Doctors use imaging tests to make pictures (images) of the inside of the body. Imaging tests can be used in many ways, including to look for cancer, to find out how far it has spread, and to help determine if cancer treatment is working.
Some of the common types of imaging tests include:
- Ultrasound
- Computed Tomography (CT)
- Magnetic Resonance Imaging (MRI)
- Positron Emission Tomography (PET)
- Bone Scan
- Mammogram
During a biopsy procedure a small tissue specimen from the area of concern is removed for examination under a microscope. This can be done with a hollow needle under a local anesthetic using ultrasound or CT guidance, or may be performed through a scope. A number of flexible scopes can be used to guide the biopsy procedure such as an endoscope into the stomach (often referred to as an EGD or upper GI endoscopy), the colon (colonoscopy), the bladder (cystoscopy), or the airways of the lungs (bronchoscopy). Depending on the location of the suspected tumor in the body, a biopsy procedure can be done by a pathologist, surgeon, radiologist or other specialist.
Needle biopsy is used to collect samples of tissues from the body. The different types of needle biopsy include:
- Core needle biopsy: These uses a medium-sized needle to extract a column of tissue, in the same way that a core sample is taken from the earth
- Fine needle biopsies: This uses an ultrasound-guided thin needle to remove cells for testing
- Endobronchial ultrasound (EBUS) with biopsy: This advanced, image-guided biopsy technique combines ultrasound with a bronchoscope for precision in obtaining a biopsy
- Endoscopic ultrasound (EUS) with biopsy: This imaging technology that adds ultrasound to endoscopy to access the lungs and nearby structures
- Image guided biopsy: An imaging procedures—such as an ultrasound or a CT scan — guides your doctor to target specific areas, such as the lung, liver, or other organs
- Vacuum-assisted biopsy: These use suction from a vacuum to collect cells
A bone marrow biopsy takes tissue from the center of the bone for analysis. Typically a hollow needle is placed into the back of the large bone in the pelvic area called the posterior iliac crest, under either local anesthetic or conscious sedation. The needle is inserted through a small incision. Though preliminary results can be available in a day or two, an extensive analysis can take two to three weeks.
At the Hunt Cancer Institute, we are able to perform a complete blood count (commonly called a "CBC") with just a finger-stick and to obtain a result within minutes. The test measures the levels of various blood elements including number and subtypes of white blood cells, quantity of red blood cells, and numbers of platelets. White blood cells fight infection and when low in number place a patient at risk of infection. Red blood cells carry oxygen and when low in number results in fatigue. Platelets prevent or help stop bleeding. CBC results can help diagnose cancer, or help with monitoring treatment side effects.
Chemistry (metabolic) panels measure a variety of organ functions. Our metabolic panel includes measurements of electrolytes, kidney function, nutritional level, and potential damage to the liver and skeletal system. The electrolytes include levels of sodium, potassium, chloride, and carbon dioxide. Kidney function is measured by BUN and creatinine and high levels are undesirable. Albumin, a protein made by the liver, will be low if nutrition is poor or there is dysfunction of the liver. Liver function tests also include bilirubin, transaminases (AST and ALT), and alkaline phosphatase. Mild elevation of liver tests is common and doesn't usually indicate disease. Persistently significant elevations are undesirable and require evaluation. Alkaline phosphatase can also be elevated due to skeletal system damage.
Tumor markers are substances that can be found in the body when cancer is present. The classic tumor marker is a protein found in higher amounts in the blood when a certain type of cancer is present. Other tumor markers are found in urine or other body fluid, and some are found in tumors and other tissue. The tumor marker may be made by the cancer cells themselves, or by the body in response to cancer or other conditions. Most tumor markers are proteins, but some newer markers are genes or other substances.
There are many different tumor markers. Some are linked only to one type of cancer, while others can be found in many types of cancer.
To test for a tumor marker, the doctor most often sends a sample of the patient's blood or urine to a lab. Sometimes a piece of the tumor itself is tested for tumor markers.
Tumor markers alone are rarely enough to show that cancer is present. Most tumor markers can be made by normal cells as well as by cancer cells. Sometimes non-cancerous diseases can also cause levels of certain tumor markers to be higher than normal. And not every person with cancer has higher levels of a tumor marker.
This is why the clinical judgment of a medical oncologist is essential for determining whether or not the use of a tumor marker will result in better treatment for a patient. When a doctor looks at the level of a tumor marker, he or she will consider it along with the patient's history, physical exam, and other lab tests or imaging studies.
