Which Tests are Done to Check for Cancer?

If a medical professional wants to rule out cancer as a possibility, or suspects cancer may be the root cause of a medical issue, they will order one or more tests. Below are some examples of tests that may be given to either confirm a cancer diagnosis or rule one out.

Tests can cause feelings of apprehension and discomfort often referred to as “scanxiety,” which aptly refers to the anxiety or worry patients often feel before undergoing a scan or receiving the results of an examination. Learn tips for reducing anxiety.

Imaging (radiology) tests

Imaging tests create pictures of areas inside your body to help doctors see whether a tumor is present, and if applicable, how far it has spread, and whether a cancer treatment is working without performing surgeries. The images can be produced in several ways, including:

• A CT scan, which can help doctors find cancer and show a tumor’s shape, size, and location. Abdominal CT scans can show evidence of bladder cancer, colorectal cancer, kidney cancer, ovarian cancer, and stomach cancer.
• MRIs, which use strong magnets to make cross-section pictures of your internal organs. An MRI with contrast dye is the best way to see brain and spinal cord tumors and look for signs that cancer may have metastasized (spread) from its origin.
• Nuclear scans, which measure the uptake of radioactive substances injected into the body, can help doctors find tumors and determine the stage of the cancer, as well as decide if treatment is effective later down the line. Types of nuclear scans include:
  • A bone scan, which is used to search for cancers that may have spread from other places to the bones. 
  • Positron emission tomography (PET) scans, which are usually used as a form of radioactive sugar. Body cells consume different amount of sugar based on their growing needs. Cancer cells, which grows quickly, are more likely to take up larger amounts of sugar than normal cells. Patients will be asked not to drink any sugary liquids for several hours before the test. 
• X-rays are good at finding bone problems at a lower cost compared to those of MRI and CT scans. Mammograms are low-dose X-rays that can be used to detect breast cancer. The doctor reviewing your mammogram will be looking for different types of breast changes, such as small white spots called calcifications, abnormal areas called masses, and other suspicious findings that could be signs of cancer.
• Ultrasounds help doctors search for tumors in certain areas of the body that do not appear well on X-rays. Ultrasound images are not as clear as those from CT and MRI scans as they cannot tell whether a tumor is cancerous.

Biopsies

A biopsy is a surgical procedure in which the doctor removes a sample of tissue or cells from the body to determine if they are cancerous. Some biopsies may require a sedative or anesthesia, which can help you relax and stay still. In those cases, especially in the case of general anesthesia, you will feel nothing and likely not even remember any of the procedure.

 The biopsy sample may be obtained in several ways, including:

• With a needle, which a doctor uses to withdraw tissue or fluid. This method is used for bone marrow aspirations, spinal taps, and some breast, prostate, and liver biopsies.
• With an endoscopy, which is a medical procedure where a doctor puts a tube-like camera into the body to look inside. Endoscopes go into natural body openings, such as the mouth or anus. If the doctor sees abnormal tissue during the exam, they will remove the abnormal tissue along with some of the surrounding normal tissues through the endoscope. Endoscopic biopsies are commonly used to look at the inside of the nose, sinuses, throat, lungs, bronchi, the esophagus, stomach, and first part of the intestine, and large intestine.
• With surgery, in which a surgeon removes an area of abnormal cells during an operation. A surgical biopsy can be used to remove a breast lump for a possible breast cancer diagnosis or remove a lymph node for a possible lymphoma diagnosis.

Lab tests

Abnormal levels of certain substances in your body can be an indication of cancer. Lab tests of blood, urine, and other body fluids can be used to confirm a cancer diagnosis of lack thereof. Types of lab tests include: 

• Blood tests, which are used to examine the protein levels inside the blood and check if the abnormal levels are due to cancer-related conditions.
• Urinalysis, which breaks down and analyzes the components of urine to check for the presence of drugs, blood, protein, and substances. Blood in the urine (hematuria) may be the result of a benign (noncancerous) condition such as an infection or other problems. Urinalysis is performed to check for bladder cancer and kidney cancer.
• Tumor marker tests, which are used to check for substances either released by cancer cells into the blood or urine or substances created by the body in response to cancer cells. There are two main types of tumor markers: circulating tumor markers and tumor tissue markers. The first one is used to estimate prognosis, determine the stage of cancer, detect cancer that remains after treatment and assess the performance of a treatment. Tumor tissue markers are used to diagnose, stage, and/or classify cancer, estimate prognosis, and select an appropriate treatment.

Remember: Regular cancer screenings, if they apply to you, can help medical professionals detect cancer when even when no symptoms exist.

About the Medical Reviewer

Dr. Odejide received her medical degree from Howard University. She completed postgraduate training in Internal Medicine at the Brigham and Women's Hospital, followed by a fellowship training in Hematology and Medical Oncology at the Dana-Farber/Partners CancerCare Program. She is currently a member of the DFCI Hematologic Malignancies staff as well as a member of the Division of Population Sciences.