A Dermatologist's Guide to Skin Cancer

Skin cancer is the most common form of cancer in the United States. According to The Skin Cancer Foundation, every year more than two million people in the U.S. are diagnosed with skin cancer. In fact, one out of five Americans will develop skin cancer in their lifetime.

Even though skin cancer is common, many people do not fully understand the disease. This article provides a simple overview of skin cancer and provides some tips for prevention and early detection.

What Is Skin Cancer?

In simple terms, skin cancer is the growth of abnormal skin cells. If left untreated, these abnormal, cancerous cells can grow or spread throughout the body causing scarring, deformity, function loss and even death.

There are two main categories of skin cancer: non-melanoma skin cancer (basal cell carcinoma and squamous cell carcinoma) and melanoma.

Non-melanoma skin cancer: Basal cell carcinoma and Squamous cell carcinoma

The most common forms of skin cancer are basal cell carcinoma and squamous cell carcinoma. These cancers are almost always found on parts of the body that are most frequently exposed to the sun, including the head and the neck. The risk of these cancers is strongly related to the amount of exposure to the sun that a person has had over their lifetime.

These forms of skin cancer are less likely to spread (metastasize) to other parts of the body than melanomas. Thus, they are also less likely to become life-threatening. However, early detection and treatment are still important. If they are not treated, they have the potential to grow into nearby tissues and organs, potentially causing scarring, deformity and loss of function in the part of the body it has invaded. In certain advanced cases, untreated non-melanoma skin cancer (usually squamous cell carcinoma) may metastasize, and be fatal.


Melanoma skin cancers can appear anywhere on the body, but are most common in particular locations. The chest and back are the most common sites in men; in women, the most common site is the legs. The face and neck are common sites in both sexes.

Though less common than non-melanoma skin cancers, melanomas are more serious. If caught in its earliest stages, it can be successfully treated. However, if not detected and addressed early, melanoma is likely to spread to other areas of the body at which point it can be extremely difficult to treat effectively.

What Causes Skin Cancer?

The primary cause of skin cancer is exposure to ultraviolet (UV) radiation from the sun or from tanning beds (artificial UV rays). However, there are other contributing factors including:

  • Smoking
  • Environmental carcinogens
  • General aging and light skin color
  • HPV infections
  • Genetics
  • The extended use of immunosuppressive medications

Skin Cancer Prevention

The best way to prevent skin cancer is to limit any unnecessary exposure to UV radiation. This includes avoiding indoor tanning, minimizing exposure to the sun when UV rays are at their highest, and using sunscreen. Avoiding tobacco use and taking vitamin supplements has also been shown to aid in prevention. If a skin lesion is changing in size or pigmentation, is bleeding or will not heal, you should have it examined by a dermatologist. Lastly, it is advisable to have a yearly skin cancer screening by your dermatologist as early detection and diagnosis makes treatment easier and more effective.


If you are diagnosed with skin cancer there are many different treatment options available. The best course of treatment depends on the type and location of cancer, your age, and whether or not the cancer is primary or a recurrence. Treatment options may include:

  • Cryotherapy: Liquid nitrogen is used to freeze pre-cancerous lesions at the cellular level, destroying the tissue.
    • Surgical Excision: A technique where the physician surgically removes the tumor along with a margin of healthy skin surrounding the tumor to ensure that all cancer cells are removed.
    • Mohs Surgery (Mohs’ micrographic surgery): A surgical procedure where cancerous tissue is removed and the surrounding margin is progressively examined in layers (or stages) until only cancer free tissue remains.
    • Topical Chemotherapy: Cancer treatment drugs are applied to the area via a lotion or cream.
    • Radiation Therapy: Ionized radiation is used to damage the DNA of the cancerous tissue causing cellular death.
    • Full Chemotherapy: This may be necessary in cases where the cancer has metastasized (spread to other areas of the body).

Dr. Peggy Chern is a board certified Dermatologist currently practicing at Westlake Dermatology. Dr. Chern specializes in surgical and procedural dermatology including Mohs surgery, vein, laser, and cosmetic procedures.

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