Basal cell carcinoma is the most common type of skin cancer and the most common
cancer in humans. Approximately 70-80% of all cases of NMSC are BCCa and annually,
approximately 200 in every 100,000 people will develop BCCa. The majority of
BCCa’s develop in sun exposed areas such as the head and neck. These lesions
are usually slow growing and rarely spread to other areas of the body. However,
these tumors may invade locally into surrounding tissues causing a significant
amount of tissue destruction. Therefore, these tumors must be treated when found.
Sqaumous cell carcinoma:
Squamous cell carcinoma is less common than BCCa and accounts for approximately
20% of all cases of NMSC. As with BCCa, this cancer is associated with sun exposure
and lesions are commonly found on the head, neck, arms and legs. Squamous cell
carcinoma may also develop in areas of chronic inflammation or scars, such as
ulcers and burns. Squamous cell carcinoma is more likely than BCCa to spread
to other areas of the body. This occurs 2-3% of the time.
Risk factors for the development of BCCa and SCCa:
Skin type: People who are of white racial background are
more likely to develop NMSC.
Sun exposure: The major risk factor for the development
of NMSC is exposure to ultraviolet radiation in the form of sunlight.
Chronic scars: Squamous cell carcinoma of the skin may
be found in association with chronic inflammatory wounds or scars.
Gender: Non-melanoma skin cancer is more common in men,
likely due to greater sun exposure. The male to female ratio is 3:1.
Immunosuppression: Patients who are immunosuppressed are
more likely to develop NMSC. These cancers are seen with increased frequency
in patients who have undergone organ transplantation, especially SCCa, and
often these cancers are more aggressive in these patients.
Genetic predisposition: Several inherited genetic disorders
are associated with a high rate of NMSC. These include xeroderma pigmentosum,
nevoid basal cell syndrome, and albinism.