Basal cell carcinoma (BCC) is the most common form of cancer in humans; it is also the most common form of skin cancer. Its incidence rises markedly in individuals over 40 years of age. Recently, it has become more common in younger persons, probably due to increased exposure to ultraviolet light.
BCC tends to grow slowly and rarely metastasizes, but—since 85 percent of basal cell carcinomas occur on the head and neck—localized invasion and destruction of surrounding tissues (bone and brain, for example) can cause significant disability.
Causes and Risk Factors
Several risk factors for BCC have been identified, but none of them, on their own, accurately predict the chances of developing cancer at a specific site. Of course, as one’s number of risk factors increases, so does the chance of developing BCC.
Contributory factors include:
- Sun exposure: Cumulative lifetime sun exposure is probably the most significant risk factor for developing BCC. A higher number of blistering sunburns over one’s life is also predictive.
- Fair skin
- Tendency to freckle
- Smoking
- Radiotherapy and phototherapy
- Number of lifetime visits to tanning beds
- Immunosuppression: Whether due to underlying illness (AIDS, diabetes, etc) or medical intervention (kidney transplantation, for example), immunosuppression increases the risk of developing BCC.
- Male gender: Much of the difference in gender incidence may be due to differences in lifestyle. Many males are still subjected to extensive occupational sun exposure.
- Genetic predisposition: Gorlin syndrome is an autosomal dominant disorder that is characterized by the occurrence of multiple basal cell carcinomas. Like many other cancers, one’s genetic makeup may be contributory or protective.
Diagnosis
An experienced clinician can usually diagnose BCC by its appearance. However, BCC is diverse in morphology and includes nodular, cystic, superficial, sclerosing, keratotic, and ulcerating forms, so clinical examination of any suspicious lesion is imperative. Biopsy is performed when the diagnosis is uncertain or when a patient is likely to be referred for specialty evaluation or treatment.
Treatment
All modalities of treatment for basal cell carcinoma are directed toward removal or destruction of the malignancy. Some approaches are associated with lower rates of recurrence or with fewer adverse effects than others:
- Excisional surgery: Considered by many to be the treatment of choice, excision with generous margins is associated with fewer adverse effects (blistering, pain, or scarring) than methods such as cryotherapy or electrocautery. Mohs’ micrographic surgery, a specialized form of excision, produces less scarring than traditional surgery. Mohs’ is most commonly used when a cancer recurs.
- Cryotherapy: The use of a liquid gas such as nitrogen to freeze a lesion seems to be effective for at least one year. Freezing the base of a BCC following curettage (removal by scraping) also appears to be effective therapy, but the incidence of scarring is higher than with surgical excision.
- Cautery/electrodessication: Vaporizing a BCC with a specially-designed electrode is another method that appears to be beneficial and preventive of long-term recurrence. Scarring may occur, particularly with wide-based lesions.
- Photodynamic therapy: Using drugs that sensitize a tumor to specific wavelengths of light seems effective and produces a better cosmetic result than cryotherapy, but patients may become extremely sensitive to light for a period of time. More than one course of therapy may be necessary for optimal results.
Basal cell carcinoma is a common malignancy; it is usually amenable to treatment when approached in a timely manner. The rise of BCC in younger populations serves as a reminder that lifestyle remains a key element in the evolution of this largely preventable disease.
Stephen Allen Christensen - Dr. Steve Christensen's writing has appeared in magazines, professional journals, poetry anthologies, and children's books since 1976.
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