All cancers begin in the body’s cells.
Normal cells grow and divide to produce more cells as older cells die off. This keeps the body healthy. However, if the genetic material (DNA) of a cell is damaged or changed, the abnormal cells can develop. These cancer cells can spread through the blood and lymph systems to other parts of the body. The extra cells form a mass of tissue called a tumor.
The National Cancer Institute (NCI) defines cancer as a group of more than 100 related but separate diseases. Cancer is categorized by where the disease begins in the body and not by where it has spread. Here are the main categories of cancer:
- Carcinoma begins in the skin or tissues that line or cover internal organs.
- Sarcoma begins in bone, cartilage, fat, muscle, blood vessels or other connective or supportive tissue.
- Leukemia starts in blood-forming tissue, such as the bone marrow, and causes abnormal blood cells to be produced.
- Lymphoma and myeloma begin in the cells of the immune system.
- Central nervous system cancers begin in the tissues of the brain and spinal cord.
Not all tumors are cancerous. They can be benign (noncancerous) or malignant (cancerous). Cells in malignant tumors are abnormal and divide without control or order. They metastasize or spread and destroy the tissue around them. Cancer cells spread through the blood and lymph systems.
Certain factors can change normal genes into those that allow the growth of cancer. These factors include tobacco use, dietary choices and too much exposure to ultraviolet light, chemicals or certain substances. The risk of developing certain types of cancer might also be inherited. If there is a history of specific types of cancer in your family, such as breast or colon cancers, talk with your healthcare provider. Discuss a referral to test for your genetic risk. However, even if a genetic risk exists, cancer may never actually develop.
It is not your fault if you get cancer. There are many cancer myths about what causes the disease. Wrong beliefs that are shared by others can be hurtful and confusing. For example, it is not true that someone who has the disease can spread cancer. An injury or bruise does not cause cancer. If you are unsure about what you hear or read, talk with your healthcare team.
Cancer may be discovered through:
- Routine physical exams
- Follow-up exams because of a lump or growth
- Lab testing of blood, urine or tissue
- Screening tests, such as a Pap smear, mammogram, fecal occult blood test or a colonoscopy
- X-rays and digital imaging done for other reasons such as an injury. Digital imaging may include computed tomography (CT or CAT) scans, positron emission tomography (PET) scans, or magnetic resonance imaging (MRI) testing.
If cancer is suspected, your healthcare provider will schedule tests to confirm a diagnosis. These are some of the most common tests:
- Biopsy involves either surgery or a hollow needle. A small amount of tissue, bone or bone marrow is extracted. The sample is then sent to a pathology lab to check for cancer cells under a microscope.
- Blood or urine testing is done to learn more about the type of cancer and if it is affecting other parts of the body.
- Imaging studies (such as a CT, PET or MRI scan) show the presence, location and size of an abnormal mass (tumor).
Before you go through testing, ask your healthcare team if some types of tests are better for your diagnosis than others. For example, if you want to have children in the future, your provider may decide to avoid certain types of procedures. It is always good to ask a friend or loved one to go with you to medical appointments.
Talking To Your Cancer Care Team About Tests
Some medications used during testing have side effects, such as fatigue. Be sure to tell your healthcare provider about any physical and emotional concerns that you have as you go through the diagnosis process. Concerns could include depression, fatigue, pain, sexual issues, digestion and urinary or bowel problems. Information that you share can help your provider make the diagnosis and plan for the best treatment.
Your healthcare provider may prescribe further testing to identify the stage of cancer. The stage describes how cancer has affected the body.
Cancer stages are based on:
- The size of a tumor
- Whether cancer is in the lymph nodes
- Whether cancer has spread to other parts of the body (metastatic) or is limited to a certain area (localized).
Early diagnosis and treatment methods have greatly improved the chance of recovery for many types of cancer. Testing has become more accurate. It is a good idea to get other medical opinions before making decisions about treatment. Getting a second medical opinion may help you make the best decision and our medical oncologists are more than happy to provide that for you.