8.4: Cancer
Cancer begins in your cells, which are the building blocks of your body. Normally, your body forms new cells as you need them, replacing old cells that die. Sometimes this process goes wrong. New cells grow even when you don’t need them, and old cells don’t die when they should. These extra cells can form a mass called a tumor. Tumors are abnormal growths in your body. They are made up of extra cells. Normally, old cells die, and new ones take their place. Sometimes, however, this process goes wrong. New cells form even when you don’t need them, and old cells don’t die when they should. When these extra cells form a mass, it is called a tumor.
Tumors can be either benign or malignant. Benign tumors aren’t cancer. Malignant ones are. Benign tumors grow only in one place. They cannot spread or invade other parts of your body. Even so, they can be dangerous if they press on vital organs, such as your brain. Treatment often involves surgery. Benign tumors usually don’t grow back.
Cells from malignant tumors can invade nearby tissues. They can also break away and spread to other parts of the body.
Most cancers are named for where they start. For example, lung cancer starts in the lung, and breast cancer starts in the breast. The spread of cancer from one part of the body to another is called metastasis. Symptoms and treatment depend on the cancer type and how advanced it is.
Treatments
Treatment plans may include surgery, radiation and/or chemotherapy.
Radiation is a form of energy released in particles or waves. In high doses, radiation destroys cells or keeps them from multiplying.
Radiation therapy is a cancer treatment. Its goal is to kill cancer cells and shrink tumors. Unlike cancer cells, most of your normal cells recover from radiation therapy. Doctors try to protect normal cells by limiting the radiation dosage and spreading treatment out over time. When they use radiation machines, they shield as much of your body as possible while targeting the cancer.
Normally, your cells grow and die in a controlled way. Cancer cells keep forming without control. Chemotherapy is drug therapy that can kill these cells or stop them from multiplying. However, it can also harm healthy cells, which causes side effects.
During chemotherapy you may have no side effects or just a few. The kinds of side effects you have depend on the type and dose of chemotherapy you get. Side effects vary, but common ones are nausea, vomiting, tiredness, pain and hair loss. Healthy cells usually recover after chemotherapy, so most side effects gradually go away.
Your course of therapy will depend on the cancer type, the chemotherapy drugs used, the treatment goal and how your body responds. You may get treatment every day, every week or every month. You may have breaks between treatments so that your body has a chance to build new healthy cells. You might take the drugs by mouth, in a shot or intravenously.
What Is Risk?
Do you know the four types of risk factors that affect your cancer risk? Or that your level of contact with these risk factors can affect your risk? This section explains the concept of risk and lets you test your knowledge of the subject. Go to this website to understand cancer risk factors.
Can I Lower My Risk?
Here you can explore your risk for 6 cancers: breast, cervical, colon, lung, prostate, and skin. What are the risk factors for each of these cancers? Which risk factors apply to you? And what can you do to reduce your risk?
- Breast Cancer
- Cervical Cancer
- Colorectal Cancer
- Lung Cancer
- Prostate Cancer
- Skin Cancer
Is This News Story True?
You’ve heard the stories about things like cell phones and deodorants causing cancer. How do you decide if the stories you find in the media are accurate? It is important to analyze what you read in the paper, see on television, hear on the radio, or find on the Internet. A good analysis will help you determine whether the information is likely to be accurate. Below is a list of questions to consider when you hear about new cancer research studies.
-
Who is reporting the results?
- Is the newspaper, radio or TV station, or Internet site a reliable source of medical news? You might want to talk to your health care provider to help you judge the reliability of the source.
-
Was the study based in the laboratory, on animals, or on people?
- The results of research on people are more likely to be meaningful to you.
-
How large is the study?
- In general, when it comes to understanding medical risks, the larger the study the more valid the data will be for the general population.
-
Does it include people like you?
- Check to see if some of the people in the study were the same age, sex, ethnic background, income group as yourself and had the same health concerns.
-
Are the results presented in an easy-to-understand way?
- They should use absolute risk, relative risk, or some other easy-to-understand number.
-
Does the report clearly tell what behavior or medical treatment was studied?
- Information about the study should include what behavior or medical treatment was being studied. It should also include what outcomes, such as lower cancer risk or increased detection, were measured in the study.
-
What are other possible explanations for the study results?
- Researchers should discuss other possible explanations for the results. These may include other risk factors or problems with the research.
-
Where was the research done?
- Scientists at a medical school or large hospital, for example, might be better able to conduct complex experiments or have more experience.
-
Has the study been published in a peer-reviewed journal?
- Medical journals use a peer review process to help ensure the quality of the research. (Peer review is an appraisal of research against accepted standards by professionals in the field.)
Skin Cancer
Skin cancer is the most common form of cancer in the United States. The two most common types of skin cancer—basal cell and squamous cell carcinomas—are highly curable. However, melanoma, the third most common skin cancer, is more dangerous. About 65%–90% of melanomas are caused by exposure to ultraviolet (UV) light.
Each year, more than 68,000 Americans are diagnosed with melanoma, and another 48,000 are diagnosed with an early form of the disease that involves only the top layer of skin. Also, more than 2 million people are treated for basal cell or squamous cell skin cancer each year. Basal cell skin cancer is several times more common than squamous cell skin cancer.
Skin cancers are named for the type of cells that become malignant (cancer). The three most common types are:
- Melanoma : Melanoma begins in melanocytes (pigment cells). Most melanocytes are in the skin. See the picture of a melanocyte and other skin cells. Melanoma can occur on any skin surface. In men, it’s often found on the skin on the head, on the neck, or between the shoulders and the hips. In women, it’s often found on the skin on the lower legs or between the shoulders and the hips.Melanoma is rare in people with dark skin. When it does develop in people with dark skin, it’s usually found under the fingernails, under the toenails, on the palms of the hands, or on the soles of the feet.
- Basal cell skin cancer : Basal cell skin cancer begins in the basal cell layer of the skin. It usually occurs in places that have been in the sun. For example, the face is the most common place to find basal cell skin cancer.In people with fair skin, basal cell skin cancer is the most common type of skin cancer.
- Squamous cell skin cancer : Squamous cell skin cancer begins in squamous cells. In people with dark skin, squamous cell skin cancer is the most common type of skin cancer, and it’s usually found in places that are not in the sun, such as the legs or feet.However, in people with fair skin, squamous cell skin cancer usually occurs on parts of the skin that have been in the sun, such as the head, face, ears, and neck.
Unlike moles, skin cancer can invade the normal tissue nearby. Also, skin cancer can spread throughout the body. Melanoma is more likely than other skin cancers to spread to other parts of the body. Squamous cell skin cancer sometimes spreads to other parts of the body, but basal cell skin cancer rarely does.
When skin cancer cells do spread, they break away from the original growth and enter blood vessels or lymph vessels. The cancer cells may be found in nearby lymph nodes. The cancer cells can also spread to other tissues and attach there to form new tumors that may damage those tissues. The spread of cancer is called metastasis.
Symptoms of Melanoma
Often the first sign of melanoma is a change in the shape, color, size, or feel of an existing mole. Melanoma may also appear as a new mole. Thinking of “ABCDE” can help you remember what to look for:
- Asymmetry : The shape of one half does not match the other half.
- Border that is irregular : The edges are often ragged, notched, or blurred in outline. The pigment may spread into the surrounding skin.
- Color that is uneven : Shades of black, brown, and tan may be present. Areas of white, gray, red, pink, or blue may also be seen.
- Diameter : There is a change in size, usually an increase. Melanomas can be tiny, but most are larger than the size of a pea (larger than 6 millimeters or about 1/4 inch).
- Evolving : The mole has changed over the past few weeks or months.
Melanomas can vary greatly in how they look. Many show all of the ABCDE features. However, some may show changes or abnormal areas in only one or two of the ABCDE features.
In more advanced melanoma, the texture of the mole may change. The skin on the surface may break down and look scraped. It may become hard or lumpy. The surface may ooze or bleed. Sometimes the melanoma is itchy, tender, or painful.
Visit the National Cancer Institute’s Symptoms of Melanoma webpage to view photos of an asymmetric melanoma and a dysplastic nevus.
A change on the skin is the most common sign of skin cancer. This may be a new growth, a sore that doesn’t heal, or a change in an old growth. Not all skin cancers look the same. Usually, skin cancer is not painful.
Common symptoms of basal cell or squamous cell skin cancer include:
- A lump that is small, smooth, shiny, pale, or waxy
- A lump that is firm and red
- A sore or lump that bleeds or develops a crust or a scab
- A flat red spot that is rough, dry, or scaly and may become itchy or tender
- A red or brown patch that is rough and scaly
Risk Factors
When you’re told that you have skin cancer, it’s natural to wonder what may have caused the disease. The main risk factor for skin cancer is exposure to sunlight (UV radiation), but there are also other risk factors. A risk factor is something that may increase the chance of getting a disease.
People with certain risk factors are more likely than others to develop skin cancer. Some risk factors vary for the different types of skin cancer.
Risks for Any Type of Skin Cancer
Studies have shown that the following are risk factors for the three most common types of skin cancer:
- Sunlight : Sunlight is a source of UV radiation . It’s the most important risk factor for any type of skin cancer. The sun’s rays cause skin damage that can lead to cancer.
- Severe, blistering sunburns : People who have had at least one severe, blistering sunburn are at increased risk of skin cancer. Although people who burn easily are more likely to have had sunburns as a child, sunburns during adulthood also increase the risk of skin cancer.
- Lifetime sun exposure : The total amount of sun exposure over a lifetime is a risk factor for skin cancer.
- Tanning : Although a tan slightly lowers the risk of sunburn, even people who tan well without sunburning have a higher risk of skin cancer because of more lifetime sun exposure.
Sunlight can be reflected by sand, water, snow, ice, and pavement. The sun’s rays can get through clouds, windshields, windows, and light clothing.
In the United States, skin cancer is more common where the sun is strong. For example, more people in Texas than Minnesota get skin cancer. Also, the sun is stronger at higher elevations, such as in the mountains.
Doctors encourage people to limit their exposure to sunlight.
- Sunlamps and tanning booths : Artificial sources of UV radiation, such as sunlamps and tanning booths, can cause skin damage and skin cancer. Health care providers strongly encourage people, especially young people, to avoid using sunlamps and tanning booths. The risk of skin cancer is greatly increased by using sunlamps and tanning booths before age 30.
- Personal history : People who have had melanoma have an increased risk of developing other melanomas. Also, people who have had basal cell or squamous cell skin cancer have an increased risk of developing another skin cancer of any type.
- Family history : Melanoma sometimes runs in families. Having two or more close relatives (mother, father, sister, brother, or child) who have had this disease is a risk factor for developing melanoma.
- Skin that burns easily : Having fair (pale) skin that burns in the sun easily, blue or gray eyes, red or blond hair, or many freckles increases the risk of skin cancer.
- Certain medical conditions or medicines : Medical conditions or medicines (such as some antibiotics, hormones, or antidepressants) that make your skin more sensitive to the sun increase the risk of skin cancer. Also, medical conditions or medicines that suppress the immune system increase the risk of skin cancer.
Other Risk Factors for Melanoma
The following risk factors increase the risk of melanoma:
- Dysplastic nevus : A dysplastic nevus is a type of mole that looks different from a common mole. A dysplastic nevus may be bigger than a common mole, and its color, surface, and border may be different. It’s usually wider than a pea and may be longer than a peanut. A dysplastic nevus can have a mixture of several colors, from pink to dark brown. Usually, it’s flat with a smooth, slightly scaly or pebbly surface, and it has an irregular edge that may fade into the surrounding skin. A dysplastic nevus is more likely than a common mole to turn into cancer. However, most do not change into melanoma. A doctor will remove a dysplastic nevus if it looks like it might have changed into melanoma.
- More than 50 common moles : Usually, a common mole is smaller than a pea, has an even color (pink, tan, or brown), and is round or oval with a smooth surface. Having many common moles increases the risk of developing melanoma.
Symptoms of Melanoma
Often the first sign of melanoma is a change in the shape, color, size, or feel of an existing mole. Melanoma may also appear as a new mole. Thinking of “ABCDE” can help you remember what to look for:
- Asymmetry : The shape of one half does not match the other half.
- Border that is irregular : The edges are often ragged, notched, or blurred in outline. The pigment may spread into the surrounding skin.
- Color that is uneven : Shades of black, brown, and tan may be present. Areas of white, gray, red, pink, or blue may also be seen.
- Diameter : There is a change in size, usually an increase. Melanomas can be tiny, but most are larger than the size of a pea (larger than 6 millimeters or about 1/4 inch).
- Evolving : The mole has changed over the past few weeks or months.
Melanomas can vary greatly in how they look. Many show all of the ABCDE features. However, some may show changes or abnormal areas in only one or two of the ABCDE features.
In more advanced melanoma, the texture of the mole may change. The skin on the surface may break down and look scraped. It may become hard or lumpy. The surface may ooze or bleed. Sometimes the melanoma is itchy, tender, or painful.
How To Check Your Skin
Your doctor or nurse may suggest that you do a regular skin self-exam to check for the development of a new skin cancer.
The best time to do this exam is after a shower or bath. Check your skin in a room with plenty of light. Use a full-length mirror and a hand-held mirror.
It’s best to begin by learning where your birthmarks, moles, and other marks are and their usual look and feel.
Check for anything new:
- A new mole (that looks different from your other moles)
- A new red or darker color flaky patch that may be a little raised
- A new flesh-colored firm bump
- A change in the size, shape, color, or feel of a mole
- A sore that doesn’t heal
Check yourself from head to toe:
- Look at your face, neck, ears, and scalp. You may want to use a comb or a blow dryer to move your hair so that you can see better. You also may want to have a relative or friend check through your hair. It may be hard to check your scalp by yourself.
- Look at the front and back of your body in the mirror. Then, raise your arms and look at your left and right sides.
- Bend your elbows. Look carefully at your fingernails, palms, forearms (including the undersides), and upper arms.
- Examine the back, front, and sides of your legs. Also look around your genital area and between your buttocks.
- Sit and closely examine your feet, including your toenails, your soles, and the spaces between your toes.
By checking your skin regularly, you’ll learn what is normal for you. It may be helpful to record the dates of your skin exams and to write notes about the way your skin looks. If your doctor has taken photos of your skin, you can compare your skin to the photos to help check for changes. If you find anything unusual, see your doctor.
Check out your risk of melanoma using the Melanoma Cancer Risk Assessment Tool .
This is an interactive tool that allows doctors to estimate a person’s absolute risk of developing invasive melanoma (skin cancer) over the next 5 years for people age 20 to 70 years. The tool allows doctors to identify individuals at higher risk of melanoma in order to plan appropriate screening interventions with them.
What is breast cancer?
Cancer is a disease in which cells in the body grow out of control. When cancer starts in the breast, it is called breast cancer. The breast is made up of three main parts: glands, ducts, and connective tissue. Sometimes, breast cells become abnormal and grow faster than normal cells. These extra cells form a mass called a tumor. Some tumors are “benign,” or not cancerous. Other tumors are “malignant,” meaning they are cancerous and have the ability to spread to other parts of the breast and body and disrupt normal functions in those areas.
All women are at risk for breast cancer.
Men can also get breast cancer, but this is rare. Breast cancer is the second most common cancer in women. Among Hispanic women, it is the most common cause of cancer deaths, and it is the second most common cause of cancer deaths among white, black, Asian or Pacific Islander, and American Indian or Alaska Native women. Although more white women get breast cancer, more black women die from it. Each year, approximately 190,000 women are diagnosed with breast cancer and 40,000 women die from the disease.
What puts me at greater risk?
Several factors may affect your risk of developing breast cancer, including:
- Getting older
- Not having children, or having your first child later in life
- Starting your first menstrual period at an early age
- Beginning menopause at a late age
- Having a personal history of breast cancer or certain benign breast diseases, such as atypical ductal hyperplasia
- Having close family relatives (such as a mother, sister, father, or daughter) who have had breast cancer
- Having a genetic condition, such as certain mutations in your BRCA1 or BRCA2 genes
- Having been treated with radiation therapy to the breast or chest
- Being overweight, particularly after menopause
- Using hormone replacement therapy for a long time
- Using oral contraceptives
- Drinking alcohol
- Being physically inactive
What are the symptoms?
When breast cancer starts out, it is too small to feel and does not cause signs and symptoms. As it grows, however, breast cancer can cause changes in how the breast looks or feels. Symptoms may include:
- A new lump in the breast
- A lump that has changed
- A change in the size or shape of the breast
- Pain in the breast or nipple that does not go away
- Flaky, red, or swollen skin anywhere on the breast
- A nipple that is very tender or that turns inward
- Blood or any other type of fluid coming from the nipple that is not milk when nursing a baby
These symptoms may be caused by something other than cancer, but the only way to know is to get checked.
How can I find out if I have breast cancer?
Women should begin to have routine screenings for breast cancer at the age of 50. Women under the age of 50 should talk to their health care provider about when and how often they should be screened. If you have any risk factors or symptoms of breast cancer, talk to a doctor, nurse, or health care professional.
A mammogram is the best test for finding breast cancer early. It is a series of X-ray pictures of the breast that allow doctors to look for early signs of breast cancer, sometimes up to three years before it can be felt. If your mammogram is abnormal or more tests are required, do not panic. An abnormal mammogram does not always mean you have cancer. It does mean that you will need to have some additional X-rays or other tests before your doctor can be sure. Other tests may include an ultrasound (picture taken of the breast using sound waves) or a biopsy (removing tissue samples to be looked at closely under a microscope). You may be referred to a breast specialist or a surgeon, because these doctors are experts in diagnosing breast problems. Treatment is most effective when breast cancer is found early, and many women go on to live long and healthy lives. How can I prevent breast cancer?
Scientists are studying how best to prevent breast cancer. There are things you can do to help lower your risk of getting breast cancer, including:
- Staying physically active with regular exercise
- Maintaining a healthy weight
- Avoiding hormone replacement therapy (HRT), or finding out the risks and benefits of HRT and if it is right for you
- Limiting the amount of alcohol that you drink
Check out your risk of getting breast cancer using The Breast Cancer Risk Assessment Tool .
This is an interactive tool that allows doctors to estimate a woman’s absolute risk of developing invasive breast cancer over the next 5 years for women age 35 to 90 years (lifetime risk) based on the woman’s age and the risk factor information provided.
Colorectal Cancer
Colorectal cancer is cancer of the rectum or colon. It’s the second leading cause of cancer-related death for both men and women.
People over the age of 50 are at the highest risk for colorectal cancer. Other risk factors include:
- Growths (called polyps) inside the colon
- Family history of colorectal cancer
- Smoking
- Health conditions like Crohn’s Disease
- Being African-American
Here’s the good news: you can reduce your risk if you get screened for colorectal cancer starting at the age of 50. You can also reduce your risk of colorectal cancer by:
- Getting active
- Eating healthy
- Quitting smoking
Check out your risk of getting colorectal cancer using the The Colorectal Cancer Risk Assessment Tool .
This is an interactive tool designed to help people and their healthcare providers make informed choices about colorectal screening. The tool uses a respondent’s answers to an online questionnaire to calculate that person’s 5-year, 10-year, and lifetime risk of developing colorectal cancer.
Lung Cancer
Lung cancer is one of the most common cancers in the world. It is a leading cause of cancer death in men and women in the United States. Cigarette smoking causes most lung cancers. The more cigarettes you smoke per day and the earlier you started smoking, the greater your risk of lung cancer. High levels of pollution, radiation and asbestos exposure may also increase risk.
Common symptoms of lung cancer include
- A cough that doesn’t go away and gets worse over time
- Constant chest pain
- Coughing up blood
- Shortness of breath, wheezing, or hoarseness
- Repeated problems with pneumonia or bronchitis
- Swelling of the neck and face
- Loss of appetite or weight loss
- Fatigue
There are many types of lung cancer. Each type of lung cancer grows and spreads in different ways and is treated differently. Treatment also depends on the stage, or how advanced it is. Treatment may include chemotherapy, radiation and surgery.
Ovarian Cancer
The sooner ovarian cancer is found and treated, the better your chance for recovery. But ovarian cancer is hard to detect early. Many times, women with ovarian cancer have no symptoms or just mild symptoms until the disease is in an advanced stage and hard to treat. Symptoms may include:
- Heavy feeling in pelvis
- Pain in lower abdomen
- Bleeding from the vagina
- Weight gain or loss
- Abnormal periods
- Unexplained back pain that gets worse
- Gas, nausea, vomiting, or loss of appetite
Treatment is usually surgery followed by treatment with medicines called chemotherapy.
Prostate Cancer
Prostate cancer is the most common cancer in men. Ask your doctor about the potential benefits and harms of prostate cancer screening tests.
Cancer is a disease in which abnormal cells in the body grow out of control. When cancer starts in the prostate, it is called prostate cancer. The prostate is a walnut-sized organ located just below the bladder and in front of the rectum in men. It produces fluid that makes up a part of semen.
Prostate cancer is the most commonly diagnosed cancer in men, and second only to lung cancer in the number of cancer deaths. In 2007 (the most recent year for which statistics are available), 223,307 men were diagnosed with prostate cancer, and 29,093 men died from it.
Symptoms
Different people have different symptoms for prostate cancer. Some men do not have symptoms at all. Some symptoms of prostate cancer are
- Difficulty in starting urination.
- Weak or interrupted flow of urine.
- Frequent urination, especially at night.
- Difficulty in emptying the bladder completely.
- Pain or burning during urination.
- Blood in the urine or semen.
- Pain in the back, hips, or pelvis that doesn’t go away.
- Painful ejaculation.
If you have any symptoms that worry you, be sure to see your doctor right away. These symptoms may be caused by conditions other than prostate cancer.
Risk Factors
There is no way to know for sure if you will get prostate cancer. Men have a greater chance of getting prostate cancer if they are 50 years old or older, are African-American, or have a father, brother, or son who has had prostate cancer.
Screening for Prostate Cancer
Not all medical experts agree that screening for prostate cancer will save lives. Currently, there is not enough credible evidence to decide if the potential benefit of prostate cancer screening outweighs the potential risks. The potential benefit of prostate cancer screening is early detection of cancer, which may make treatment more effective. Potential risks include false positive test results (the test says you have cancer when you do not), treatment of prostate cancers that may never affect your health, and mild to serious side effects from treatment of prostate cancer.
Most organizations recommend that men discuss with their doctors the benefits and risks of prostate cancer screening. CDC supports informed decision making, which encourages men to talk with their doctors to learn the nature and risk of prostate cancer, understand the benefits and risks of the screening tests, and make decisions consistent with their preferences and values.
Tests that are commonly used to screen for prostate cancer are—
- Digital rectal exam (DRE): A doctor, nurse, or other health care professional places a gloved finger into the rectum to feel the size, shape, and hardness of the prostate gland.
- Prostate specific antigen test (PSA): PSA is a substance made by the prostate. The PSA test measures the level of PSA in the blood, which may be higher in men who have prostate cancer. However, other conditions such as an enlarged prostate, prostate infections, and certain medical procedures also may increase PSA levels.
Sources
Source: Cancer , NIH: National Cancer Institute via MedlinePlus, http://www.nlm.nih.gov/medlineplus/cancer.html
Skin Cancer: Basic Information , CDC, http://www.cdc.gov/cancer/skin/basic_info/index.htm
Skin Cancer: Skin Cancer , National Cancer Institute, http://www.cancer.gov/cancertopics/types/skin
What is breast cancer?: Breast Cancer Facts, CDC, www.cdc.gov/cancer/nbccedp/pdf/toolkit/NBCCEDP_2011_BCFacts_Gen_508.pdf
Colorectal Cancer: NIH: National Cancer Institute, http://www.nlm.nih.gov/medlineplus/lungcancer.html
Lung Cancer: Lung Cancer , NIH: National Cancer Institute, http://www.nlm.nih.gov/medlineplus/lungcancer.html
Prostate Cancer: U.S. Cancer Statistics Working Group . //United States Cancer Statistics: 1999–2007 Incidence and Mortality Web-based Report.// Atlanta (GA): Department of Health and Human Services, Centers for Disease Control and Prevention, and National Cancer Institute; 2010. Available at: http://www.cdc.gov/uscs .