Research into the causes, prevention, and treatment of non-melanoma skin cancer is under way in many medical centers throughout the world.
Basic skin cancer research
Scientists have made a great deal of progress in recent years in understanding how ultraviolet (UV) light damages DNA, and how this causes normal skin cells to become cancerous. Researchers are always working to apply this new information to strategies for preventing and treating skin cancers.
Public education
Most cases of skin cancer can be prevented. The best way to reduce the number of skin cancer cases and the pain and loss of life from this disease is to educate the public about skin cancer risk factors, prevention, and detection. It is important for health care professionals and skin cancer survivors to remind others about the dangers of excess UV exposure (from the sun and from man-made sources such as tanning beds) and about how easily they can protect their skin from UV radiation.
The American Academy of Dermatology (AAD) sponsors annual free skin cancer screenings throughout the country. Many local American Cancer Society offices work closely with AAD to provide volunteers for registration, coordination, and education efforts related to these free screenings. Look for information in your area about these screenings or call the American Academy of Dermatology for more information. Their phone number and Web address are listed in the “Additional resources” section of this document.
Preventing genital skin cancers
Squamous cell cancers that start in the genital region account for almost half of the deaths from keratinocyte cancers. Many of these cancers may be related to infection with certain types of human papilloma virus (HPV), which can be spread through sexual contact. Limiting the number of sexual partners a person has and using safer sex practices may therefore help lower the risk of some of these cancers.
In recent years, vaccines have been developed to help protect against infection from some types of HPV. The main intent of the vaccines has been to reduce the risk of cervical cancer, but they may also lower the risk of other cancers that might be related to HPV, including some squamous cell cancers.
Chemoprevention
An area of active research is the field of chemoprevention (using drugs to reduce cancer risk). Chemoprevention is likely to be more useful for people at high risk of skin cancers, such as those with certain congenital conditions (such as basal cell nevus syndrome), a history of skin cancer, or those who have received organ transplants, rather than for people at average risk of skin cancer.
The most widely studied drugs so far are the retinoids, which are drugs related to vitamin A. They have shown some promise in reducing the risk of squamous cell cancers but can have side effects, including the potential to cause birth defects. For this reason they are not widely used at this time, except in some people at very high risk. Further studies of retinoids are under way.
Other compounds are being looked at to reduce the risk of basal cell skin cancers in people at high risk. Drugs called hedgehog pathway inhibitors, which restore the activity of the damaged PTCH gene, may help some people with basal cell nevus syndrome. In early studies, a drug known as vismodegib (GDC-0449), taken daily as a pill, significantly lowered the number of new basal cell cancers and shrank existing tumors in people with this syndrome. The drug does have some side effects, including taste loss and muscle cramps, which might make it hard for some people to take every day. Further research on this and similar drugs is under way.
Treatment
Local treatments
Current local treatments are successful for the vast majority of non-melanoma skin cancers. Still, even some small cancers can be hard to treat if they're in certain areas. Newer forms of non-surgical treatment such as imiquimod cream, photodynamic therapy, immune response modifiers, and laser surgery may help reduce scarring and other possible side effects of treatment. Studies are now under way to determine the best way to use these treatments, and to try to improve on their effectiveness.
Treating advanced disease
Most skin cancers are found and treated at a fairly early stage, but some may spread to other parts of the body. These cancers can often be hard to treat with current therapies such as radiation and chemotherapy.
Several studies are testing newer targeted drugs for advanced squamous cell cancers. Cells from these cancers often have too much of a protein called EGFR on their surfaces, which may help them grow. Drugs that target this protein, such as erlotinib (Tarceva) and gefitinib (Iressa), are now being tested in clinical trials. A drug that targets different cell proteins, known as dasatinib (Sprycel), is also being studied for advanced skin cancers.
It is very rare for basal cell cancers to reach an advanced stage, but when they do, these cancers can be hard to treat. Most basal cell cancers have mutations (abnormal changes) in genes involved in a cell pathway called Hedgehog. The Hedgehog pathway is important in many cells and is crucial for development of the embryo and fetus. Vismodegib (Erivedge™, GDC-0449), is a new drug that targets that pathway.
This drug has been studied in patients with basal cell cancers that had spread or had come back after surgery and other local treatments. Vismodegib was given as a pill, taken once a day, and helped shrink tumors in about a third of the patients. Most side effects were mild, such as muscle spasms and joint pain, hair loss, fatigue, problems with taste, poor appetite and weight loss, diarrhea, nausea and vomiting, and constipation. Vismodegib can also cause women to stop having their periods for a time (called amenorrhea)..
Because the Hedgehog pathway is involved in fetal development, this drug can cause fetal harm if taken by a pregnant woman. It is not known if it could harm the fetus if it is taken by a male partner. This drug should not be taken by anyone pregnant or trying to become pregnant, and anyone on this drug should use reliable birth control during and after treatment
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