What’s new in research and treatment of basal and squamous cell skin cancers?
Research into the causes, prevention, and treatment of basal and squamous cell 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 learning how ultraviolet (UV) light damages the DNA inside normal skin cells, and how this might cause them to become cancerous. Researchers are working to apply this new information to strategies for preventing and treating skin cancers.
Most skin cancers can be prevented. The best way to reduce the number of skin cancers and the pain and loss of life from this disease is to educate the public about skin cancer risk factors, prevention, and detection. It’s important for health care professionals and skin cancer survivors to remind others about the dangers of too much UV exposure (both from the sun and from man-made sources such as tanning beds) and about how easily they can protect their skin from UV radiation.
Skin cancer can often be detected early, when it is most likely to be cured. Monthly skin self-exams and awareness of the warning signs of skin cancer may be helpful in finding most skin cancer when they are at an early, curable stage.
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 website are listed in “Additional resources for basal and squamous cell skin cancers”.
Along with recommending staying in the shade, the American Cancer Society uses a slogan popularized in Australia as part of its skin cancer prevention message in the United States. “Slip! Slop! Slap!®… and Wrap” is a catchy way to remember when going outdoors to slip on a shirt, slop on sunscreen, slap on a hat, and wrap on sunglasses to protect your eyes and the sensitive skin around them.
Preventing genital skin cancers
Squamous cell cancers that start in the genital region account for almost half of the deaths from this type of skin cancer. Many of these cancers are 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 such as wearing condoms 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 related to HPV, including some squamous cell skin cancers.
Chemoprevention is the use of drugs to reduce cancer risk. This is likely to be more useful for people at high risk of skin cancers, such as those with certain congenital conditions (basal cell nevus syndrome, xeroderma pigmentosum, etc.), a history of skin cancer, or those who have received organ transplants, rather than for people at average risk of skin cancer.
Some of 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 they can have side effects, including possibly causing 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 drugs are being looked at to reduce the risk of basal cell skin cancers in people at high risk. Targeted drugs called hedgehog pathway inhibitors, which affect the activity of genes such as PTCH and SMO, may help some people with basal cell nevus syndrome. The drug vismodegib (Erivedge), taken daily as a capsule, has been shown to lower the number of new basal cell cancers and shrink existing tumors in people with this syndrome. The drug does have some side effects, including taste loss and muscle cramps, which can make it hard for some people to take every day. Further research on this and similar drugs is under way.
Current local treatments such as surgery and radiation therapy work well for most basal and squamous cell 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 new topical drugs, photodynamic therapy, and laser surgery may help reduce scarring and other possible side effects of treatment. The best way to use these treatments is now being studied.
Treating advanced disease
Most basal and squamous cell skin cancers are found and treated at an early stage, when they are likely to be cured, but some can 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), gefitinib (Iressa), and cetuximab (Erbitux) 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’s very rare for basal cell cancers to reach an advanced stage, but when they do, these cancers can be hard to treat. Vismodegib and sonidegib, drugs that target the hedgehog signaling pathway in cells, may help some people (see “Targeted therapy for basal and squamous cell skin cancers”). Other drugs that target this pathway are now being studied as well.
Last Medical Review: 04/02/2015
Last Revised: 07/24/2015