Basal Cell Carcinoma at a Glance
- Most common cancer in humans.
- Caused by exposure to ultraviolet light; associated with PTCH gene mutation in many cases.
- Incidence increasing in younger populations.
- Locally destructive.
- Treated by surgical excision, electrodesiccation and curettage, Mohs micrographic surgery, and occasionally irradiation.
BCC is the most common cancer in humans. It is estimated that over 1 million new cases occur each year in the United States. The malignancy accounts for approximately 75% of all nonmelanoma skin cancers (NMSC) and almost 25% of all cancers diagnosed in the United States.1 Epidemiological data indicate that the overall incidence is increasing worldwide significantly by 3%–10% per year.2
BCC is more common in elderly individuals but is becoming increasingly frequent in people younger than 50 years of age. Christenson et al noted a disproportionate increase in BCC in women under age 40.3 Men are affected slightly more often than are women. Levi et al reported that the incidence of BCC rose steadily in the Swiss Canton of Vaud between 1976 and 1998 to levels of 75.1 in 100,000 in males and 66.1 in 100,000 in females.4,5 Stang et al in Westphalia, Germany found that the incidence rate of BCC during a 5-year period (1998–2003) was 63.6 in men and 54.0 in women.6 A study of NMSC in Aruba supported these findings.7 In that study, BCC was the most common type of skin cancer diagnosed between 1980 and 1995. Tumors were more frequent in patients older than 60 years of age, and 57% were in men. The highest percentage of lesions occurred on the nose (20.9%), followed by other sites on the face (17.7%).7 Incidence in Europe was examined by the recent study in Croatia. From 2003 to 2005, the crude incidence rate for the Croatian population of 100,000 was 54.9 for men and 53.9 for women. The vast majority of BCCs were located on the head and neck.8
BCC character develops on sun-exposed skin of lighter skinned individuals. Incidence rates of BCC in Asians living in Singapore increased from 1968 to 2006, especially among the older, more fairly complected Chinese patents. Skin cancer trends in Asians from 1968–2006 showed BCC rates increased the most among persons older than 60 years.9
BCC is rare in dark skin because of the inherent photoprotection of melanin and melanosomal dispersion. An estimated 1.8% of BCCs occur in blacks, and BCC is approximately 19 times more common in whites than blacks.10
Risk factors for BCC have been well characterized and include ultraviolet light (UVL) exposure, light hair and eye color, northern European ancestry, and inability to tan.1 An Italian study indicated the important role of sunburns, and therefore intense sun exposure, rather than that of prolonged sun exposure to increase the risk of BCC.11
The pathogenesis of BCC involves exposure ...