Tests to Diagnose Cancer
An early diagnosis gives you the best chance for a cure. You’ll probably need a variety of tests to determine if you have cancer.
No single test is available to diagnose cancer. Your doctor may use several approaches to check for different forms of the disease.
Getting an accurate diagnosis is important because it can help you and your physician come up with an effective treatment strategy. It can also rule out other conditions and reveal the stage of your disease.
Typically, your healthcare provider will perform a complete physical exam, ask about family history, and recommend further testing if cancer is suspected.
Types of Tests
Biopsy
In a biopsy, doctors remove a small piece of tissue and examine it under a microscope. Normal cells will look uniform, and cancer cells will appear disorganized and irregular.
Most of the time, a biopsy is needed to know for sure if you have cancer. It’s considered the only definitive way to make a diagnosis for most cancers.
Biopsies can be performed in different ways, such as:
- Needle Biopsy A needle is used to remove tissue or fluid.
- Endoscopic Biopsy With this method, your doctor uses a special lighted tube, called an endoscope, to look at areas inside your body. Then, cells or tissues can be removed through the tube.
- Surgical Biopsy Surgeons remove part or all of a tumor during a surgical procedure.
- Skin Biopsy With this procedure, your doctor cuts off a small sample of your skin to analyze it.
- Liquid Biopsy You may soon hear more about this form of testing because it is new and is increasingly being used by clinicians. A liquid biopsy is a blood test that scans for traces of markers for certain cancers or individual tumor cells in the blood. This is often done when it is difficult to safely biopsy the tumor because of its location.
Biopsies are sometimes done with the help of imaging technology to locate suspicious spots.
The type of biopsy procedure you need will depend on your type of cancer and where it’s located.
RELATED: Blood Test Can Accurately Detect Early-Stage Lung Cancer
Lab Tests
Blood and urine tests may help your doctor detect abnormalities that could signal cancer. For example, people with leukemia often have an unusual number or type of white blood cells that show up on a blood test.
Your doctor may also recommend a lab test to check for genetic mutations, or changes, that increase your risk for certain cancers.
Typically, lab tests alone aren’t used to diagnose cancer. You’ll probably need another type of exam to confirm that it’s cancer.
Imaging Tests
Imaging tests can help doctors see inside your body and look for a tumor or areas where cancer is present. Some common types include:
- Computed Tomography (CT) Scan A CT scan takes detailed images of your organs with an X-ray machine that’s hooked up to a computer. You might receive dyes through an intravenous (IV) catheter, or oral or rectal contrast materials to help doctors see certain areas in your body better.
- Ultrasound An ultrasound uses sound waves to create pictures of regions in your body.
- Magnetic Resonance Imaging (MRI) An MRI uses powerful magnets and a computer to capture images of the inside of your body.
- Nuclear Scan With a nuclear scan, you receive an injection of radioactive material that collects in certain organs or bones. A scanner spots and measures radioactivity and creates images of organs on a computer screen or film.
- Positron Emission Tomography (PET) Scan A PET scan is a type of nuclear scan. The most common type of PET scan is an FDG PET scan, which uses a special radioactive type of sugar. This sugar then goes to the parts of your body that use the most energy, including your brain, your heart, and fast-growing cells such as those in a tumor. This can tell your doctor if your tumor has spread to another part of your body.
- X-ray In an X-ray, low doses of radiation help create pictures of the inside of your body.
Endoscopic Exam
Sometimes, endoscopic exams can be used to find cancer. These procedures allow doctors to see inside your body with the help of an endoscope camera. Common types of endoscopies include colonoscopy, sigmoidoscopy, and cystoscopy.
Physical Exam
Your doctor might perform a physical exam to check for lumps, enlarged organs, or other signs that could indicate you have cancer. This is often the first type of exam that’s performed. You will need further testing if your physician thinks you might have cancer after a physical exam.
Other Tests
Your doctor may suggest several other tests, depending on what kind of cancer is suspected. For instance, your physician might want you to take a pulmonary breathing test if he thinks you have lung cancer.
RELATED: Is It Lung Cancer? What Tests Will I Get?
Can Cancer Be Diagnosed Without a Biopsy?
Liquid biopsies, which are performed via a simple blood test, offer a promising role in cancer detection. They have the potential to diagnose cancer and identify molecular traits in a person’s tumor. But there are still some problems to work out.
For one thing, studies need to confirm that detecting circulating DNA in a person’s blood can be a precise marker for diagnosing early-stage cancer.
While some research has shown liquid biopsies can find cancer-specific DNA in more than 85 percent of patients with advanced cancers, others have found the tests produced false positives and weren’t able to correctly identify the type of cancer. (1,2)
Right now, liquid biopsies are used along with traditional biopsies and aren’t considered a first-line approach.
But scientists are hopeful that advances in technology could lead to a noninvasive cancer blood screening test in the near future. (2,3)
What Happens After I Get a Diagnosis?
Once you get a cancer diagnosis, you and your doctor can come up with a treatment strategy. Your healthcare provider will also stage your cancer, which can give you a better idea of how to approach it.
A cancer diagnosis is scary, but the information you learn from diagnostic tests is helpful for planning your long-term treatment approach. The earlier on in your disease that you get diagnosed and treated, the better your outlook.
Should You Get Your Tumor Tested?
If you’ve been diagnosed with cancer, you may consider tumor DNA sequencing. This procedure, sometimes called genetic testing or genetic profiling, helps pinpoint unique DNA changes in a tumor.
Sometimes, identifying a genetic mutation in your cancer can help your doctor personalize your treatment plan. For example, certain medicines, especially targeted therapies, are only successful for people with specific gene alterations.
A tumor DNA sequencing test is usually done by sending a sample of your tumor to a lab.
This type of testing is often recommended for people with lung cancer, colorectal cancer, and melanoma. There are new drug approvals for patients with certain rare mutations, regardless of the type of cancer you have, so it may prove beneficial for all cancer types, especially if a patient’s cancer is metastatic or still progressing after their first type of therapy.
The tests don’t benefit everyone with cancer, so you should talk to your doctor about the pros and cons. (4)
Additionally, testing of particular tumor markers might be recommended for certain cancer types. For instance, those with breast cancer might get tests for estrogen levels, progesterone levels, and the HER2 receptor, and those with lung cancer might get tests for the PDL-1 protein. These tests are used to determine which treatments are best to manage patients’ cancer.
Ways to Cope With a Cancer Diagnosis
You might feel scared, overwhelmed, or depressed after receiving a cancer diagnosis. These are all normal feelings. Here are some ways to cope.
- Learn about your cancer. Ask your doctor about your disease, treatment options, and prognosis. The more you know, the more confident you’ll be when it comes to making decisions about your treatment.
- Lean on family and friends. Keep your family and friends close. You might need someone to drive you to doctor’s appointments or even perform simple tasks like grocery shopping. Just having someone to talk to can also help you cope during this difficult time. If you don’t have close family members or friends, you can join an online support group. Organizations such as the American Cancer Society and the National Cancer Institute offer helpful information about finding support groups.
- Look for a patient navigator. Some hospitals and organizations have trained professionals who can help you navigate through your cancer journey. These guides can assist you with medical, legal, and financial matters.
- Stay healthy. Try to eat a healthy diet, exercise daily, and get enough rest. These simple habits can give you more energy and prepare your body for cancer treatments.
Editorial Sources and Fact-Checking
- A New Approach to Cancer Diagnosis. Harvard Health. March 1, 2018.
- Liquid Biopsies: Past, Present, and Future. American Cancer Society. February 12, 2018.
- Liquid Biopsy: Using DNA in Blood to Detect, Track, and Treat Cancer. National Cancer Institute. November 8, 2017.
- Biomarker Testing for Cancer Treatment. National Cancer Institute. December 14, 2021.
Additional Sources
- ACS Patient Programs and Services. American Cancer Society.
- Cancer Support Groups. National Cancer Institute. January 24, 2019.