Cancer Introduction Cancer begins in your cells, which are the building blocks of your body. Extra cells can form a mass called a tumor. Some tumors aren t cancerous, while other ones are. Cells from cancerous tumors can invade nearby tissues. They can also break away and spread to other parts of the body. This can cause serious health problems. This reference summary helps you better understand cancer. It talks about what cancer is and risk factors for cancer. It also covers how cancer is diagnosed and treated. Understanding Cancer The body is made up of very small cells. Normal cells in the body grow and die in a controlled way. Sometimes cells keep dividing and growing. These extra cells cause an abnormal growth. This growth is called a tumor. If the tumor does not invade tissues and body parts, it is called a benign tumor. It is also called a non-cancerous growth. Benign tumors are often not life threatening. A malignant tumor invades nearby tissues and body parts. It is also called cancer. Cancer cells are able to spread to different parts of the body. They can spread through blood vessels and lymph channels. Lymph is a clear fluid made by the body that drains waste from cells. It travels through special vessels and bean-shaped structures called lymph nodes. 1
Cancer that moves from one tissue to other body parts is known as metastatic cancer. For example, a lung tumor may grow through the lung s outer layer. It can then grow into nearby tissues over time. Cancers in the body are given names. These names depend on where the cancer started. Cancer that begins in the breast will always be called breast cancer, even if it spreads to other places. Risk Factors It is usually impossible to specify the cause of cancer in an individual. But we do know what causes cancer in general. Health care providers also know factors that can increase the chances of getting cancer. These are known as risk factors. The most common risk factors for cancer are: Smoking or chewing tobacco. Exposure to certain chemicals in the workplace. Family history of cancer. Drinking alcohol. Growing older. Over-exposure to sunlight. Poor diet, lack of physical activity, or being overweight. Ionizing radiation exposure is also a risk factor for some types of cancer. This type of radiation can cause cell damage. Cell damage can lead to cancer. Some sources of this type of radiation are x-rays or radioactive fallout. Another risk factor for some cancers is being infected with certain viruses and bacteria. Examples are: Human papillomaviruses, or HPVs. These are the main cause of cervical cancer. Hepatitis B and C viruses. These can lead to liver cancer. Human immunodeficiency virus, or HIV. This raises the risk for lymphoma. Lymphoma is cancer of the lymphatic system. In some cases, hormones can also raise the risk of cancer. Hormones may be given in medicines to treat problems caused by menopause. These hormones and others can raise the risk for breast and cervical cancer in women. 2
Not everybody who has risk factors for cancer gets it. Some people who have no risk factors for cancer can still get cancer. Screening Some types of cancer can be found before they cause symptoms. Checking for cancer or conditions that can lead to cancer in people who have no symptoms is called screening. Screening can help health care providers find and treat some types of cancer early. Generally, cancer treatment is more successful when the disease is found early. Screening tests are often used to check for cancers of the skin, breast, cervix, colon, and rectum. This section discusses some of these tests. A check up with your health care provider or dermatologist once a year may help detect skin cancer early. Breast cancer screening is done using a test called a mammogram. A mammogram is a picture of the breast made with x-rays. Women in their forties and older should be screened for breast cancer every one to two years. Women with higher risk may be screened earlier and more often. A Pap test is used to check cells from the cervix to screen for cervical cancer. During a Pap test, a sample of cells is scraped from the cervix. The sample is then checked in the lab for cancer or changes that may lead to cancer. Women should have Pap tests at least once every three years. This usually begins three years after they start having sex or when they reach age 21. A number of screening tests are available to detect cancer or changes that can lead to cancer in the colon and rectum. The most common screening tests used are the colonoscopy and the fecal occult blood test, or FOBT. A colonoscopy is a procedure that allows a health care provider to look inside the entire colon and rectum. It can find cancer very early. During the test, small samples may be taken from polyps or polyps may be removed completely. A polyp is a mass of tissue that grows inside the colon. Polyps may bleed from time to time. Some polyps can turn into cancer over time if they are not removed early. When a health care provider takes a sample of a tumor or cancer, the test is known as a biopsy. 3
Blood in your stool may be found by a screening test like FOBT. This may be a warning sign that you have colorectal cancer. But, a colonoscopy can find polyps earlier, even before they bleed or become cancer. It also allows the health care provider to remove polyps if they are found. All people who are 50 years of age and older should get screened for cancer in the colon or rectum, also called colorectal cancer. Some people may need to be screened earlier because they may be more likely to get colorectal cancer. Talk to your health care provider about recommended screening tests. Ask about the possible benefits and harms of being checked for cancer. Symptoms Cancer can cause many different symptoms. Some common symptoms include: A thickening or lump in the breast or any other part of the body. A sore that does not heal. Feeling weak or very tired. Weight gain or loss with no known reason. Other common symptoms of cancer include: A new mole or a change in an existing mole. Changes in bowel or bladder habits. Difficulty swallowing. Discomfort after eating. Hoarseness or a cough that does not go away. Unusual bleeding or discharge. These symptoms may not be caused by cancer. Make sure to see a health care provider to find out what is causing your symptoms. Early cancer often does not cause pain. Do not wait for pain to see a health care provider. Diagnosis If you have symptoms of cancer or your screening test suggests cancer, your health care provider will try to find out if cancer is the cause. There may be some other cause. 4
Your health care provider will ask about your family medical history in addition to your own. A physical exam will be performed. Your health care provider may also order lab tests, x-rays, or other tests or procedures. Lab tests of the blood, urine, or other fluids can help diagnose cancer. These tests can show how well an organ, such as the kidney, is doing its job. High amounts of some substances may also be a sign of cancer. But lab tests alone cannot diagnose cancer. Imaging tests can be used to create pictures of areas inside your body. These pictures can show if a tumor is present. Imaging tests that may be done include: X-rays. CT scan. Ultrasound. MRI. PET scan. A CT scan is an x-ray machine linked to a computer. A CT scan takes a series of detailed pictures of your organs. You may be given contrast material by mouth or injection to make abnormal areas easier to see. An ultrasound uses sound waves to make a picture of the inside of the body. The sound waves bounce off internal organs and structures, causing an echo. A computer uses these echoes to create the picture. An MRI uses strong magnets to create images of the inside of the body. You may receive contrast material by injection to make abnormal areas easier to see. A PET scan can show if the cancer has spread. For this test, you are injected with a small and safe amount of radioactive sugar. The PET scanner makes a picture of the places in your body where the sugar is being taken up. Cancer cells show up brighter because they use sugar faster than normal cells. In most cases, health care providers need to do a biopsy to make a diagnosis of cancer. A biopsy is a removal of a sample of cells or tissue. The sample may be removed several ways: With a needle. With a thin, lighted tube called an endoscope. With surgery. 5
A pathologist will then examine the biopsy sample under a microscope to look for cancer cells. A biopsy is the only sure way to know if cancer cells are present. Other tests and procedures may also be done depending on the type of cancer. Talk to your health care provider to learn more about these tests. Staging If you have cancer, your health care provider will determine the stage of the cancer. Staging is an attempt to find out if the cancer has spread and, if so, to which parts of the body. For most cancers, the stages are described using the numbers 1-4. A lower number indicates an earlier stage. Staging is helpful in deciding the best course of treatment. The stage of cancer is determined based on: The size of the tumor. Whether the cancer has spread to lymph nodes. Whether the cancer has spread to other parts of the body. Additional tests may be done to learn the stage of cancer. Sometimes staging is not complete until after surgery to remove the tumor and nearby lymph nodes. Treatment and Supportive Care The type of treatment used depends on the type of cancer. It also depends on the size and location of the tumor, the stage of the disease, and the health of the patient. Often treatment for cancer includes surgery, radiation therapy, chemotherapy, or some combination of these treatments. Surgery for cancer depends on where the cancer is located. In most cases, the surgeon removes the tumor and some tissue around it. Removing nearby tissue may help prevent the tumor from growing back. The surgeon may also remove some nearby lymph nodes. Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. The way the radiation therapy is given depends on the type and stage of the cancer being treated. 6
There are two types of radiation therapy: External radiation therapy uses a machine outside the body to send radiation toward the cancer. Internal radiation therapy places needles, seeds, wires, or catheters containing small amounts of radiation into or near the cancer. Chemotherapy is a cancer treatment that uses drugs to kill cancer cells. Chemotherapy may be given in the blood stream through an IV or taken by mouth. It can also be placed in a specific area of the body. The type used depends on the type and stage of the cancer being treated. Radiation therapy and chemotherapy may sometimes be done together. These treatments may be used on their own, before surgery, or after surgery. Sometimes cancer treatments may also involve: Biological therapy. Hormone therapy. Stem cell transplant. Talk to your health care provider to learn more about your treatment options if you have cancer. Biological therapy uses the body s own natural defense system to fight cancer. It involves treatments that boost or restore the immune system. Hormone therapy is treatment that adds, blocks, or removes certain hormones. This can slow or stop the growth of some types of cancer. A stem cell transplant involves destroying the diseased bone marrow with high doses of drugs and radiation. Then, it is replaced with healthy bone marrow from a donor. There may also be clinical trials available for people with cancer. Clinical trials test new medical approaches and treatments. Cancer and its treatment can lead to other health problems. It is important to have supportive care before, during, and after cancer treatment. Supportive care is treatment to control symptoms, relieve the side effects of therapy, and help you cope with emotions. Supportive care also deals with the pain associated with cancer and its treatments. Your health care provider or a pain control specialist can suggest ways to relieve or reduce pain. 7
Summary Cancer begins in your cells, which are the building blocks of your body. Extra cells can form a mass called a tumor. Some tumors aren t cancerous, while other ones are. Cells from cancerous tumors can invade nearby tissues. They can also break away and spread to other parts of the body, causing serious health problems. Treatment options for cancer usually involve surgery, radiation therapy, chemotherapy, or some combination of these three. Treatment may also include biological therapy, hormone therapy, or a stem cell transplant. Often cancer is most treatable in its early stages. Research already has led to advances that have helped people with cancer live longer. Research continues to find better ways to care for people with cancer. 8