Basal Cell Carcinoma
Basal cell carcinoma (BCC) is the most common type of skin cancer, originating from the basal cell layer of the skin appendages.
- Rarely metastasizes but is locally invasive and capable of local tissue destruction and disfigurement
Most common cancer in Europe, Australia, and the United States; the most common type of skin cancer
- Over 2 million new cases each year in the United States; 2.5 times more common than squamous cell carcinoma (SCC)
- Highest incidence in the world is in Australia.
- White individuals have a 1 in 5 chance of developing BCC during their lifetime.
- Most common skin cancer in Asian and Hispanic individuals; second most common skin cancer in African American/black individuals (1)
- Predominant age: generally >60 years
- Predominant sex: male > female (2:1 ratio)
Not well established
Etiology and Pathophysiology
UV radiation induces inflammation and cyclooxygenase activation in the skin.
Several genetic conditions increase the risk of developing BCC:
- Albinism (recessive alleles)
- Xeroderma pigmentosum (autosomal recessive)
- Bazex-Dupré-Christol syndrome (rare, X-linked dominant)
- Nevoid BCC syndrome/Gorlin syndrome (rare, autosomal dominant)
- Cytochrome P450 CYP2D6 and glutathione S-transferase detoxifying enzyme gene mutations (especially in truncal BCC, marked by clusters of BCCs and a younger age of onset)
- Mutations in the tumor suppressor gene patched, or activated mutations in smoothened, resulting in upregulation of hedgehog pathway signaling
- Chronic sun exposure (UV radiation); increased susceptibility in the following phenotypes:
- Light complexion: skin type I (burns, but does not tan) and skin type II (usually burns, sometimes tans)
- Red or blond hair
- Blue or green eyes
- Tendency to sunburn
- Male sex, although increasing risk in women due to lifestyle changes, such as tanning beds
- Previous history of nonmelanoma skin cancer
- Family history of skin cancer
- Chronic immunosuppression: transplant recipients (5 to 10 times higher incidence), patients with HIV (2 times higher incidence), or lymphomas
- Arsenic exposure
- UV radiation and/or use of tanning devices
- Xeroderma pigmentosum
- Use broad-spectrum sunscreens of at least SPF 30 daily at least 15 minutes before outdoor activity. Reapply every 2 hours, or immediately after swimming or sweating.
- Avoid overexposure to the sun. Avoid tanning beds.
- The USPSTF concludes the current evidence is insufficient to assess the balance of benefits and harms of visual skin examination by a clinician to screen for skin cancer in adults. The American Cancer Society recommends cancer-related checkups every 3 years in patients 20 to 39 years old and yearly in patients ≥40 years
Commonly Associated Conditions
- Cosmetic disfigurement (head and neck most often affected)
- Loss of vision with orbital involvement
- Loss of nerve function due to perineural spread or extensive and deep invasion
- Ulcerating neoplasms are prone to infections.
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