Types of Cancer : Lung Cancer

Definition

Lung cancer is the leading cause of cancer deaths in the United States, among both men and women. It claims more lives each year than colon, prostate, lymph and breast cancers combined.

Yet most lung cancer deaths could be prevented. That's because smoking accounts for nearly 90 percent of lung cancer cases. Your risk of lung cancer increases with the length of time and number of cigarettes you smoke. If you quit smoking, even after smoking for many years, you can significantly reduce your chances of developing lung cancer. Protecting yourself from other risk factors for lung cancer, such as exposure to asbestos, radon and secondhand smoke, also decreases your risk.

Symptoms

Lung cancer typically doesn't cause signs and symptoms in its earliest stages. Signs and symptoms of lung cancer typically occur only when the disease is advanced. Signs and symptoms of lung cancer may include:

• A new cough that doesn't go away
• Changes in a chronic cough or "smoker's cough"
• Coughing up blood, even a small amount
• Shortness of breath
• Chest pain
• Wheezing
• Hoarseness

Causes

Lung cancer most commonly begins in the cells that line your lungs. Smoking causes the majority of lung cancers — both in smokers and in people exposed to secondhand smoke. But lung cancer also occurs in people who never smoked. In these cases, there may be no clear cause of lung cancer. Doctors have identified factors that may increase the risk.

How smoking causes lung cancer
Doctors believe smoking causes lung cancer by damaging the cells that line the lungs. When you inhale cigarette smoke, which is full of cancer-causing substances (carcinogens), changes in the lung tissue begin almost immediately. At first your body may be able to repair this damage. But with each repeated exposure, normal cells that line your lungs are increasingly damaged. Over time, the damage causes cells to act abnormally and eventually cancer may develop.

Your lungs are full of blood vessels and lymph vessels, giving lung cancer cells easy access to travel to other parts of your body. For this reason, lung cancer may spread to other parts of your body before you experience any signs or symptoms. In many cases, lung cancer may spread before it can even be detected in the lungs.

Types of lung cancer
Doctors divide lung cancer into two major types based on the appearance of lung cancer cells under the microscope. Your doctor makes treatment decisions based on which major type of lung cancer you have. The two general types of lung cancer include:

• Small cell lung cancer. Small cell lung cancer, sometimes called oat cell carcinoma, occurs almost exclusively in heavy smokers and is less common than non-small cell lung cancer.
• Non-small cell lung cancer. Non-small cell lung cancer is an umbrella term for several types of lung cancers that behave in a similar way. Non-small cell lung cancers include squamous cell carcinoma, adenocarcinoma and large cell carcinoma.

Risk factors

A number of factors may increase your risk of lung cancer. Some risk factors can be controlled, for instance, by quitting smoking. And other factors can't be controlled, such as your sex. Risk factors for lung cancer include:

• Smoking. Smoking remains the greatest risk factor for lung cancer. Your risk of lung cancer increases with the number of cigarettes you smoke each day and the number of years you have smoked. Quitting at any age can significantly lower your risk of developing lung cancer.
• Your sex. Current or former women smokers have a greater risk of lung cancer than do men who have smoked an equal amount. Though it isn't known why, some experts speculate that women have a greater susceptibility to the cancer-causing substances found in tobacco. Others believe that estrogen may play a role. Women also are known to inhale more than men do, and they are less likely to quit.
• Exposure to secondhand smoke. Even if you don't smoke, your risk of lung cancer increases if you're exposed to secondhand smoke.
• Exposure to radon gas. Radon is produced by the natural breakdown of uranium in soil, rock and water that eventually becomes part of the air you breathe. Although unsafe levels of radon can accumulate in any building, the greatest exposure risk most people face is at home. Radon testing can determine whether levels are safe.
• Exposure to asbestos and other chemicals. Workplace exposure to asbestos and other substances known to cause cancer — such as arsenic, chromium, nickel and tar soot — also can increase your risk of developing lung cancer, especially if you're a smoker.
• Family history of lung cancer. People with a parent, sibling or other first-degree relative with lung cancer have an increased risk of the disease.
• Excessive alcohol use. Drinking more than a moderate amount of alcohol — no more than one drink a day for women or two drinks a day for men — may increase your risk of lung cancer.

Tests and diagnosis

Screening
Doctors aren't sure whether you should undergo screening for lung cancer. Even if you have an increased risk of lung cancer — for instance, if you're a smoker — it isn't clear that a chest X-ray or computerized tomography (CT) scan can be beneficial. Some studies show that these tests can find cancer earlier, when it may be treated more successfully. But other studies find that these tests often reveal more benign conditions that require invasive testing and expose people to unnecessary risks.

Screening for lung cancer is controversial among doctors. Studies are ongoing to determine what types of tests may be helpful and who would benefit from lung cancer screening. In the mean time, talk with your doctor if you're concerned about your risk of lung cancer. Together you can determine strategies to reduce your risk and decide whether screening tests are appropriate for you.

Diagnosis
If there's reason to think that you may have lung cancer, your doctor can order a number of tests to look for cancerous cells and to rule out other conditions. In order to diagnose lung cancer, your doctor may recommend:

• Imaging tests. An X-ray image of your lungs may reveal an abnormal mass or nodule. A CT scan can reveal small lesions in your lungs.
• Sputum cytology. If you have a cough and are producing sputum, looking at the sputum under the microscope can sometimes reveal the presence of lung cancer cells. Before the test, you may be asked to breathe a mildly irritating mist to help you produce more sputum.
• Tissue samples (biopsy). A sample of abnormal cells may be removed in a procedure called a biopsy in order to diagnose lung cancer. Your doctor can perform a biopsy in a number of ways, including bronchoscopy, in which your doctor examines abnormal areas of your lungs using a lighted tube that is passed down your throat and into your lungs; mediastinoscopy, in which an incision is made at the base of your neck and surgical tools are inserted behind your breastbone to take tissue samples; and needle biopsy, in which your doctor uses X-ray or CT images to guide a needle through your chest and into a suspicious lump or nodule to collect cells. A biopsy sample may also be taken from lymph nodes or other areas where cancer has spread, such as your liver.

Staging
Once your lung cancer has been diagnosed, your doctor will work to determine the extent, or stage, of your cancer. Your cancer's stage helps your doctor decide what treatment is most appropriate. Staging tests may include imaging procedures that allow your doctor to look for signs that cancer has spread beyond your lungs, such as magnetic resonance imaging (MRI), positron emission testing (PET) and bone scans. Not every test is appropriate for every person, so talk with your doctor about which procedures are appropriate for you.

Stages of non-small cell lung cancer

• Stage I. Cancer at this stage has invaded the underlying lung tissue but hasn't spread to the lymph nodes.
• Stage II. This stage cancer has spread to neighboring lymph nodes or invaded the chest wall.
• Stage IIIA. At this stage, cancer has spread from the lung to lymph nodes in the center of the chest.
• Stage IIIB. The cancer has spread locally to areas such as the heart, blood vessels, trachea and esophagus — all within the chest — or to lymph nodes in the area of the collarbone or to the tissue that surrounds the lungs within the rib cage (pleura).
• Stage IV. The cancer has spread to other parts of the body, such as the liver, bones or brain.

Stages of small cell lung cancer

• Limited. Cancer is confined to one lung and to its neighboring lymph nodes.
• Extensive. Cancer has spread beyond one lung and nearby lymph nodes, and may have invaded both lungs, more remote lymph nodes or other organs.

Complications

Lung cancer can cause complications, such as:

• Fluid in the chest (pleural effusion). Lung cancer can cause fluid to accumulate in the space that surrounds the lungs in the chest cavity (pleural space). Pleural effusion can result from cancer spreading outside the lungs or in reaction to lung cancer inside the lungs. Fluid accumulating in the chest can cause shortness of breath. Treatments are available to drain the fluid from your chest and reduce the risk that pleural effusion will occur again. Cancer that spreads to the pleura is considered inoperable, so surgery isn't an option for treatment.
• Cancer that spreads to other parts of the body (metastasis). Lung cancer often spreads (metastasizes) to other parts of the body — most commonly the opposite lung, brain, bones, liver and adrenal glands. Cancer that spreads can cause signs and symptoms, including pain, nausea, headaches or others based on what organ is affected. In some cases, treatments are available for isolated metastasis, but in most cases, the goal of treatment for metastasis is only to relieve signs and symptoms.
• Death. Unfortunately, survival rates haven't improved for people diagnosed with lung cancer. In most cases, the disease is fatal. Almost 60 percent, or three out of every five people, diagnosed with lung cancer die within a year. Keep in mind, however, that this number includes people diagnosed with all types of lung cancer at all stages of the disease. People diagnosed at the earliest stages have the greatest chances for a cure. Your doctor can discuss more relevant statistics about your chances for survival with you.

Treatments and drugs

You and your doctor choose a cancer treatment regimen based on a number of factors, such as your overall health, the type and stage of your cancer, and your own preferences. Treatment options typically include one or more treatments, including surgery, chemotherapy, radiation therapy or targeted drug therapy.

In some cases you may choose not to undergo treatment. For instance, you may feel that the side effects of treatment will outweigh the potential benefits. When that's the case, your doctor may suggest comfort (palliative) care to treat only the symptoms the cancer is causing, such as pain.

Treatment options for non-small cell lung cancers
Stage	Common options
I	Surgery
II	Surgery, chemotherapy, radiation
IIIA	Combined chemotherapy and radiation, sometimes surgery based on results of treatment
IIIB	Chemotherapy, sometimes radiation
IV	Chemotherapy, targeted drug therapy, clinical trials, supportive care

Treatment options for small cell lung cancers
Stage	Common options
Limited	Combined chemotherapy and radiation, sometimes surgery
Extensive	Chemotherapy, clinical trials, supportive care

Surgery
During surgery your surgeon works to remove the lung cancer and a margin of healthy tissue. Procedures to remove lung cancer include:

• Wedge resection to remove a small section of lung that contains the tumor along with a margin of healthy tissue
• Lobectomy to remove the entire lobe of one lung
• Pneumonectomy to remove an entire lung

If you undergo surgery, your surgeon may also remove lymph nodes from your chest in order to check them for signs of cancer. If your lymph nodes contain cancer cells, this usually indicates that cancer has spread, even if cancer hasn't been detected outside of your chest.

Lung cancer surgery carries risks, including bleeding and infection. Expect to feel short of breath after lung surgery. Your lung tissue will expand over time and make it easier to breathe. You may also feel pain in the muscles of your chest and in your arm on the side where you had the operation. Your doctor may recommend physical therapy or a rehabilitation program to help you restore your strength and range of motion.

Chemotherapy
Chemotherapy uses drugs to kill cancer cells. One or more chemotherapy drugs may be administered through a vein in your arm (intravenously) or taken orally. A combination of drugs usually is given in a series of treatments over a period of weeks or months, with breaks in between so that your body can recover.

Chemotherapy can be used as a first line treatment for lung cancer or as additional treatment after surgery. In some cases, chemotherapy can be used to lessen side effects of your cancer.

Radiation therapy
Radiation therapy uses high-powered energy beams, such as X-rays, to kill cancer cells. Radiation therapy can be directed at your lung cancer from outside your body (external beam radiation) or it can be put inside needles, seeds or catheters and placed inside your body near the cancer (brachytherapy).

Radiation therapy can be used alone or along with other lung cancer treatments. Sometimes it's administered at the same time as chemotherapy. Radiation therapy can also be used to lessen side effects of lung cancer.

Targeted drug therapy
Targeted therapies are newer cancer treatments that work by targeting specific abnormalities in cancer cells. Targeted therapy options for treating lung cancer include:

• Bevacizumab (Avastin). Bevacizumab stops a tumor from creating a new blood supply. Blood vessels that connect to tumors can supply oxygen and nutrients to the tumor, allowing it to grow. Bevacizumab is usually used in combination with chemotherapy and is approved for advanced and recurrent non-small cell lung cancer. Bevacizumab carries a risk of severe bleeding.
• Erlotinib (Tarceva). Erlotinib blocks chemicals that signal the cancer cells to grow and divide. Erlotinib is approved for people with advanced and recurrent non-small cell lung cancer that haven't been helped by chemotherapy. Erlotinib side effects include a skin rash and diarrhea.

Clinical trials
Clinical trials are studies of new lung cancer treatment methods. You may be interested in enrolling in a clinical trial if lung cancer treatments aren't working or if your treatment options are limited. The treatments studied in a clinical trial may be the latest innovations, but they don't guarantee a cure. Carefully weigh your treatment options with your doctor. Your participation in a clinical trial may help doctors better understand how to treat lung cancer in the future.

Supportive (palliative) care
When treatments offer little chance for a cure, your doctor may recommend you avoid harsh treatments and opt for supportive care instead. If you're receiving supportive care, your doctor may treat any signs and symptoms you experience to make you feel more comfortable, but you won't receive treatment aimed at stopping your cancer. Supportive care allows you to make the most of your final weeks or months without enduring treatment side effects that can negatively impact your quality of life.

Prevention

There's no sure way to prevent lung cancer, but you can reduce your risk if you:

• Don't smoke. If you've never smoked, don't start. Talk to your children about not smoking, so they can understand how to avoid this major risk factor for lung cancer. Many current smokers began smoking in their teens. Begin conversations about the dangers of smoking with your children early, so they know how to react to peer pressure.
• Stop smoking. Stop smoking now. Quitting reduces your risk of lung cancer, even if you've smoked for years. Talk to your doctor about strategies and stop-smoking aids that can help you quit. Options include nicotine replacement products, medications and support groups.
• Avoid secondhand smoke. If you live or work with a smoker, urge him or her to quit. At the very least, ask him or her to smoke outside. Avoid areas where people smoke, such as bars and restaurants, and seek out smoke-free options.
• Test your home for radon. Have the radon levels in your home checked, especially if you live in an area where radon is known to be a problem. High radon levels can be remedied to make your home safer. For information on radon testing, contact your local department of public health or a local chapter of the American Lung Association.
• Avoid carcinogens at work. Take precautions to protect yourself from exposure to toxic chemicals at work. In the United States, your employer must tell you if you're exposed to dangerous chemicals in your workplace. Follow your employer's precautions. For instance, if you're given a face mask for protection, always wear it. Ask your doctor what more you can do to protect yourself at work. Your risk of lung damage from these carcinogens increases if you smoke.
• Eat a diet full of fruits and vegetables. Choose a healthy diet with a variety of fruits and vegetables. Food sources of vitamins and nutrients are best. Avoid taking large doses of vitamins in pill form, as there may be unknown harms. For instance, researchers hoping to reduce the risk of lung cancer in heavy smokers gave them beta carotene supplements. Results showed the supplements actually increased the risk of cancer in smokers.
• Drink alcohol in moderation, if at all. Limit yourself to one drink a day if you're a woman or two drinks a day if you're a man. Anyone age 65 and older should drink no more than one drink a day.
• Exercise. Aim to achieve at least 30 minutes of exercise on most days of the week. Check with your doctor first if you aren't already exercising regularly. Start out slowly and continue adding more activity. Biking, swimming and walking are good choices. Add exercise throughout your day — park farther away from work and walk the rest of the way or take the stairs rather than the elevator.

Types of Cancer : Skin Cancer

Definition

Skin cancer — the abnormal growth of skin cells — most often develops on skin exposed to the sun. But this common form of cancer can also occur on areas of your skin not ordinarily exposed to sunlight.

There are three major types of skin cancer — basal cell carcinoma, squamous cell carcinoma and melanoma, which is the most serious of skin cancer.

All three types of skin cancer are on the rise — but most skin cancers can be prevented by limiting or avoiding exposure to ultraviolet (UV) radiation and by paying attention to suspicious changes in your skin. And with early detection, you can receive successful treatment for most skin cancers, even the most aggressive forms.

Symptoms

Skin cancer develops primarily on areas of sun-exposed skin, including the scalp, face, lips, ears, neck, chest, arms and hands, and on the legs in women. But it can also form on areas that rarely see the light of day — your palms, beneath your fingernails, the spaces between your toes or under your toenails, and your genital area.

Skin cancer affects people of all skin tones, including those with darker complexions. When melanoma occurs in those with dark skin tones, it's more likely to occur in areas not normally considered to be sun-exposed.

A cancerous skin lesion can appear suddenly or develop slowly. Its appearance depends on the type of cancer.

Basal cell carcinoma
This is the most common skin cancer. It's also the most easily treated and the least likely to spread. Basal cell carcinoma usually appears as one of the following:

• A pearly or waxy bump on your face, ears or neck
• A flat, flesh-colored or brown scar-like lesion on your chest or back

Squamous cell carcinoma
Squamous cell carcinoma is easily treated if detected early, but it's slightly more apt to spread than is basal cell carcinoma. Most often, squamous cell carcinoma appears as one of the following:

• A firm, red nodule on your face, lips, ears, neck, hands or arms
• A flat lesion with a scaly, crusted surface on your face, ears, neck, hands or arms

Melanoma
This is the most serious form of skin cancer and the one responsible for most skin cancer deaths. Melanoma can develop anywhere on your body, in otherwise normal skin or in an existing mole that turns malignant. Melanoma most often appears on the trunk, head or neck of affected men. In women, this type of cancer most often develops on the arms or legs.

Warning signs of melanoma include:

• A large brownish spot with darker speckles located anywhere on your body
• A simple mole located anywhere on your body that changes in color, size or feel or that bleeds
• A small lesion with an irregular border and red, white, blue or blue-black spots on your trunk or limbs
• Shiny, firm, dome-shaped bumps located anywhere on your body
• Dark lesions on your palms, soles, fingertips and toes, or on mucous membranes lining your mouth, nose, vagina and anus

Less common skin cancers
Other, less common types of skin cancer include:

• Kaposi sarcoma. This rare form of skin cancer develops in the skin's blood vessels and causes red or purple patches on the skin or mucous membranes. Like melanoma, it's a serious form of skin cancer. It's mainly seen in people with weakened immune systems, such as people with AIDS, and in people taking medications that suppress their natural immunity, such as people who've undergone organ transplants.
• Merkel cell carcinoma. In this rare cancer, firm, shiny nodules occur on or just beneath the skin and in hair follicles. The nodules may be red, pink or blue and can vary in size from a quarter of an inch (about 6 millimeters) to more than 2 inches (about 50 millimeters). Merkel cell carcinoma is usually found on sun-exposed areas on the head, neck, arms and legs. Unlike basal and squamous cell carcinomas, Merkel cell carcinoma grows rapidly and often spreads to other parts of the body.
• Sebaceous gland carcinoma. This uncommon and aggressive cancer originates in the oil glands in the skin. Sebaceous gland carcinomas — which usually appear as hard, painless nodules — can develop anywhere, but most occur on the eyelid, where they're frequently mistaken for benign conditions.

Precancerous skin lesions, such as an actinic keratosis, also can develop into squamous cell skin cancer. Actinic keratoses appear as rough, scaly, brown or dark-pink patches. They're most commonly found on the face, ears, lower arms and hands of fair-skinned people whose skin has been damaged by the sun.

Not all skin changes are cancerous. The only way to know for sure is to have your skin examined by your doctor or dermatologist.

Causes

Skin cancer begins in your skin's top layer — the epidermis. The epidermis is as thin as a pencil line, and it provides a protective layer of skin cells that your body continually sheds. The epidermis contains three main types of cells:

• Squamous cells lie just below the outer surface and function as the skin's inner lining.
• Basal cells, which produce new skin cells, sit beneath the squamous cells.
• Melanocytes — which produce melanin, the pigment that gives skin its normal color — are located in the lower part of your epidermis. Melanocytes produce more melanin when you're in the sun to help protect the deeper layers of your skin. Extra melanin produces the darker color of tanned skin.

Normally, skin cells within the epidermis develop in a controlled and orderly way. In general, healthy new cells push older cells toward the skin's surface, where they die and eventually are sloughed off. This process is controlled by DNA — the genetic material that contains the instructions for every chemical and biological process in your body. Skin cancer occurs when this process malfunctions. When DNA is damaged, changes occur in the instructions, which can cause new cells to grow out of control and form a mass of cancer cells.

The role of UV light
Much of the damage to DNA in skin cells results from ultraviolet (UV) radiation found in sunlight and in commercial tanning lamps and tanning beds. UV light is divided into three wavelength bands — ultraviolet A (UVA), ultraviolet B (UVB) and ultraviolet C (UVC). Only UVA and UVB rays reach the earth. UVC radiation is completely absorbed by atmospheric ozone.

At one time scientists believed that only UVB rays played a role in the formation of skin cancer. And UVB light does cause harmful changes in skin cell DNA, including the activation of oncogenes — a type of gene that, when turned on, can turn a normal cell into a malignant one. UVB rays are responsible for sunburn and for many basal cell and squamous cell cancers.

But UVA also contributes to skin cancer. It penetrates the skin more deeply than UVB does, weakens the skin's immune system and increases the risk of cancer, especially melanoma. Tanning beds deliver high doses of UVA, which makes them especially dangerous.

Other factors that may contribute to skin cancer
Sun exposure doesn't explain melanomas or other skin cancers that develop on skin not ordinarily exposed to sunlight. Heredity may play a role. Skin cancer can also develop from exposure to toxic chemicals or as a result of radiation treatments.

Risk factors

These factors may increase your risk of skin cancer:

• Fair skin. Having less pigment (melanin) in your skin provides less protection from damaging UV radiation. If you have blond or red hair, light-colored eyes, and you freckle or sunburn easily, you're much more likely to develop skin cancer than is a person with darker features.
• A history of sunburns. Every time you get sunburned, you damage your skin cells and increase your risk of developing skin cancer. After a sunburn, your body works to repair the damage. Having multiple blistering sunburns as a child or teenager increases your risk of developing skin cancer as an adult. Sunburns in adulthood also are a risk factor.
• Excessive sun exposure. Anyone who spends considerable time in the sun may develop skin cancer, especially if your skin isn't protected by sunscreen or clothing. Tanning also puts you at risk. A tan is your skin's injury response to excessive UV radiation.
• Sunny or high-altitude climates. People who live in sunny, warm climates are exposed to more sunlight than are people who live in colder climates. Living at higher elevations, where the sunlight is strongest, also exposes you to more radiation.
• Moles. People who have many moles or abnormal moles called dysplastic nevi are at increased risk of skin cancer. These abnormal moles — which look irregular and are generally larger than normal moles — are more likely than others to become cancerous. If you have a history of abnormal moles, watch them regularly for changes.
• Precancerous skin lesions. Having skin lesions known as actinic keratoses can increase your risk of developing skin cancer. These precancerous skin growths typically appear as rough, scaly patches that range in color from brown to dark pink. They're most common on the face, lower arms and hands of fair-skinned people whose skin has been sun damaged.
• A family history of skin cancer. If one of your parents or a sibling has had skin cancer, you may be at increased risk of the disease. Some families are affected by a condition called familial atypical mole-malignant melanoma (FAMMM) syndrome. The hallmarks of FAMMM include a history of melanoma in one or more close relatives and having more than 50 moles — some of which are atypical. Because people with this syndrome have an extremely high risk of developing melanoma, frequent screening for signs of skin cancer is crucial.
• A personal history of skin cancer. If you developed skin cancer once, you're at risk of developing it again. Even basal cell and squamous cell carcinomas that have been successfully removed can recur in the same spot, often within two to three years.
• A weakened immune system. People with weakened immune systems are at greater risk of developing skin cancer. This includes people living with HIV/AIDS or leukemia and those taking immunosuppressant drugs after an organ transplant.
• Fragile skin. Skin that has been burned, injured or weakened by treatments for other skin conditions is more susceptible to sun damage and skin cancer. Certain psoriasis treatments and eczema creams might increase your risk of skin cancer.
• Exposure to environmental hazards. Exposure to environmental chemicals, including some herbicides, increases your risk of skin cancer.
• Age. The risk of developing skin cancer increases with age, primarily because many skin cancers develop slowly. The damage that occurs during childhood or adolescence may not become apparent until middle age. Still, skin cancer isn't limited to older people. Basal cell and squamous cell carcinomas are increasing fastest among women younger than 40.

When to seek medical advice

you notice any suspicious change in your skin, consult your doctor right away. As with most cancers, early detection increases the chances of successful treatment. Don't wait for the area to start hurting — skin cancer seldom causes pain.

Tests and diagnosis

See your doctor if you notice a new skin growth, a bothersome change in your skin, a change in the appearance or texture of a mole, or a sore that doesn't heal in two weeks. Your doctor may suspect cancer by simply looking at your skin. But to properly diagnose skin cancer, your doctor or dermatologist will need to take a small sample of your skin (biopsy) for analysis in a lab. A biopsy can usually be done in a doctor's office using a local anesthetic.

Skin cancer is generally divided into two stages:

• Local. In this stage, cancer affects only the skin.
• Metastatic. At this point, cancer has spread beyond the skin.

Because superficial skin cancers such as basal or squamous cell carcinoma rarely spread, a biopsy often is the only test needed to determine the cancer stage. But if you have a large growth or one that's existed for some time, your doctor may do further tests to determine the extent of the cancer.

Treatments and drugs

Treatment for skin cancer and the precancerous skin lesions known as actinic keratoses varies, depending on the size, type, depth and location of the lesions. Often the abnormal cells are surgically removed or destroyed with topical medications. Most skin cancer treatments require only a local anesthetic and can be done in an outpatient setting. Sometimes no treatment is necessary beyond an initial biopsy that removes the entire growth.

If additional treatment is needed, options may include:

• Freezing. Your doctor may destroy actinic keratoses and some small, early skin cancers by freezing them with liquid nitrogen (cryosurgery). The dead tissue sloughs off when it thaws. The treatment may leave a small, white scar. You may need a repeat treatment to remove the growth completely.
• Excisional surgery. This type of treatment may be appropriate for any type of skin cancer. Your doctor cuts out (excises) the cancerous tissue and a surrounding margin of healthy skin. A wide excision — removing extra normal skin around the tumor — may be recommended in some cases. To minimize or avoid scarring, especially on your face, you may need to consult a doctor skilled in skin reconstruction.
• Laser therapy. A precise, intense beam of light vaporizes growths, generally with little damage to surrounding tissue and with minimal bleeding, swelling and scarring. A doctor may use this therapy to treat superficial skin cancers or precancerous growths on lips.
• Mohs surgery. This procedure is for larger, recurring or difficult-to-treat skin cancers, which may include both basal and squamous cell carcinomas. Your doctor removes the skin growth layer by layer, examining each layer under the microscope, until no abnormal cells remain. This procedure allows cancerous cells to be removed without taking an excessive amount of surrounding healthy skin. Because it requires special skill, the surgery should be done only by specially trained doctors.
• Curettage and electrodesiccation. After removing most of a growth, your doctor scrapes away layers of cancer cells using a circular blade (curet). An electric needle destroys any remaining cancer cells. This simple, quick procedure is common in treating small or thin basal cell cancers. It leaves a small, flat, white scar.
• Radiation therapy. Radiation may be used to destroy basal and squamous cell carcinomas if surgery isn't an option.
• Chemotherapy. In chemotherapy, drugs are used to kill cancer cells. For cancers limited to the top layer of skin, creams or lotions containing anti-cancer agents may be applied directly to the skin. Topical drugs can cause severe inflammation and leave scars. Systemic chemotherapy can be used to treat skin cancers that have spread to other parts of the body.

Under study
Treatments for skin cancer under study include:

• Photodynamic therapy (PDT). This treatment destroys skin cancer cells with a combination of laser light and drugs that makes cancer cells sensitive to light. Photodynamic therapy for precancerous skin lesions is currently available by prescription. If you have PDT, you will need to avoid direct sunlight for at least six weeks after treatment.
• Biological therapy (also called immunotherapy). Immunotherapy medications such as interferon and interleukin-2 are under study to treat melanoma and nonmelanoma skin cancers. These types of drugs stimulate your immune system to fight cancer. Other medications applied to your skin, such as imiquimod (Aldara), enhance your immune reaction to skin cancer.

Prevention

Most skin cancers are preventable. To protect yourself, follow these skin cancer prevention tips:

• Avoid the sun between 10 a.m. and 4 p.m. Because the sun's rays are strongest during this period, try to schedule outdoor activities for other times of the day, even in winter or when the sky is cloudy. You absorb UV radiation year-round, and clouds offer little protection from damaging rays. Remember, sunburns and suntans cause skin damage that can increase your risk of developing skin cancer. Sun exposure accumulated over time also may cause skin cancer.

• Wear sunscreen year-round. Sunscreens don't filter out all harmful UV radiation, especially the radiation that can lead to melanoma. But they play a major role in an overall sun protection program. Sunscreens that contain ingredients such as titanium dioxide and mexoryl do a better job at blocking UVA rays. Choose a broad-spectrum sunscreen that has a sun protection factor (SPF) of at least 15. Use a generous amount of sunscreen on all exposed skin, including your lips, the tips of your ears, and the backs of your hands and neck.

  For the most protection, apply sunscreen 20 to 30 minutes before sun exposure and reapply it every two hours throughout the day, as well as after swimming or exercising. Apply sunscreen to young children before they go outdoors, and teach older children and teens how to use sunscreen to protect themselves. Keep sunscreen in your car as well as with your gardening tools, and sports and camping gear.

• Wear protective clothing. Sunscreens don't provide complete protection from UV rays. That's why it's a good idea to also wear dark, tightly woven clothing that covers your arms and legs, and a broad-brimmed hat, which provides more protection than a baseball cap or visor does. Some companies also sell photoprotective clothing. A dermatologist can recommend an appropriate brand. Don't forget sunglasses. Look for those that block both UVA and UVB rays.
• Avoid tanning beds and tan-accelerating agents. Tanning beds emit UVA rays, which may be as dangerous as UVB rays — especially since UVA light penetrates deeper into your skin and causes precancerous skin lesions.
• Be aware of sun-sensitizing medications. Some common prescription and over-the-counter drugs — including antibiotics; certain cholesterol, high blood pressure and diabetes medications; birth control pills; nonsteroidal anti-inflammatory drugs such as ibuprofen (Advil, Motrin, others); and the acne medicine isotretinoin (Accutane) — can make your skin more sensitive to sunlight. Ask your doctor or pharmacist about the side effects of any medications you take. If they increase your sensitivity to sunlight, be sure to take extra precautions.
• Check your skin regularly and report changes to your doctor. Examine your skin often for new skin growths or changes in existing moles, freckles, bumps and birthmarks. With the help of mirrors, check your face, neck, ears and scalp. Examine your chest and trunk, and the tops and undersides of your arms and hands. Examine both the front and back of your legs, and your feet, including the soles and the spaces between your toes. Also check your genital area, and between your buttocks.
• Have regular skin exams. Consult your doctor for a complete skin exam every year if you're older than 40, or more often if you're at high risk of developing skin cancer.

Self-examination: A guide
To detect melanomas or other skin cancers, use the A-B-C-D-E skin self-examination guide, adapted from the American Academy of Dermatology:

• A is for asymmetrical shape. Look for moles with irregular shapes, such as two very different-looking halves.
• B is for irregular border. Look for moles with irregular, notched or scalloped borders — the characteristics of melanomas.
• C is for changes in color. Look for growths that have many colors or an uneven distribution of color.
• D is for diameter. Look for growths that are larger than about 1/4 inch (about 6 millimeters).
• E is for evolving. Look for changes over time, such as a mole that grows in size or that changes color or shape. Moles may also evolve to develop new signs and symptoms, such as new itchiness or bleeding.