Clinical trials are research studies that evaluate a new medical approach, device, drug, or other treatment. As a Stanford Health Care patient, you have access to the latest, advanced clinical trials.
Open trials refer to studies currently accepting participants. Closed trials are not currently enrolling, but may open in the future.
Before beginning treatment, ask your doctor about any clinical trials you should consider. Learn more about clinical trials for cancer patients.
What Is Cancer?
Cancer is an abnormal growth of cells. Cancer cells rapidly reproduce despite restriction of space, nutrients shared by other cells, or signals sent from the body to stop reproduction. Cancer cells are often shaped differently from healthy cells, they do not function properly, and they can spread to many areas of the body. Tumors, abnormal growth of tissue, are clusters of cells that are capable of growing and dividing uncontrollably; their growth is not regulated.
Oncology is the study of cancer and tumors. The term "cancer" is used when a tumor is malignant, which is to say it has the potential to cause harm, including death.
What is the difference between benign and malignant cancer?
Tumors can be benign (noncancerous) or malignant (cancerous). Benign tumors tend to grow slowly and do not spread. Malignant tumors can grow rapidly, invade and destroy nearby normal tissues, and spread throughout the body.
What are "locally invasive cancer" and "metastatic cancer"?
Cancer is malignant because it can be "locally invasive" and "metastatic":
- Locally invasive cancer—The tumor can invade the tissues surrounding it by sending out "fingers" of cancerous cells into the normal tissue.
- Metastatic cancer—The tumor can send cells into other tissues in the body, which may be distant from the original tumor.
What are primary tumors?
The original tumor is called the "primary tumor." Its cells, which travel through the body, can begin the formation of new tumors in other organs. These new tumors are referred to as "secondary tumors."
The cancerous cells travel through the blood (circulatory system) or lymphatic system to form secondary tumors. The lymphatic system is a series of small vessels that collect waste from cells, carrying it into larger vessels, and finally into lymph nodes. Lymph fluid eventually drains into the bloodstream.
Pain may occur as a result of cancer or for other reasons. Learn more about cancer pain.
Early cancer and certain types of cancer may not have any symptoms. However, some symptoms may be the result of cancer or a less serious illness.
Learn about symptoms for your type of cancer:
What Causes Cancer?
There is no one single cause for cancer. Scientists believe that it is the interaction of many factors together that produces cancer. The factors involved may be genetic, environmental, or constitutional characteristics of the individual.
Diagnosis, treatment, and prognosis for childhood cancers are different than for adult cancers. The main differences are the survival rate and the cause of the cancer. The overall five-year survival rate for childhood cancer is about 80%, while in adult cancers the survival rate is 68%. This difference is thought to be because childhood cancer is more responsive to therapy and a child can tolerate more aggressive therapy.
Childhood cancers often occur or begin in the stem cells, which are simple cells capable of producing other types of specialized cells that the body needs. A sporadic (occurs by chance) cell change or mutation is usually what causes childhood cancer. In adults, the type of cell that becomes cancerous is usually an epithelial cell. Epithelial cells line the body cavity and cover the body surface. Cancer occurs from environmental exposures to these cells over time. Adult cancers are sometimes referred to as acquired for this reason.
Cancer Risk Factors
As mentioned, some cancers, particularly in adults, have been associated with repetitive exposures or risk factors. A risk factor is anything that may increase a person's chance of developing a disease. A risk factor does not necessarily cause the disease, but it may make the body less resistant to it. The following risk factors and mechanisms have been proposed as contributing to cancer:
- Lifestyle factors. Smoking, a high-fat diet, and working with toxic chemicals are examples of lifestyle choices that may be risk factors for some adult cancers. Most children with cancer, however, are too young to have been exposed to these lifestyle factors for any extended time.
- Family history, inheritance, and genetics may play an important role in some childhood cancers. It is possible for cancer of varying forms to be present more than once in a family. It is unknown in these circumstances if the disease is caused by a genetic mutation, exposure to chemicals near a family's residence, a combination of these factors, or simply coincidence.
- Some genetic disorders. For example, Wiskott-Aldrich and Beckwith-Wiedemann syndrome are known to alter the immune system. The immune system is a complex system that functions to protect our bodies from infection and disease. The bone marrow produces cells that later mature and function as part of the immune system. One theory suggests that the cells in the bone marrow, the stem cells, become damaged or defective, so when they reproduce to make more cells, they make abnormal cells or cancer cells. The cause of the defect in the stem cells could be related to an inherited genetic defect or exposure to a virus or toxin.
- Exposures to certain viruses. Epstein-Barr virus and HIV, the virus that causes AIDS, have been linked to an increased risk of developing certain childhood cancers, such as Hodgkin and non-Hodgkin lymphoma. Possibly, the virus alters a cell in some way. That cell then reproduces an altered cell and, eventually, these alterations become a cancer cell that reproduces more cancer cells.
- Environmental exposures. Pesticides, fertilizers, and power lines have been researched for a direct link to childhood cancers. There has been evidence of cancer occurring among nonrelated children in certain neighborhoods and/or cities. Whether prenatal or infant exposure to these agents causes cancer, or whether it is a coincidence, is unknown.
- Some forms of high-dose chemotherapy and radiation. In some cases, children who have been exposed to these agents may develop a second malignancy later in life. These strong anticancer agents can alter cells and/or the immune system. A second malignancy is a cancer that appears as a result from treatment of a different cancer.
How do genes affect cancer growth?
The discovery of certain types of genes that contribute to cancer has been an extremely important development for cancer research. Over 90% of cancers are observed to have some type of genetic alteration. Some of these alterations are inherited, while others are sporadic, which means they occur by chance or occur from environmental exposures (usually over many years).
Types of cancer genes
There are three main types of genes that can affect cell growth and are altered (mutated) in certain types of cancers, including the following:
- Oncogenes: These genes regulate the normal growth of cells. Scientists commonly describe oncogenes as similar to a cancer "switch" that most people have in their bodies. What "flips the switch" to make these oncogenes suddenly become unable to control the normal growth of cells and allowing abnormal cancer cells to begin to grow, is unknown.
- Tumor suppressor genes: These genes are able to recognize abnormal growth and reproduction of damaged cells, or cancer cells, and can interrupt their reproduction until the defect is corrected. If the tumor suppressor genes are mutated, however, and they do not function properly, tumor growth may occur.
- Mismatch-repair genes: These genes help recognize errors when DNA is copied to make a new cell. If the DNA does not "match" perfectly, these genes repair the mismatch and correct the error. If these genes are not working properly, however, errors in DNA can be transmitted to new cells, causing them to be damaged.
Usually the number of cells in any of our body tissues is tightly controlled so that new cells are made for normal growth and development, as well as to replace dying cells. Ultimately, cancer is a loss of this balance due to genetic alterations that "tip the balance" in favor of excessive cell growth.
Types of Cancer
How Is Each Cancer Type Named?
Cancer is named after the part of the body where it originated. When cancer spreads, it keeps this same name. For example, if kidney cancer spreads to the lungs, it is still kidney cancer, not lung cancer. Lung cancer would be an example of a secondary tumor.
Staging is the process of determining whether cancer has spread and, if so, how far. There is more than one system used for staging cancer.
What Are the Different Types of Cancer?
Cancer is not just one disease but rather a group of diseases, all of which cause cells in the body to change and grow out of control. Cancers are classified either according to the kind of fluid or tissue from which they originate, or according to the location in the body where they first developed. In addition, some cancers are of mixed types.
The following five broad categories indicate the tissue and blood classifications of cancer:
A carcinoma is a cancer found in body tissue known as epithelial tissue that covers or lines surfaces of organs, glands, or body structures. For example, a cancer of the lining of the stomach is called a carcinoma. Many carcinomas affect organs or glands that are involved with secretion, such as breasts that produce milk. Carcinomas account for 80-90% of all cancer cases.
Types of carcinoma include:
A sarcoma is a malignant tumor growing from connective tissues, such as cartilage, fat, muscle, tendons, and bones. The most common sarcoma, a tumor on the bone, usually occurs in young adults. Examples of sarcoma include osteosarcoma (bone) and chondrosarcoma (cartilage).
Types of sarcoma include:
Lymphoma refers to a cancer that originates in the nodes or glands of the lymphatic system, whose job it is to produce white blood cells and clean body fluids, or in organs such as the brain and breast. Lymphomas are classified into two categories: Hodgkin's lymphoma and non-Hodgkin's lymphoma.
Types of lymphoma include:
Leukemia, also known as blood cancer, is a cancer of the bone marrow that keeps the marrow from producing normal red and white blood cells and platelets. White blood cells are needed to resist infection. Red blood cells are needed to prevent anemia. Platelets keep the body from easily bruising and bleeding.
Examples of leukemia include acute myelogenous leukemia, chronic myelogenous leukemia, acute lymphocytic leukemia, and chronic lymphocytic leukemia. The terms myelogenous and lymphocytic indicate the type of cells that are involved.
Types of leukemia include:
- Acute lymphocytic leukemia
- Acute myeloid leukemia
- Agnogenic myeloid leukemia
- Chronic lymphocytic leukemia
- Chronic myeloid leukemia
- Essential thrombocythemia (ET)
- Hairy cell leukemia
- Myelodysplastic syndromes (MDS)
Myeloma grows in the plasma cells of bone marrow. In some cases, the myeloma cells collect in one bone and form a single tumor, called a plasmacytoma. However, in other cases, the myeloma cells collect in many bones, forming many bone tumors. This is called multiple myeloma.
How Is Cancer Diagnosed?
There is no single test that can accurately diagnose cancer. The complete evaluation of a patient usually requires a thorough history and physical examination along with diagnostic testing. Many tests are needed to determine whether a person has cancer, or if another condition (such as an infection) is mimicking the symptoms of cancer.
Effective diagnostic testing is used to confirm or eliminate the presence of disease, monitor the disease process, and to plan for and evaluate the effectiveness of treatment. In some cases, it is necessary to repeat testing when a person's condition has changed, if a sample collected was not of good quality, or an abnormal test result needs to be confirmed.
Diagnostic procedures for cancer may include imaging, laboratory tests (including tests for tumor markers), tumor biopsy, endoscopic examination, surgery, or genetic testing.
Cancer diagnosis methods:
- Lab tests
- Diagnostic imaging
- Endoscopic exams
- Genetic tests
- Tumor biopsies
What are the different types of lab tests used to diagnose cancer?
Clinical chemistry uses chemical processes to measure levels of chemical components in body fluids and tissues. The most common specimens used in clinical chemistry are blood and urine.
Many different tests exist to detect and measure almost any type of chemical component in blood or urine. Components may include blood glucose, electrolytes, enzymes, hormones, lipids (fats), other metabolic substances, and proteins.
The following are some of the more common laboratory tests:
Learn more about laboratory tests.
Diagnostic radiology has greatly advanced in recent years with the development of new instruments and techniques that can better detect cancer and also help patients avoid surgery.
The diagnostic radiology staff and physicians at the Stanford Cancer Center are leaders in their field and have access to the most advanced technology available today for imaging of cancer.
In fact, the expertise of our doctors is so well recognized that we proudly serve as a reference center, meaning that outside physicians can send our staff complex or borderline images and receive expert interpretation for their patients.
In addition to advanced instruments and experienced staff, the Cancer Center was designed to improve the delivery of diagnostic radiology. For example, we have consolidated imaging workstations for mammograms, ultrasounds, and magnetic resonance images in one room, allowing physicians to directly compare images from multiple sources.
This unprecedented cross-platform, simultaneous access ensures that all of the relevant data is at your doctor's fingertips when s/he is making important decisions about your care.
What are the different types of diagnostic imaging?
Imaging is the process of producing valuable pictures of body structures and organs. It is used to detect tumors and other abnormalities, to determine the extent of disease, and to evaluate the effectiveness of treatment. Imaging may also be used when performing biopsies and other surgical procedures. There are three types of imaging used for diagnosing cancer: transmission imaging, reflection imaging, and emission imaging. Each uses a different process.
X-rays, computed tomography scans (CT scans), and fluoroscopy are radiological examinations whose images are produced by transmission. In transmission imaging, a beam of high-energy photons is produced and passed through the body structure being examined. The beam passes very quickly through less dense types of tissue such as watery secretions, blood, and fat, leaving a darkened area on the X-ray film. Muscle and connective tissues (ligaments, tendons, and cartilage) appear gray. Bones will appear white.
- Computed tomography scan (also called a CT scan or computed axial tomography or CAT scan)
- Bone scan
- Lymphangiogram (LAG)
Reflection imaging refers to the type of imaging produced by sending high-frequency sounds to the body part or organ being studied. These sound waves "bounce" off of the various types of body tissues and structures at varying speeds, depending on the density of the tissues present. The bounced sound waves are sent to a computer that analyzes the sound waves and produces a visual image of the body part or structure.
Emission imaging occurs when tiny nuclear particles or magnetic energy are detected by a scanner and analyzed by computer to produce an image of the body structure or organ being examined. Nuclear medicine uses emission of nuclear particles from nuclear substances introduced into the body specifically for the examination. Magnetic resonance imaging (MRI) uses radio waves with a machine that creates a strong magnetic field that in turn causes cells to emit their own radio frequencies.
What are the different types of endoscopic examinations used to diagnose cancer?
Types of endoscopies include:
- Cystoscopy (also called cystourethroscopy)
- Endoscopic retrograde cholangiopancreatography (ERCP)
- Esophagogastroduodenoscopy (also called EGD or upper endoscopy)
What are the different types of genetic testing used to diagnose cancer?
Testing for mutations in genes that give an increased risk for cancer is complicated. The concepts are important to understand when considering cancer susceptibility gene testing.
Learn more about:
- Genetic testing for cancer
- Before undergoing genetic testing
- DNA testing
- Types of genetic testing
- Uses of genetic testing
What are the different types of tumor biopsies used to diagnose cancer?
A biopsy is a procedure performed to remove tissue or cells from the body for examination under a microscope. Some biopsies can be performed in a physician's office, while others need to be done in a hospital setting. In addition, some biopsies require use of an anesthetic to numb the area, while others do not require any sedation.
Biopsies are usually performed to determine whether a tumor is malignant (cancerous) or to determine the cause of an unexplained infection or inflammation.
The following are the most common types of biopsies:
Cancer is treated in several ways, depending on each person's medical condition and type of cancer. Common treatments involve chemotherapy and radiation therapy. Other treatments include surgery and biological therapies.
For many people with cancer, treatment is a process that is designed to meet their needs. Doctors plan treatments based on several key factors, such as the type and stage of the cancer, as well as the person's age, health, and lifestyle.
If you have been diagnosed with cancer, it is important for you to know that you play an important role in the treatment process. Offering input, asking questions, and expressing your concerns about treatment can help make treatment a better experience.
Cancer treatment terms you should know
Combined modality therapy: A term used to describe when doctors choose more than one therapy in treating a patient, such as a combination of radiation therapy and chemotherapy.
Adjuvant therapy: A term used to describe when doctors choose more than one therapy in treating a patient. However, the term adjuvant therapy is more specifically used to describe treatment given after the primary cancer treatment is completed to improve the chance of a cure. For example, if the doctor wants to treat cancer cells that may be present, he/she may prescribe one or more additional treatments.
Neoadjuvant therapy: A term used to describe when doctors choose to use more than one therapy in treating a patient. However, the term neoadjuvant therapy is more specifically used to describe cancer treatment given before the primary therapy—both to kill any cancer cells and contribute to the effectiveness of the primary therapy.
Preparing a patient for treatment
How can patients prepare for treatment?
As a patient, you play an important role in preparing for your cancer treatment. The following are some of the most important things to consider before treatment begins:
Find an oncologist and treatment center.
This step is important to everyone with cancer. Ask your general or primary care doctor for a referral to an oncologist. You can also contact government and professional medical organizations, such as your state's health department, the National Cancer Institute (NCI), or the American Medical Association (AMA) for information on cancer specialists and treatment centers in your area.
Get a second opinion.
It is common for people diagnosed with cancer to ask another cancer specialist for their opinion. A second opinion can help you to be sure your diagnosis and treatment plans are most appropriate for your individual medical history and profile. Asking for a second opinion also provides more information to consider when making choices about your treatment. Often, your oncologist can help you locate another cancer specialist for a second opinion.
Find out about your cancer treatment.
Your cancer care team will help you understand your treatment and answer questions. It also helps to learn about the type of cancer you have, as well as your treatment options. Ask your doctor where you can find more information about cancer. The Stanford Cancer Center contains information on many cancer topics. Also, the National Cancer Institute (NCI), the American Cancer Society (ACS), and other cancer- and health-related organizations provide helpful information.
Find support when you need it.
Cancer treatment can be a long and tiring experience. Many people with cancer need help throughout the process. Finding help from others can make your experience more successful. Support groups for people with cancer are available in many communities. Managing your emotional health, your diet, and your finances are all things patients can do to reduce the stress involved in the treatment process. Oncology nurses and social workers are excellent resources for locating appropriate support groups.
Cancer treatment methods
Cancer is treated in several ways, depending on each person's medical condition and type of cancer. Common treatments involve chemotherapy and radiation therapy. Other treatments include surgery and biological therapies.
For many people with cancer, treatment is a process that is designed to meet their needs. Doctors plan treatments based on several key factors, such as the type and stage of the cancer, as well as the person's age, health, and lifestyle. If you have been diagnosed with cancer, it is important for you to know that you play an important role in the treatment process. Offering input, asking questions, and expressing your concerns about treatment can help make treatment a better experience.
There is a great deal of information to learn about the cancer treatment process, including various cancer treatment options—their goals and side effects.
The use of high-energy radiation to kill or shrink cancer cells, tumors, and non-cancerous diseases.
The use of anticancer drugs to shrink or kill cancerous cells and reduce cancer spreading to other parts of the body.
Use of supplemental hormones to prevent or stop the growth or spread of tumors. The type of hormone therapy you receive depends upon many factors, such as the type and size of the tumor, your age, the presence of hormone receptors on the tumor, and other factors.
A specialized therapy to transfer healthy bone marrow cells into a patient after their own unhealthy bone marrow has been eliminated.
Immunotherapy (also called biological therapy, biological response modifier therapy, or biotherapy) is designed to boost the body's immune system in order to fight cancer. The cells, antibodies, and organs of the immune system work to protect and defend the body against foreign invaders, such as bacteria or viruses. Doctors and researchers have found that the immune system might also be able to both determine the difference between healthy cells and cancer cells in the body, and to eliminate the cancer cells.
A substance that may prevent the formation of blood vessels. In anticancer therapy, an angiogenesis inhibitor may prevent the growth of new blood vessels that tumors need to grow.