This section contains text excerpted from the following sources: Text beginning with the heading “What Is Cancer?” is excerpted from “Understanding Cancer—What Is Cancer?” National Cancer Institute (NCI), February 9, 2015; Text under the heading “Aging—An Important Risk Factor” is excerpted from “About Cancer—Causes and Prevention—Risk Factors,” National Cancer Institute (NCI), April 29, 2015.
Cancer is the name given to a collection of related diseases. In all types of cancer, some of the body's cells begin to divide without stopping and spread into surrounding tissues.
Cancer can start almost anywhere in the human body, which is made up of trillions of cells. Normally, human cells grow and divide to form new cells as the body needs them. When cells grow old or become damaged, they die, and new cells take their place.
When cancer develops, however, this orderly process breaks down. As cells become more and more abnormal, old or damaged cells survive when they should die, and new cells form when they are not needed. These extra cells can divide without stopping and may form growths called tumors.
Many cancers form solid tumors, which are masses of tissue. Cancers of the blood, such as leukemias, generally do not form solid tumors.
Cancerous tumors are malignant, which means they can spread into, or invade, nearby tissues. In addition, as these tumors grow, some cancer cells can break off and travel to distant places in the body through the blood, or the lymph system, and form new tumors far from the original tumor.
Unlike malignant tumors, benign tumors do not spread into, or invade, nearby tissues. Benign tumors can sometimes be quite large, however. When removed, they usually don't grow back, whereas malignant tumors sometimes do. Unlike most benign tumors elsewhere in the body, benign brain tumors can be life threatening.
There are more than 100 types of cancer. Types of cancer are usually named for the organs or tissues where the cancers form. For example, lung cancer starts in cells of the lung, and brain cancer starts in cells of the brain. Cancers also may be described by the type of cell that formed them, such as an epithelial cell or a squamous cell.
Advancing age is the most important risk factor for cancer overall, and for many individual cancer types. According to statistical data from National Cancer Institute's (NCI) Surveillance, Epidemiology, and End Results (SEER) program, the median age of a cancer diagnosis is 66 years. This means that half of cancer cases occur in people below this age and half in people above this age. One-quarter of new cancer cases are diagnosed in people aged 65 to 74.
A similar pattern is seen for many common cancer types. For example, the median age at diagnosis is 61 years for breast cancer, 68 years for colorectal cancer, 70 years for lung cancer, and 66 years for prostate cancer.
But the disease can occur at any age. For example, bone cancer is most frequently diagnosed among people under age 20, with more than one-fourth of cases occurring in this age group. And 10 percent of leukemias are diagnosed in children and adolescents under 20 years of age, whereas only 1 percent of cancer overall is diagnosed in that age group. Some types of cancer, such as neuroblastoma, are more common in children or adolescents than in adults.
This section includes text excerpted from “Breast Cancer—Basic Information,” Centers for Disease Control and Prevention (CDC), April 4, 2016.
Breast cancer is a disease in which cells in the breast grow out of control. There are different kinds of breast cancer. The kind of breast cancer depends on which cells in the breast turn into cancer.
Breast cancer can begin in different parts of the breast. A breast is made up of three main parts: lobules, ducts, and connective tissue. The lobules are the glands that produce milk. The ducts are tubes that carry milk to the nipple. The connective tissue (which consists of fibrous and fatty tissue) surrounds and holds everything together. Most breast cancers begin in the ducts or lobules.
Breast cancer can spread outside the breast through blood vessels and lymph vessels. When breast cancer spreads to other parts of the body, it is said to have metastasized.
The most common kinds of breast cancer are:
Ductal carcinoma in situ (DCIS) is a breast disease that may lead to breast cancer. The cancer cells are only in the lining of the ducts, and have not spread to other tissues in the breast.
Different people have different symptoms of breast cancer. Some people do not have any signs or symptoms at all. A person may find out they have breast cancer after a routine mammogram.
Some warning signs of breast cancer are:
Keep in mind that these symptoms can happen with other conditions that are not cancer. If you have any signs or symptoms that worry you, be sure to see your doctor right away.
No breast is typical. What is normal for you may not be normal for another woman. Most women say their breasts feel lumpy or uneven.
The way your breasts look and feel can be affected by getting your period, having children, losing or gaining weight, and taking certain medications. Breasts also tend to change as you age.
Many conditions can cause lumps in the breast, including cancer. But most breast lumps are caused by other medical conditions. The two most common causes of breast lumps are fibrocystic breast condition and cysts. Fibrocystic condition causes noncancerous changes in the breast that can make them lumpy, tender, and sore. Cysts are small fluid-filled sacs that can develop in the breast.
Studies have shown that your risk for breast cancer is due to a combination of factors. The main factors that influence your risk include being a woman and getting older. Most breast cancers are found in women who are 50 years old or older.
Some women will get breast cancer even without any other risk factors that they know of. Having a risk factor does not mean you will get the disease, and not all risk factors have the same effect. Most women have some risk factors, but most women do not get breast cancer. If you have breast cancer risk factors, talk with your doctor about ways you can lower your risk, and about screening for breast cancer.
Your risk of getting breast cancer increases as you get older. Most breast cancers are diagnosed after age 50.
Other risk factors include having:
Research suggests that other factors such as smoking, being exposed to chemicals that can cause cancer, and night shift working also may increase breast cancer risk.
Breast cancer screening means checking a woman's breasts for cancer before there are signs or symptoms of the disease. All women need to be informed by their healthcare provider about the best screening options for them. When you are told about the benefits and risks, and decide with your healthcare provider what screening test, if any, is right for you, this is called informed and shared decision-making. Although breast cancer screening cannot prevent breast cancer, it can help find breast cancer early, when it is easier to treat. Talk to your doctor about which breast cancer screening tests are right for you, and when you should have them.
The United States Preventive Services Task Force (USPSTF) recommends that women who are 50 to 74 years old, and are at average risk for breast cancer, get mammogram every two years. Women who are 40 to 49 years old should talk to their doctor or other healthcare professional about when to start and how often to get a mammogram. Women should weigh the benefits and risks of screening tests when deciding whether to begin getting mammograms at age 40.
A mammogram is an X-ray of the breast. Mammograms are the best way to find breast cancer early, when it is easier to treat, and before it is big enough to feel or cause symptoms. Having regular mammograms can lower the risk of dying from breast cancer.
Breast Magnetic Resonance Imaging (MRI)
You can get screened for breast cancer at a clinic, hospital, or doctor's office. If you want to be screened for breast cancer, call your doctor's office. They can help you schedule an appointment. Most health insurance plans are required to cover mammograms every one to two years for women beginning at age 40 with no out-of-pocket cost (like a copay, deductible, or coinsurance).
At this time, the best way to find breast cancer is with a mammogram.
Clinical Breast Exam
A clinical breast exam is an examination by a doctor or nurse, who uses his or her hands to feel for lumps or other changes.
Being familiar with how your breasts look and feel can help you notice symptoms such as lumps, pain, or changes in size that may be of concern. These could include changes found during a breast self-exam. You should report any changes that you notice to your doctor or healthcare provider. Having a clinical breast exam or doing a breast self-exam has not been found to lower the risk of dying from breast cancer.
Doctors often use additional tests to find or diagnose breast cancer. They may refer women to a breast specialist or a surgeon. This does not mean that she has cancer or that she needs surgery. These doctors are experts in diagnosing breast problems.
If breast cancer is diagnosed, other tests are done to find out if cancer cells have spread within the breast or to other parts of the body. This process is called staging. Whether the cancer is only in the breast, is found in lymph nodes under your arm, or has spread outside the breast determines your stage of breast cancer. The type and stage of breast cancer tells doctors what kind of treatment you need.
Breast cancer is treated in several ways. It depends on the kind of breast cancer and how far it has spread. People with breast cancer often get more than one kind of treatment.
Doctors from different specialties often work together to treat breast cancer. Surgeons are doctors who perform operations. Medical oncologists are doctors who treat cancer with medicine. Radiation oncologists are doctors who treat cancer with radiation.
Complementary and alternative medicine are medicines and health practices that are not standard cancer treatments. Complementary medicine is used in addition to standard treatments, and alternative medicine is used instead of standard treatments. Meditation, yoga, and supplements like vitamins and herbs are some examples. Many kinds of complementary and alternative medicine have not been tested scientifically and may not be safe. Talk to your doctor about the risks and benefits before you start any kind of complementary or alternative medicine.
This section contains text excerpted from the following sources: Text beginning with the heading “What Is Colorectal Cancer?” is excerpted from “Colorectal Cancer—Basic Information,” Centers for Disease Control and Prevention (CDC), April 25, 2016; Text under the heading “How Is Colon Cancer Treated?” is excerpted from “Colon Cancer Treatment (PDQ®)—Patient Version,” National Cancer Institute (NCI), February 27, 2017; Text under the heading “How Is Rectal Cancer Treated?” is excerpted from “Rectal Cancer Treatment (PDQ®)—Patient Version,” National Cancer Institute (NCI), May 19, 2017.
Colorectal cancer is cancer that occurs in the colon or rectum. Sometimes it is called colon cancer, for short. As the drawing shows, the colon is the large intestine or large bowel. The rectum is the passageway that connects the colon to the anus.
Sometimes abnormal growths, called polyps, form in the colon or rectum. Over time, some polyps may turn into cancer. Screening tests can find polyps so they can be removed before turning into cancer. Screening also helps find colorectal cancer at an early stage, when treatment often leads to a cure.
Your risk of getting colorectal cancer increases as you get older. More than 90 percent of cases occur in people who are 50 years old or older.
Other risk factors include having:
Lifestyle factors that may contribute to an increased risk of colorectal cancer include:
Colorectal polyps and colorectal cancer don't always cause symptoms, especially at first. Someone could have polyps or colorectal cancer and not know it. That is why getting screened regularly for colorectal cancer is so important.
If you have symptoms, they may include:
If you have any of these symptoms, talk to your doctor. They may be caused by something other than cancer. The only way to know what is causing them is to see your doctor.
A screening test is used to look for a disease when a person doesn't have symptoms. (When a person has symptoms, diagnostic tests are used to find out the cause of the symptoms.)
Colorectal cancer almost always develops from precancerous polyps (abnormal growths) in the colon or rectum. Screening tests can find precancerous polyps, so that they can be removed before they turn into cancer. Screening tests can also find colorectal cancer early, when treatment works best.
The United States Preventive Services Task Force (USPSTF) recommends that adults age 50 to 75 be screened for colorectal cancer. The decision to be screened after age 75 should be made on an individual basis. If you are older than 75, ask your doctor if you should be screened. People at an increased risk of developing colorectal cancer should talk to their doctors about when to begin screening, which test is right for them, and how often to get tested.
Several screening tests can be used to find polyps or colorectal cancer. The Task Force outlines the following colorectal cancer screening strategies. Talk to your doctor about which of the following tests are right for you.
For this test, the doctor puts a short, thin, flexible, lighted tube into your rectum. The doctor checks for polyps or cancer inside the rectum and lower third of the colon.
How often: Every 5 years, or every 10 years with a FIT every year.
This is similar to flexible sigmoidoscopy, except the doctor uses a longer, thin, flexible, lighted tube to check for polyps or cancer inside the rectum and the entire colon. During the test, the doctor can find and remove most polyps and some cancers. Colonoscopy also is used as a follow-up test if anything unusual is found during one of the other screening tests.
How often: Every 10 years.
Computed tomography (CT) colonography, also called a virtual colonoscopy, uses X-rays and computers to produce images of the entire colon, which are displayed on a computer screen for the doctor to analyze.
How often: Every 5 years.
There is no single “best test” for any person. Each test has advantages and disadvantages. Talk to your doctor about the pros and cons of each test, and how often to be tested. Which test to use depends on:
Six types of standard treatment are used:
Five types of standard treatment are used:
This section includes text excerpted from “Prostate Cancer,” Centers for Disease Control and Prevention (CDC), February 27, 2017.
Prostate cancer is the most common nonskin cancer among American men. Prostate cancers usually grow slowly. Most men with prostate cancer are older than 65 years and do not die from the disease.
When cancer starts in the prostate, it is called prostate cancer. Except for skin cancer, prostate cancer is the most common cancer in American men.
The prostate is a part of the male reproductive system, which includes the penis, prostate, and testicles. The prostate is located just below the bladder and in front of the rectum. It is about the size of a walnut and surrounds the urethra (the tube that empties urine from the bladder). It produces fluid that makes up a part of semen.
As a man ages, the prostate tends to increase in size. This can cause the urethra to narrow and decrease urine flow. This is called benign prostatic hyperplasia, and it is not the same as prostate cancer. Men may also have other prostate changes that are not cancer.
The older a man is, the greater his risk for getting prostate cancer. Research has found other risk factors that increase your chances of getting prostate cancer.
These risk factors include:
Researchers are trying to determine the causes of prostate cancer and whether it can be prevented. They do not yet agree on the factors that can influence a man's risk of developing the disease, either positively or negatively.
Cancer screening means looking for cancer before it causes symptoms. However, most prostate cancers grow slowly or not at all.
Two tests are commonly used to screen for prostate cancer:
As a rule, the higher the PSA level in the blood, the more likely a prostate problem is present. But many factors, such as age and race, can affect PSA levels. Some prostate glands make more PSA than others. PSA levels also can be affected by:
Because many factors can affect PSA levels, your doctor is the best person to interpret your PSA test results. Only a biopsy can diagnose prostate cancer for sure.
If your PSA test or DRE is abnormal, doctors may do more tests to find or diagnose prostate cancer.
A biopsy is when a small piece of tissue is removed from the prostate and looked at under a microscope to see if there are cancer cells.
A Gleason score is determined when the biopsy is looked at under the microscope. If there is a cancer, the score indicates how likely it is to spread. The score ranges from 2 to 10. The lower the score, the less likely it is that the cancer will spread.
A biopsy is the main tool for diagnosing prostate cancer, but a doctor can use other tools to help make sure the biopsy is made in the right place. For example, doctors may use a transrectal ultrasound, when a probe the size of a finger is inserted into the rectum and high-energy sound waves (ultrasound) are bounced off the prostate to create a picture of the prostate called a sonogram. Doctors also may use magnetic resonance imaging (MRI) to guide the biopsy.
If prostate cancer is diagnosed, other tests are done to find out if cancer cells have spread within the prostate or to other parts of the body. This process is called staging. Whether the cancer is only in the prostate, or has spread outside the prostate, determines your stage of prostate cancer. The stage of prostate cancer tells doctors what kind of treatment you need.
Different types of treatment are available for prostate cancer. You and your doctor will decide which treatment is right for you. Some common treatments are:
Other therapies used in the treatment of prostate cancer that are still under investigation include: