Skin cancer
Cancer occurs when normal cells undergo a transformation during which they grow and multiply without normal controls.
- As the cells multiply, they form a mass called a tumor. Tumors of the skin are often referred to as lesions.
- Tumors are cancerous only if they are malignant. This means that they encroach on and invade neighboring tissues because of their uncontrolled growth.
- Tumors may also travel to remote organs via the bloodstream or lymphatic system.
- This process of invading and spreading to other organs is called metastasis.
- Tumors overwhelm surrounding tissues by invading their space and taking the oxygen and nutrients they need to survive and function.
The vast majority of skin cancers are BCCs or SCCs. While malignant, these are unlikely to spread to other parts of the body. They may be locally disfiguring if not treated early.
- A small but significant number of skin cancers are malignant melanomas. It is a highly aggressive cancer that tends to spread to other parts of the body. These cancers may be fatal if not treated early.
- Actinic keratosis is a patch of red or brown, scaly, rough skin, which can develop into squamous cell carcinoma.
- Some abnormal moles are developed into melanoma over time.
- Most people have 10-40 moles on their body.
- Moles can be flat or raised; some begin as flat and become raised over time.
- The surface is usually smooth.
- Moles are round or oval and no larger than ¼-inch across.
- Moles are usually pink, tan, brown, or the same color as the skin. Other colors are sometimes noted.
- An individual's moles usually look pretty much alike. A mole that looks different from the others should be examined by your health-care provider.
- People with dysplastic nevi often have a lot of them, perhaps as many as 100 or more.
- People with many dysplastic nevi are more likely to develop melanoma, either within an existing nevus or on an area of normal skin.
- Dysplastic nevi are usually irregular in shape, with notched or fading borders.
- Dysplastic nevi may be flat or rose, and the surface may be smooth or rough ("pebbly").
- Dysplastic nevi are often large, ¼-inch across or even larger.
- Dysplastic nevi are typically of mixed color, including pink, red, tan, and brown.
[FONT="]Basal cell carcinoma:[/FONT][FONT="] [/FONT][FONT="]Light-colored skin, sun exposure, and age are all important factors in the development of basal cell carcinomas. People who have fair skin and are older have higher rates of basal cell carcinoma. About 20% of these skin cancers, however, occur in areas that are not sun-exposed, such as the chest, back, arms, legs, and scalp. The face, however, remains the most common location for basal cell lesions. Weakening of the immune system, whether by disease or medication, can also promote the risk of developing basal cell carcinoma. Other risk factors include[/FONT]
- Exposure to sun. There is evidence that, in contrast to squamous cell carcinoma, basal cell carcinoma is promoted not by accumulated sun exposure but by intermittent sun exposure like that received during vacations, especially early in life. According to the U.S. National Institutes of Health, ultraviolet (UV) radiation from the sun is the main cause of skin cancer. The risk of developing skin cancer is also affected by where a person lives. People who live in areas that receive high levels of UV radiation from the sun are more likely to develop skin cancer. In the United States, for example, skin cancer is more common in Texas than it is in Minnesota, where the sun is not as strong. Worldwide, the highest rates of skin cancer are found in South Africa and Australia, which are areas that receive high amounts of UV radiation.
- Age. Most skin cancers appear after age 50, but the sun's damaging effects begin at an early age. Therefore, protection should start in childhood in order to prevent skin cancer later in life.
- Exposure to ultraviolet radiation in tanning booths. Tanning booths are very popular, especially among adolescents, and they even let people who live in cold climates radiate their skin year-round.
- Therapeutic radiation, such as that given for treating other forms of cancer.
[FONT="]Superficial basal cell carcinomas often appear on the chest or back and look more like patches of raw, dry skin. They grow slowly over the course of months or years.[/FONT]
[FONT="]Basal cell carcinomas grow slowly, taking months or even years to become sizable. Although spread to other parts of the body (metastasis) is very rare, a basal cell carcinoma can damage and disfigure the eye, ear, or nose if it grows nearby.[/FONT]
[FONT="]Diagnosis: [/FONT][FONT="]To make a proper diagnosis, doctors usually remove all or part of the growth by performing a biopsy. This usually involves taking a sample by injecting a local anesthesia and scraping a small piece of skin. This method is referred to as a shave biopsy. The skin that is removed is then examined under a microscope to check for cancer cells.[/FONT]
[FONT="]Treatment: [/FONT][FONT="]There are many ways to successfully treat a basal cell carcinoma with a good chance of success of 90% or more. The doctor's main goal is to remove or destroy the cancer completely with as small a scar as possible. To plan the best treatment for each patient, the doctor considers the location and size of the cancer, the risk of scarring, and the person's age, general health, and medical history.[/FONT]
[FONT="]Methods used to treat basal cell carcinomas include:[/FONT]
- Curettage and desiccation: Dermatologists often prefer this method, which consists of scooping out the basal cell carcinoma by using a spoon like instrument called a curette. Desiccation is the additional application of an electric current to control bleeding and kill the remaining cancer cells. The skin heals without stitching. This technique is best suited for small cancers in non-crucial areas such as the trunk and extremities.
- Surgical excision: The tumor is cut out and stitched up.
- Radiation: Doctors often use radiation treatments for skin cancer occurring in areas that are difficult to treat with surgery. Obtaining a good cosmetic result generally involves many treatment sessions, perhaps 25 to 30.
- Cryosurgery: Some doctors trained in this technique achieve good results by freezing basal cell carcinomas. Typically, liquid nitrogen is applied to the growth to freeze and kill the abnormal cells.
- Mohs micrographic surgery: Named for its pioneer, Dr. Frederic Mohs, this technique of removing skin cancer is better termed "microscopically controlled excision." The surgeon meticulously removes a small piece of the tumor and examines it under the microscope during surgery. This sequence of cutting and microscopic examination is repeated in a painstaking fashion so that the basal cell carcinoma can be mapped and taken out without having to estimate or guess the width and depth of the lesion. This method removes as little of the healthy normal tissue as possible. Cure rate is very high, exceeding 98%. Mohs micrographic surgery is preferred for large basal cell carcinomas, those that recur after previous treatment, or lesions affecting parts of the body where experience shows that recurrence is common after treatment by other methods. Such body parts include the scalp, forehead, ears, and the corners of the nose. In cases where large amounts of tissue need to be removed, the Mohs surgeon sometimes works with a plastic (reconstructive) surgeon to achieve the best possible postsurgical appearance.
- Medical therapy using creams that attack cancer cells or stimulate the immune system. These are applied several times a week for several weeks. They produce brisk inflammation and irritation. The advantages of this method are that it avoids surgery, lets the patient perform treatment at home, and may give a better cosmetic result. Disadvantages include discomfort, which may be severe, and a lower cure rate, which makes medical treatment unsuitable for treating most skin cancers on the face.
[FONT="]Common sense preventive techniques include:[/FONT]
- limiting recreational sun exposure;
- avoiding unprotected exposure to the sun during peak radiation times (the hours surrounding noon);
- wearing broad-brimmed hats and tightly-woven protective clothing while outdoors in the sun;
- regularly using a waterproof or water resistant sunscreen with UVA protection and SPF 30 or higher;
- undergoing regular checkups and bringing any suspicious-looking or changing lesions to the attention of the doctor; and
- Avoiding the use of tanning beds and using a sunscreen with an SPF of 30 and protection against UVA (long waves of ultraviolet light.). Many people go out of their way to get an artificial tan before they leave for a sunny vacation, because they want to get a "base coat" to prevent sun damage. Even those who are capable of getting a tan, however, only get protection to the level of SPF 6, whereas the desired level is an SPF of 30. Those who only freckle get little or no protection at all from attempting to tan; they just increase sun damage. Sunscreen must be applied liberally and reapplied every two to three hours, especially after swimming or physical activity that promotes perspiration, which can weaken even sunscreens labeled as "waterproof."
[FONT="]Squamous cell carcinoma: [/FONT][FONT="][/FONT]
[FONT="]Squamous cell carcinoma is cancer that begins in the squamous cells, which are thin, flat cells that look like fish scales under the microscope. The word "squamous" came from the Latin squama, meaning "the scale of a fish or serpent" because of the appearance of the cells.[/FONT]
[FONT="]Squamous cells are found in the tissue that forms the surface of the skin, the lining of the hollow organs of the body, and the passages of the respiratory and digestive tracts. Thus, squamous cell carcinomas can actually arise in any of these tissues.[/FONT]
[FONT="]Squamous cell carcinoma of the skin occurs roughly one-quarter as often as basal cell carcinoma. Light-colored skin and a history of sun exposure are even more important in predisposing to this kind of cancer than to basal cell carcinoma. Men are affected more often than women. Patterns of dress and hairstyle may play a role. Women, whose hair generally covers their ears, develop squamous cell carcinomas far less often in this location than do men.[/FONT]
[FONT="]The earliest form of squamous cell carcinoma is called actinic (or solar) keratosis. Actinic keratoses appear as rough, red bumps on the scalp, face, ears, and backs of the hands. They often appear against a background of mottled, sun-damaged skin. They can be quite sore and tender, out of proportion to their appearance. In a patient with actinic keratoses, the rate at which one such keratosis may invade deeper in the skin to become a fully-developed squamous cell carcinoma is estimated to be in the range of 10%-20% over 10 years, though it may take less time. An actinic keratosis that becomes thicker and tenderer raises the concern that it may have transformed into an invasive squamous cell carcinoma.[/FONT]
[FONT="]A rapidly-growing form of squamous cell carcinoma that forms a mound with a central crater is called a keratoacanthoma. While some consider this not a true cancer but instead a condition that takes care of itself, most pathologists consider it to be a form of squamous cell cancer and clinicians treat is accordingly.[/FONT]
[FONT="]Other forms of squamous cell carcinoma that have not yet invaded deeper into the skin include:[/FONT]
- actinic cheilitis, involving the lower lip with redness and scale, and blurring the border between the lip and the surrounding skin;
- Bowen's disease sometimes referred to as squamous cell carcinoma in situ. (The Latin words "in situ" refer to the presence of the cancer only in the superficial epidermis, without deeper involvement.) Bowen's Disease appears as scaly patches on sin-exposed parts of the trunk and extremities; and
- Bowenoid papulosis: These are genital warts that under the microscope look like Bowen's
[FONT="]Treatment:[/FONT][FONT="][/FONT]
[FONT="]Techniques for treating squamous cell carcinoma are similar to those for basal cell carcinoma (for detailed descriptions, see above under treatment of basal cell carcinoma):[/FONT]
- Curettage and desiccation: Dermatologists often prefer this method, which consists of scooping out the basal cell carcinoma by using a spoon like instrument called a curette. Desiccation is the additional application of an electric current to control bleeding and kill the remaining cancer cells. The skin heals without stitching. This technique is best suited for small cancers in non-crucial areas such as the trunk and extremities.
- Surgical excision: The tumor is cut out and stitched up.
- Radiation: Doctors often use radiation treatments for skin cancer occurring in areas that are difficult to treat with surgery. Obtaining a good cosmetic result generally involves many treatment sessions, perhaps 25 to 30.
- Cryosurgery: Some doctors trained in this technique achieve good results by freezing basal cell carcinomas. Typically, liquid nitrogen is applied to the growth to freeze and kill the abnormal cells.
- Mohs micrographic surgery: Named for its pioneer, Dr. Frederic Mohs, this technique of removing skin cancer is better termed, "microscopically controlled excision." The surgeon meticulously removes a small piece of the tumor and examines it under the microscope during surgery. This sequence of cutting and microscopic examination is repeated in a painstaking fashion so that the basal cell carcinoma can be mapped and taken out without having to estimate or guess the width and depth of the lesion. This method removes as little of the healthy normal tissue as possible. Cure rate is very high, exceeding 98%. Mohs micrographic surgery is preferred for large basal cell carcinomas, those that recur after previous treatment, or lesions affecting parts of the body where experience shows that recurrence is common after treatment by other methods. Such body parts include the scalp, forehead, ears, and the corners of the nose. In cases where large amounts of tissue need to be removed, the Mohs surgeon sometimes works with a plastic (reconstructive) surgeon to achieve the best possible postsurgical appearance.
- Medical therapy using creams that attack cancer cells (5-Fluorouracil--5-FU, Efudex, Fluoroplex) or stimulate the immune system (Aldara). These are applied several times a week for several weeks. They produce brisk inflammation and irritation. The advantages of this method is that it avoids surgery, lets the patient perform treatment at home, and may give a better cosmetic result. Disadvantages include discomfort, which may be severe, and a lower cure rate, which makes medical treatment unsuitable for treating most skin cancers on the face.
[FONT="]Prevention: [/FONT][FONT="]Even more so than is the case with basal cell carcinoma, the key principles of prevention are minimizing sun exposure and getting regular checkups.[/FONT]
[FONT="]Common-sense preventive techniques are the same as for basal cell carcinoma and include:[/FONT]
- limiting recreational sun exposure;
- avoiding unprotected exposure to the sun during peak radiation times (the hours surrounding noon);
- wearing broad-brimmed hats and tightly-woven protective clothing while outdoors in the sun;
- regularly using a waterproof or water-resistant sunscreen with UVA protection and SPF 30 or higher;
- undergoing regular checkups and bringing any suspicious-looking or changing lesions to the attention of a doctor; and
- Avoiding the use of tanning beds and using a sunscreen with an SPF 30 and protection against UVA (long waves of ultraviolet light.). Many people go out of their way to get an artificial tan before they leave for a sunny vacation, because they want to get a "base coat" to prevent sun damage. Even those who are capable of getting a tan, however, only get protection to the level of SPF 6, whereas the desired level is an SPF of 30. Those who only freckle get little or no protection at all from attempting to tan; they just increase sun damage. Sunscreen must be applied liberally, and reapplied every two to three hours, especially after swimming or physical activity that promotes perspiration, which can weaken even sunscreens labeled as "waterproof."