• UV light exposure. Believed to be the major risk factor for most skin cancer.
• Having light-colored skin. Anyone can get skin cancer, but people with light-colored skin have a much higher risk than people with naturally darker skin color. This is because the skin pigment melanin has a protective effect in people with darker skin.
• Being older. This is probably because of the buildup of sun exposure over time.
• Being male.
• Previous skin cancer.
• Exposure to certain chemicals. Being exposed to large amounts of arsenic increases the risk of developing skin cancer.
• Radiation exposure. People who have had radiation treatment have a higher risk of developing skin cancer in the area that received the treatment.
• Xeroderma pigmentosum (XP). This very rare inherited condition reduces the ability of skin cells to repair DNA damage caused by sun exposure.
• Long-term or severe skin inflammation or injury. Scars from severe burns, areas of skin over serious bone infections and skin damaged by some severe inflammatory skin diseases are more likely to develop skin cancers, although this risk is generally small.

• Psoriasis treatment. Psoralens and ultraviolet light (PUVA) treatments given to some patients with psoriasis (a chronic inflammatory skin disease) can increase the risk of developing squamous cell skin cancer and probably other skin cancers.
• Basal cell nevus syndrome, nevoid basal cell carcinoma syndrome or Gorlin syndrome. In this rare congenital condition, people develop many basal cell cancers over their lifetime. People with this syndrome may also have abnormalities of the jaw and other bones, eyes and nervous tissue.
• Weakened immune system. People with weakened immune systems from certain diseases or medical treatments are more likely to develop many types of skin cancer. For example, people who get organ transplants are usually given medicines that weaken their immune system to help prevent their body from rejecting the new organ, which increases their risk of developing skin cancer.
• Human papillomavirus (HPV) infection. Some HPV types, especially those that affect the genital and anal areas and the skin around the fingernails, seem to be related to skin cancers in these areas.
• Smoking. Smokers are more likely to develop squamous cell skin cancer, especially on the lips. Smoking is not a known risk factor for basal cell cancer.

Biopsy. Removes all or part of the abnormal-looking skin growth for viewing under a microscope by an expert skin pathologist to check for signs of cancer.

CT scan (computed tomography). Uses a type of X-ray to create highly detailed and accurate cross-sectional images of the body.

Dermoscopy. Uses a drop of mineral oil on the lesion to reduce light reflection, make the skin more translucent, and to assist in viewing skin lesions to accurately distinguish between suspicious moles and other pigmented lesions.

Epiluminescence microscopy. Allows viewing of a lesion down to the dermo-epidermal junction—the areas where melanomas usually develop—that isn’t visible to the naked eye.

Excisional biopsy. Uses a scalpel to remove the entire growth.

Punch biopsy. Uses a special instrument called a punch to remove a circle of tissue from the abnormal-looking growth.

Skin examination. Uses a visual check of the skin for bumps or spots that look abnormal in color, size, shape or texture.

Surgery
There are a few different types we can use:

• Excision. Cutting out the tumor, along with a small margin of normal skin.
• Curettage and electrodesiccation. Useful in treating small, thin squamous cell cancers.
• Mohs surgery. Useful for squamous cell cancers that pose a higher risk for coming back, such as tumors larger than 2 cm (about 4/5 inch) across or with poorly defined edges, cancers that have come back after other treatments, cancers that are spreading along nerves under the skin and cancers on certain areas of the face or genital area.

Cryotherapy. Used for some early squamous cell cancers, especially in people who can’t have surgery.

Lymph node dissection. Might be recommended for some squamous cell cancers that are very large or have grown deeply into the skin, as well as if the lymph nodes feel enlarged and/or hard.

Radiation therapy or radiotherapy. X-rays and other types of medical radiation aimed at specific parts of the body. The radiation kills cancer cells, prevents cancer cells from developing or recurring, and improves many of cancer’s symptoms. For certain cancers, radiation therapy is combined with chemotherapy and called chemo-radiotherapy.

Systemic chemotherapy and/or targeted therapy. Chemotherapy and targeted therapy drugs (EGFR inhibitors) might be other options for patients with squamous cell cancer that has spread to lymph nodes or distant organs. These types of treatment might be combined or used separately.

Immunotherapy. Uses your own immune system to fight cancer.

Photodynamic therapy. Treatment that uses a certain type of laser light and a drug sensitive to that light to kill cancer cells. To treat skin cancer, laser light is shined onto the skin to activate the drug. Photodynamic therapy causes little damage to healthy tissue.