Skin cancer is a common, usually lowgrade cancerous (malignant) growth of the skin. It starts from cells that begin as normal skin cells and transform into those with the potential to reproduce in an outofcontrol manner. Unlike other cancers, the vast majority of skin cancers have no potential to spread to other parts of the body (metastasize) and become lifethreatening.
There are two major types of skin cancer: basal cell carcinoma (the most common) and squamous cell carcinoma (the second most common). Melanoma is also a form of skin cancer but is far less common, though more dangerous, than the other two varieties.
The most common risk factors for skin cancer are as follows.
Basal and squamous cell cancers
Basal and squamous cell skin cancers are by far the most common cancers of the skin. Both are found mainly on parts of the body exposed to the sun, such as the head and neck. These cancers are strongly related to a person’s sun exposure.
Basal and squamous cell cancers are much less likely than melanomas to spread to other parts of the body and become life threatening. Still, it’s important to find and treat them early. If left alone, they can grow larger and invade nearby tissues and organs, causing scarring, deformity, or even loss of function in some parts of the body. Some of these cancers (especially squamous cell cancers) can spread if not treated, and in some cases they can even be fatal.
Melanomas are cancers that develop from melanocytes, the cells that make the brown pigment that gives skin its color. Melanocytes can also form benign (noncancerous) growths called moles. (Your doctor might call the mole anevus.)
Melanomas can occur anywhere on the body, but are more likely to start in certain areas. The trunk (chest and back) is the most common place in men. In women, the legs are the most common site. The neck and face are other common places for melanoma to start.
Melanomas are not as common as basal cell and squamous cell skin cancers, but they can be far more serious. Like basal cell and squamous cell cancers, melanoma is almost always curable in its early stages. But if left alone, melanoma is much more likely to spread to other parts of the body, where it can be very hard to treat.
Other skin cancers
There are many other types of skin cancers as well, but they are much less common:
Together, these types account for less than 1% of all skin cancers.
It’s important for doctors to tell the types of skin cancer apart, because they are treated differently. It’s also important for you to know what skin cancers look like. This can help you find them at the earliest possible stage, when they are cured most easily.
Once the type of melanoma has been established, the next step is to classify the disease as to its degree of severity.
Classifications for melanomas are called stages. The stage refers to the thickness, depth of penetration, and the degree to which the melanoma has spread. The staging is used to determine treatment.
Early melanomas (Stages 0 and I) are localized; Stage 0 tumors are in situ, meaning that they are noninvasive and have not penetrated below the surface of the skin, while Stage I tumors have invaded the skin but are small, nonulcerated, and are growing at a slow mitotic rate. Stage II tumors, though localized, are larger (generally over 1 mm. thick) and/or may be ulcerated or have a mitotic rate of greater than than 1/mm2; they are considered intermediate melanomas. More advanced melanomas (Stages III and IV) have spread (metastasized) to other parts of the body. There are also subdivisions within stages.
Anyone can get skin cancer, regardless of skin color. It is estimated that one in five Americans will develop skin cancer in their lifetime. When caught early, skin cancer is highly treatable. You can detect skin cancer early by following these tips for checking your skin.
Squamous cell carcinomas detected at an early stage and removed promptly are almost always curable and cause minimal damage. However, left untreated, they eventually penetrate the underlying tissues and can become disfiguring. A small percentage even metastasize to local lymph nodes, distant tissues, and organs and can become fatal. Therefore, any suspicious growth should be seen by a physician without delay. A tissue sample (biopsy) will be examined under a microscope to arrive at a diagnosis. If tumor cells are present, treatment is required.
Fortunately, there are several effective ways to eradicate squamous cell carcinoma. The choice of treatment is based on the tumor’s type, size, location, and depth of penetration, as well as the patient’s age and general health.
Treatment can almost always be performed on an outpatient basis in a physician’s office or at a clinic. A local anesthetic is used during most surgical procedures. Pain or discomfort is usually minimal, and there is rarely much pain afterwards.
Using a scalpel or curette (a sharp, ringshaped instrument), a physician trained in Mohs surgery removes the visible tumor with a very thin layer of tissue around it. While the patient waits, this layer is sectioned, frozen, stained and mapped in detail, then checked under a microscope thoroughly. If cancer is still present in the depths or peripheries of this excised surrounding tissue, the procedure is repeated on the corresponding area of the body still containing tumor cells until the last layer viewed under the microscope is cancerfree. Mohs surgery spares the greatest amount of healthy tissue, reduces the rate of local recurrence, and has the highest overall cure rate — about 9499 percent — of any treatment for SCC. It is often used on tumors that have recurred, are poorly demarcated, or are in hardtotreat, critical areas around the eyes, nose, lips, ears, neck, hands and feet. After tumor removal,, the wound may be allowed to heal naturally or may be reconstructed immediately; the cosmetic outcome is usually excellent.
he physician uses a scalpel to remove the entire growth, along with a surrounding border of apparently normal skin as a safety margin. The wound around the surgical site is then closed with sutures (stitches). The excised tissue specimen is then sent to the laboratory for microscopic examination to verify that all cancerous cells have been removed. A repeat excision may be necessary on a subsequent occasion if evidence of skin cancer is found in the specimen. The accepted cure rate for primary tumors with this technique is about 92 percent. This rate drops to 77 percent for recurrent squamous cell carcinomas.
This technique is usually reserved for small lesions. The growth is scraped off with a curette (an instrument with a sharp, ringshaped tip), and burning heat produced by an electrocautery needle destroys residual tumor and controls bleeding. This procedure is typically repeated a few times, a deeper layer of tissue being scraped and burned each time to help ensure that no tumor cells remain. It can produce cure rates approaching those of surgical excision for superficially invasive squamous cell carcinomas without highrisk characteristics. However, it is not recommended for any invasive or aggressive SCCs, those in highrisk or difficult sites, such as the eyelids, genitalia, lips and ears, or other sites that would be left with cosmetically undesirable results, since the procedure leaves a sizable, hypopigmented scar.
The physician destroys the tumor tissue by freezing it with liquid nitrogen, using a cottontipped applicator or spray device. There is no cutting or bleeding, and no anesthesia is required. The procedure may be repeated several times at the same session to help ensure destruction of all malignant cells. The growth becomes crusted and scabbed, and usually falls off within weeks. Redness, swelling, blistering and crusting can occur following treatment, and in darkskinned patients, some pigment may be lost. Inexpensive and easy to administer, cryosurgery may be the treatment of choice for patients with bleeding disorders or intolerance to anesthesia. However, it has a lower overall cure rate than the surgical methods. Depending on the physician’s expertise, the 5year cure rate can be quite high with selected, generally superficial squamous cell carcinoma; but cryosurgery is not often used today for invasive SCC because deeper portions of the tumor may be missed and because scar tissue at the cryotherapy site might obscure a recurrence.
Xray beams are directed at the tumor, with no need for cutting or anesthesia. Destruction of the tumor usually requires a series of treatments, administered several times a week for one to four weeks, or sometimes daily for one month. Cure rates range widely, from about 85 to 95 percent, since the technique does not provide precise control in identifying and removing residual cancer cells at the margins of the tumor. The technique can involve longterm cosmetic problems and radiation risks, as well as multiple visits. For these reasons, though this therapy limits damage to adjacent tissue, it is mainly used for tumors that are hard to treat surgically, as well as patients for whom surgery is not advised, such as the elderly or those in poor health.
PDT can be especially useful for growths on the face and scalp. A chemical agent that reacts to light, such as topical 5aminolevulinic acid (5ALA) or methyl aminolevulinate (MAL), is applied to the growths at the physician’s office; it is taken up by the abnormal cells. Hours later, those medicated areas are activated by a strong light. The treatment selectively destroys squamous cell carcinomas while causing minimal damage to surrounding normal tissue. However, the treatment is not yet FDAapproved for squamous cell carcinoma, and while it may be effective with early, noninvasive tumors (e.g., Bowen’s disease), overall recurrence rates vary considerably (from 0 to 52 percent), so the technique is not currently recommended for invasive SCC. Redness and swelling are common side effects. After treatment, patients become locally photosensitive for 48 hours where the lightsensitizing agent was applied, and must avoid both outdoor and indoor light and be careful to use sun protection.
This therapy is not yet FDAapproved for SCC, though it can be used for superficial lesions, with recurrence rates similar to those of PDT. The skin’s outer layer and variable amounts of deeper skin are removed using a carbon dioxide or erbium YAG laser. This method is bloodless, and gives the physician good control over the depth of tissue removed. It actually seals blood vessels as it cuts, making it useful for patients with bleeding disorders, and it is also sometimes used when other treatments have failed. But the risks of scarring and pigment loss are slightly greater than with other techniques.
5fluorouracil (5FU) and imiquimod, both FDAapproved for treatment of actinic keratoses and superficial basal cell carcinomas, are also being tested for the treatment of some superficial squamous cell carcinomas. Successful treatment of Bowen’s disease, a noninvasive SCC, has been reported. However, invasive SCC should not be treated with 5FU. Some trials have shown that imiquimod may be effective with certain invasive SCCs, but it is not yet FDAapproved for this purpose. Imiquimod stimulates the immune system to produce interferon, a chemical that attacks cancerous and precancerous cells, while 5FU is a topical form of chemotherapy that has a direct toxic effect on cancerous cells.
Because most treatment options involve cutting, some scarring from the tumor removal should be expected. This is most often cosmetically acceptable with small cancers, but removal of a larger tumor often requires reconstructive surgery, involving a skin graft or flap to cover the defect. Mohs surgeons are trained in reconstructive surgery, so visit to a plastic surgeon is usually unnecessary.
The three most common types of skin cancer are basal cell carcinoma, squamous cell carcinoma (both are often grouped in nonmelanoma skin cancers) and melanoma.
Because skin cancers are caused by the uncontrolled growth of skin cells, the first presentation is usually a visible change in a person’s skin. Consult a trained physician immediately if you observe any of these warning signs associated with common skin cancers:
Nonmelanoma skin cancers are some of the most treatable cancers. When melanoma is caught and treated early (before it spreads to the lymph nodes), it is also highly curable. The goal of treatment for skin cancer is to remove, or excise, all of the cancer. Typically, the first line therapies are surgical. Nonsurgical treatments may be an option in some cases.
The type of surgical treatment used depends on the type, size, depth and location of the tumor. In most cases, the procedure is done on an outpatient basis. The most common surgical procedures to remove cancerous areas of the skin are:
Radiation or chemotherapy may be necessary for advanced cases of skin cancer or when patients are unable to have surgery.
The incidence of skin cancer has been increasing quickly for the past few years. One in two men and one in three women will develop nonmelanoma skin cancer in their lifetime. Once a patient has a nonmelanoma skin cancer, there is a much higher risk of developing more skin cancers.
The risks factors for developing nonmelanoma skin cancer include: fair skin, indoor tanning bed use, multiple blistering sunburns, heavy UV exposure, prior skin cancer diagnosis, northern European ancestry, history of radiation therapy, immunosuppression, exposure to arsenic, and some forms of the HPV virus. Individuals at higher risk of melanoma include those with: red or blonde hair, blue or green eyes, many atypical moles, a firstdegree relative with a history of melanoma, a previous diagnosis of melanoma or nonmelanoma skin cancer(s).
Sun exposure can damage your skin during any season, but summer rays are more harmful and can raise the risk of developing skin cancer. Smart sun care tips include: