Basal Cell Carcinoma

Basal Cell Carcinoma

Basal Cell Carcinoma (BCC) is the most common form of skin cancer, arising from the basal cells, which are found in the deepest layer of the epidermis. It is a slow-growing cancer that rarely metastasizes or spreads to other parts of the body, but it can cause significant local damage if not treated.

Epidemiology

BCC is the most frequently occurring form of all cancers. It is estimated that over 4 million cases are diagnosed in the United States each year. The incidence of BCC is increasing worldwide, likely due to increased sun exposure and the aging population.

Risk Factors

Several risk factors are associated with the development of BCC:

• Ultraviolet (UV) exposure: Chronic exposure to UV radiation from the sun or tanning beds is the most significant risk factor.
• Skin type: Individuals with fair skin, light hair, and light eyes are at higher risk.
• Age: BCC is more common in older adults, though it can occur at any age.
• Genetic predisposition: Conditions such as Gorlin syndrome (nevoid basal cell carcinoma syndrome) increase risk.
• Immunosuppression: Patients with weakened immune systems, such as organ transplant recipients, are at higher risk.

Pathophysiology

BCC originates from the basal cells in the epidermis. These cells undergo mutations, often due to UV-induced DNA damage, leading to uncontrolled growth. The most common genetic alteration in BCC is the mutation of the PTCH1 gene, a part of the Hedgehog signaling pathway.

Clinical Features

BCC typically presents as a pearly or waxy bump on sun-exposed areas of the skin, such as the face, ears, neck, scalp, shoulders, and back. Other presentations include:

• A flat, scaly, reddish patch with a raised edge.
• A white, waxy scar-like lesion.
• A bleeding or oozing sore that does not heal.

Diagnosis

Diagnosis of BCC is primarily clinical, supported by dermatoscopic examination. A skin biopsy is performed to confirm the diagnosis and to differentiate BCC from other skin lesions such as squamous cell carcinoma or melanoma.

Treatment

The treatment of BCC depends on the size, depth, and location of the tumor, as well as patient factors. Common treatment options include:

• Surgical excision: The most common and effective treatment, involving removal of the tumor with a margin of healthy tissue.
• Mohs micrographic surgery: A precise surgical technique used for high-risk or recurrent BCCs, especially on the face.
• Curettage and electrodessication: Suitable for superficial BCCs.
• Radiation therapy: An option for patients who cannot undergo surgery.
• Topical treatments: Such as imiquimod or 5-fluorouracil for superficial BCCs.
• Targeted therapy: Vismodegib or sonidegib for advanced BCCs that are not amenable to surgery or radiation.

Prognosis

The prognosis for BCC is excellent, especially when detected early. The risk of metastasis is extremely low, but untreated BCC can cause significant local destruction and disfigurement. Patients with a history of BCC are at increased risk for developing additional skin cancers and should have regular skin examinations.

Prevention

Preventive measures include:

• Limiting sun exposure, especially during peak hours.
• Using broad-spectrum sunscreen with an SPF of 30 or higher.
• Wearing protective clothing, hats, and sunglasses.
• Avoiding tanning beds.
• Regular skin checks by a healthcare professional.

See Also

• Squamous cell carcinoma
• Melanoma
• Skin cancer

External Links

• American Cancer Society: Basal Cell Carcinoma
• American Academy of Dermatology: Basal Cell Carcinoma