Doctors may use a variety of laboratory tests if cancer is suspected. In conducting lab tests for cancer, samples of blood, urine, other bodily fluids or tissue are examined for abnormal cells or tumor markers that may determine whether a person has the disease or a precancerous condition.
Lab tests also may be used to screen high-risk patients, pinpoint the stage of cancer, identify treatment options and evaluate whether the cancer is responding to treatment. Lab tests may also be used to determine whether a patient has a cancer recurrence —a disease that has returned to its original location—or whether a new cancer has developed.
Blood tests play an important role in diagnosing and treating cancer. Not only are blood tests useful in determining your overall health, including your kidney and liver function, but the presence of certain chemicals and proteins in the blood can also help your doctor diagnose cancer. While blood tests alone cannot be used to diagnose cancer, when used with additional cancer diagnostic testing such as imaging, they help to guide diagnosis as well as help determine appropriate treatment options.
This diagnostic test helps capture, identify and count circulating tumor cells in a blood sample. CTCs are cancer cells that detach from solid tumors and enter the bloodstream. This cancer blood test may be performed prior to the start of therapy or during the course of treatment. A complete blood count CBC test measures the number of blood cells circulating in the bloodstream. Specifically, this cancer blood test measures a blood sample for the level of red blood cells, which carry oxygen throughout the body; white blood cells, which fight infection; and platelets, which help with blood clotting.
The test also measures hemoglobin, a protein in red blood cells that carries oxygen, and hematocrit, the ratio of red blood cells to plasma.
A CBC may be used to detect a variety of conditions, including leukemia , anemia and infection. This test is used to diagnose and classify certain cancers, such as leukemia and lymphoma, and to evaluate the risk of recurrence. Flow cytometry also may be used as part of the stem cell transplantation process. Flow cytometry measures the properties of cells in a sample of bone marrow, lymph nodes or blood. The sample is first treated with special antibodies and passed in front of a laser beam.
If the antibodies attach to the cells, the cells give off light. The presence of certain substances, or antigens, on the surface of cells may help identify the cell type. Flow cytometry may also be used to measure the amount of DNA in cancer cells.
In this case, the cells are treated with special light-sensitive dyes that react with DNA. For patients with breast, prostate or bladder cancer , an abnormal amount of DNA may indicate a recurrence.
A high-risk score means the cancer has a three-in chance of returning. 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.
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. 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 Stanford Medicine Online Second Opinion program offers you easy access to our world-class doctors. Visit our online second opinion page to learn more. Clinical trials are research studies that evaluate a new medical approach, device, drug, or other treatment.
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Using them to find early signs of cancer in asymptomatic patients would be a new venture, but it may not be far off: Several liquid biopsy candidates are in clinical trials for this purpose.
If they prove effective, they could save lives and money, prompting a change in the medical system. One of the first to imagine a cancer-screening blood test was Nick Papadopoulos, who holds a doctorate in biomedical sciences and is a professor of oncology and pathology at Johns Hopkins University School of Medicine and a member of the Sidney Kimmel Comprehensive Cancer Center there.
Papadopoulos is a co-founder of Thrive Earlier Detection Corp. He says that for 30 or 40 years, scientists have known that some kind of signal must exist in the blood of someone with cancer to broadcast that the disease is there. So what is that signal?
Adam Buchanan, director of Geisinger Genomic Medicine Institute and principal investigator on the DETECT study, says the liquid biopsy looks for protein biomarkers and pieces of DNA that have been shed from a tumor and are circulating through the blood.
These biomarkers can be found in people with numerous cancer types, which means that testing the blood may reveal the presence of cancers that are difficult to detect any other way. In fact, of the more than cancer types that exist, there are screening tests for only five: cervical, breast, prostate, lung and colon, says Sudhir Srivastava, who holds a doctorate in biological science and is senior scientific officer and chief of the Cancer Biomarkers Research Group at the National Cancer Institute.
The real power of these tests, then, lies in finding the remaining plus cancers, says Dr. Joshua Ofman, chief medical officer and head of external affairs for GRAIL, a health care company developing another liquid biopsy.
Sue Friedman, founder and executive director of Facing Our Risk of Cancer Empowered FORCE , a national nonprofit focused on hereditary cancers, is a year breast cancer survivor who has a BRCA gene mutation that puts her at high risk of developing pancreatic cancer.
In addition to screening for cancers that are otherwise hard to detect, liquid biopsies could supplement the effectiveness of other tests and help determine when those tests are necessary — for example, the prostate-specific antigen PSA blood test used to screen for prostate cancer. Perhaps a liquid biopsy test could identify which men with PSAs at that level could benefit from biopsy, he says, allowing doctors to spare the others from the unnecessary procedure and to place them under active surveillance.
Waste chemicals called urea and creatinine are produced by the body. Our kidneys remove them from our blood and get rid of them in our urine. Liver function tests LFTs check how well your liver is working. LFTs look for levels of enzymes and proteins made by the liver or which are cleared by the liver. They include:. They might be raised if you have a blockage in your liver or bile duct, or if you drink a lot of alcohol. Bilirubin can be raised if you have a problem with your liver or gallbladder.
Bilirubin can cause yellowing of your skin and eyes jaundice. LFTs also measure albumin. This is a protein in the blood that can be low in some types of cancer.
Tumour markers are substances that might be raised if there is a cancer. They can be found in the blood, urine or body tissues. Some tumour markers are only produced by one type of cancer. Others can be made by several types. Some markers are found in non cancerous conditions as well as cancer. Doctors might use tumour markers to help diagnose a cancer. And if you have cancer they can also help to monitor how well your cancer treatment is working or check if the cancer has come back. Ask the phlebotomist, doctor or nurse when and how you will get your results.
Some results might be available very quickly, such as a full blood count and kidney and liver function tests. Some other tests might take several weeks.
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