squamous cell skin cancers are most common and are usually treatable. Melanoma is less common but more likely to spread and become life-threatening.

Who gets skin cancer?

Estimates suggest that more than 3 million people are diagnosed with skin cancer each year, about 80 percent of which are basal cell cancers, according to the American Cancer Society. Basal and squamous cell skin cancers can usually be successfully treated but cause about 2,000 deaths annually.

About 87,000 people get melanoma and about 9,700 people die from it annually. Melanoma is more common in men than in women and the risk increases with age. White people are about 20 times more likely than African Americans to develop melanoma, but people with dark skin can get it as well.

What are the risk factors for skin cancer?

The primary risk factor for skin cancer is exposure to ultraviolet (UV) radiation from the sun or tanning beds. People who spend a lot of time outdoors and individuals with pale skin that sunburns easily have the greatest risk. Avoiding the sun, wearing clothes that cover the skin and using sunscreen can reduce the likelihood of getting skin cancer.

Other risk factors for melanoma include a family history and having many moles. Smoking is a risk factor for squamous cell skin cancer, especially on the lips. Certain types of human papillomavirus (HPV) appear to trigger some skin cancers.

Individuals with a weakened immune system, such as people with HIV and organ transplant recipients, have a higher risk of skin cancer, including melanoma. They may develop Merkel cell cancer (cancer of neuroendocrine cells in the skin) or Kaposi sarcoma, a cancer of the lining of blood and lymph vessels that can occur anywhere in the body but often appears as skin lesions.

What are the symptoms of skin cancer?

Unusual changes in the skin may be a sign of skin cancer. These may include: 

  • Pale or yellow flat patches that resemble scars
  • Red, scaly or itchy patches
  • Pink or red shiny (or “pearly”) bumps
  • Open sores with oozing or crusted areas
  • Sores that don’t heal or keeping coming back
  • Wartlike growths. 

New or changing moles may be a sign of melanoma and should be reported to your doctor. Check for moles that have these characteristics: 

  • A: asymmetrical moles
  • B: moles with irregular or ragged borders
  • C: moles that contain different colors
  • D: moles that are more than a quarter inch in diameter
  • E: moles that are evolving or changing in size, shape or appearance

How is skin cancer diagnosed?

Early detection and treatment of skin cancer, especially melanoma, increases the likelihood of long-term survival. Regular visual examination of the skin can help you find abnormalities that might be cancer, and doctors can often distinguish benign moles from those that are cancerous.

The process of diagnosis starts with a physical exam and medical history, including family history and how long symptoms have been present. The doctor will examine suspicious areas of the skin and may feel for enlarged lymph nodes. You may be referred to a dermatologist for further examination. A tissue sample (a biopsy) may be removed to examine in a laboratory, or small abnormalities may be removed completely.

If melanoma is suspected, X-ray, computed tomography (CT), positron emission tomography (PET), MRI or ultrasound scans may be done to see how much the cancer has spread. Melanoma is sometimes found in other parts of the body, including the brain, after a skin abnormality has disappeared, and in rare cases it can first develop in an internal organ.

How is skin cancer treated?

Treatment for skin cancer depends on what type of cancer it is, how advanced it is when it is detected and whether it has spread to nearby lymph nodes or other parts of the body.

Surgery: Some small and localized skin cancers can be surgically removed. Depending on how large and deep the tumor is, it may be possible to remove it at a doctor’s office.

Radiation: Radiation may be used to kill cancer cells that remain after surgery or to shrink tumors that cannot be surgically removed. It is often used in conjunction with other forms of treatment.

Chemotherapy: Traditional chemotherapy works by killing fast-growing cells, including cancer cells. It can also destroy rapidly dividing healthy cells, such as those in the gut or hair follicles, leading to side effects like nausea and hair loss. Basal cell skin cancer seldom requires systemic chemotherapy.

Targeted therapy: Targeted drugs work against cancers with specific characteristics. For example, they may interfere with signaling pathways that regulate cell growth. Targeted treatment is often better tolerated than chemotherapy, but cancer may develop resistance over time.

Immunotherapy: The newest type of treatment helps the immune system fight cancer. For example, some tumors can turn off immune responses against them, and drugs known as checkpoint inhibitors can restore T cells’ ability to recognize and destroy those cancer cells. Some immunotherapies are approved for advanced melanoma, but these drugs work for only a subset of patients, and it is hard to predict who will benefit.

For more information about cancer, please visit our sister site Cancer Health.

Last Reviewed: November 9, 2017