Basal-cell carcinoma
Basal-cell carcinoma (BCC), also known as basal-cell cancer, is the most common type of skin cancer. It often appears as a painless raised area of skin, which may be shiny with small blood vessels running over it; or it may present as a raised area with ulceration. Basal-cell cancer grows slowly and can damage the tissue around it but is unlikely to spread to distant areas or to result in death.
Risk factors include exposure to ultraviolet light, having lighter skin, radiation therapy, long-term exposure to arsenic, and poor immune-system function. Exposure to UV light during childhood is particularly harmful. Tanning beds have become another common source of ultraviolet radiation. Diagnosis often depends on skin examination, confirmed by tissue biopsy.
It remains unclear whether sunscreen affects the risk of basal-cell cancer. Treatment is typically by surgical removal. This can be by simple excision if the cancer is small; otherwise Mohs surgery is generally recommended. Other options may include application of cold, topical chemotherapy, laser surgery, or the use of imiquimod. In the rare cases in which distant spread has occurred, chemotherapy or targeted therapy may be used.
Basal-cell cancer accounts for at least 32% of all cancers globally. Of skin cancers other than melanoma, about 80% are basal-cell cancers. In the United States, about 35% of white males and 25% of white females are affected by BCC at some point in their lives.
Individuals with a basal-cell carcinoma typically present with a shiny, pearly skin nodule. However, superficial basal-cell cancer can present as a red patch similar to eczema. Infiltrative or morpheaform basal-cell cancers can present as a skin thickening or scar tissue – making diagnosis difficult without using tactile sensation and a skin biopsy. It is often difficult to visually distinguish basal-cell cancer from acne scar, actinic elastosis, and recent cryodestruction inflammation.
About two thirds of basal-cell carcinomas occur on sun-exposed areas of the body. One-third occur on areas of the body that are not exposed to sunlight, emphasizing the genetic susceptibility of basal-cell cancer.
Hepatitis C
Fatty changes to the liver occur in about half of those infected and are usually present before cirrhosis develops. Usually (80% of the time) this change affects less than a third of the liver. Worldwide hepatitis C is the cause of 27% of cirrhosis cases and 25% of hepatocellular carcinoma. About 10–30% of those infected develop cirrhosis over 30 years. Cirrhosis is more common in those also infected with hepatitis B, schistosoma, or HIV, in alcoholics and in those of male gender. In those with hepatitis C, excess alcohol increases the risk of developing cirrhosis 100-fold. Those who develop cirrhosis have a 20-fold greater risk of hepatocellular carcinoma. This transformation occurs at a rate of 1–3% per year. Being infected with hepatitis B in addition to hepatitis C increases this risk further.