What Tests Are Performed to Help Diagnose Mesothelioma
Some people who have had cancer, whether they are currently living with the disease or whether it is in remission, can point to a moment that separates the “before time” from the present. Perhaps it was when they visited the doctor after suffering for months from nonspecific symptoms such as fatigue, lack of appetite, and a persistent, dry cough. Maybe it was when they got a routine blood test, mammogram, or colonoscopy, and instead of just getting a notification that their lab tests were ready for viewing on the doctor’s office’s online portal, they got a phone call asking them to come back to the office that same week. Others might say that the moment that everything changed was when the doctor told them the results of the tissue biopsy. All of this goes to show that, despite the many medical advances of recent decades, it is still not possible for doctors to diagnose cancer in a single moment. Weeks of tests lead to the tissue biopsy by which they can be sure that the cause of your symptoms is cancer, and after that, they must do even more tests to decide on the most appropriate course of treatment. These are some of the tests that you can expect to undergo if your doctor suspects that you have mesothelioma or another kind of cancer.
Only Tissue Biopsies Can Give a Definite Diagnosis
Even if you seem like a textbook case of mesothelioma, with a history of occupational exposure to mesothelioma, symptoms like cough and shortness of breath, and a chest X-ray that shows abnormal growths and fluid buildup, your doctor cannot be sure that it is mesothelioma as opposed to some other disease until after they perform a tissue biopsy. The tissue biopsy involves surgically removing cells from your chest (or wherever the site of the abnormal growth is) and analyzing them under the microscope. The tissue biopsy will show whether the cells are benign or cancerous. If they are cancerous, it will show what kind of cancer they are. Mesothelioma and lung cancer are two different kinds of cancer, even though they occur in similar areas of the body.
There are various ways to perform a tissue biopsy on cells from the chest; some of these are minimally invasive, and others involve open surgery. In order to tell where the cells are, and therefore the easiest and least traumatic way to access them, your doctor must first do diagnostic imaging tests such as X-rays, CT scans, MRIs, and PET scans.
What Chest X-Rays Can and Cannot Do
An X-ray image, also known as a radiograph, uses electromagnetic radiation to visualize the inside of the body as a two-dimensional image in black and white. Most people usually think of X-rays in the context of them providing images of bones, but diagnosing bone fractures is only one of the applications of radiography. A chest X-ray shows a lot more than just the location of the ribs, sternum, and spine and whether they show any signs of injury.
If your symptoms and medical history indicate an elevated risk of mesothelioma, a chest X-ray is one of the tests your doctor will order. The chest X-rays of patients with mesothelioma often show nodules of abnormal cells on the lining of the chest wall or on the outside of the lungs; they might also show scar tissue or excessive fluid buildup in the chest cavity. If your chest X-ray shows these abnormalities, your doctor might order a biopsy of cells from the tumor or from fluid removed from your chest cavity through needle aspiration.
Chest X-rays have two major limitations when it comes to diagnosing mesothelioma. The first is that the image is two-dimensional; the X-ray can show you the height and width of the abnormal growth, but not its depth. The other limitation is that an X-ray can only tell you where the abnormal nodules are and roughly how big they are, but it cannot tell you what kind of cells they contain and therefore whether or not they are cancerous.
CT Scans, PET Scans, and MRIs
If the chest X-ray shows that tumors or other abnormal growths are present, the next step is to order other diagnostic imaging tests that can visualize the abnormalities in more detail. The most common types of these imaging tests are CT scans, PET scans, and MRIs.
- The CT in CT scan stands for computerized tomography; these are also sometimes called CAT scans, which stands for computerized axial tomography. In order to make your internal organs visible on the CT scan, you will first get an intravenous (IV) injection of dye. A CT scan photographs your chest cavity from many angles, enabling the radiologist to evaluate a three-dimensional image of the area. If tumors are present, a CT scan gives a more accurate assessment of their size than a two-dimensional X-ray does. A CT scan can also show whether the lymph nodes in your chest cavity are enlarged. Lymph nodes, also known as lymph glands, store white blood cells called lymphocytes and transport fluid throughout the body. Of course, this finding is not enough to make a diagnosis definitively. The lymph nodes nearest to a cancerous tumor are usually the first place that cancer spreads, and if this has happened, the lymph nodes will appear enlarged on the CT scan. Of course, lymph nodes can also become enlarged for reasons unrelated to cancer, such as infections. A CT scan can also tell you how close the tumor is to the heart, diaphragm, and other body parts; this can help doctors make decisions about treatment, such as whether to choose surgery, chemotherapy or both.
- MRI stands for magnetic resonance imaging. This test uses radio waves and magnets connected to a computer to generate images. MRI is very effective at visualizing the brain, joints, and insides of bones. Therefore, the test is only used in cases of mesothelioma if cancer has spread beyond the pleurae or peritoneum.
- PET stands for positron emission tomography. This test measures which structures in the body are using more glucose than others, and it makes those structures appear brighter on the image than the surrounding tissues. Tumors and cancer cells appear as bright “hot spots” on a PET scan, which is why this test is especially useful for monitoring the disease progression of mesothelioma. Inflamed tissues that do not contain cancer cells also appear as hot spots, which is why neither PET scans nor any kind of imaging tests is enough, on their own, to yield a mesothelioma diagnosis.
What About Blood Tests?
In the weeks leading up to a mesothelioma diagnosis, or even after you begin treatment, it might seem like you are constantly going to the doctor’s office or lab for more blood tests. If blood tests cannot diagnose cancer, then why does your doctor keep ordering so many of them? These tests can help doctors confirm the findings they see on images, to support the case for doing tissue biopsies, which require surgery.
Your doctor might test the level of your red blood cells, white blood cells, and platelets. Cancers and medications used to treat them can affect the levels of all of these types of blood cells. Certain types of cancers also lead to elevated levels of compounds called tumor markers or biomarkers; these can be proteins, peptides, or carbohydrates. If your blood tests show elevated levels of the tumor markers most closely associated with mesothelioma, your doctor will order diagnostic images, a tissue biopsy, or both. Tumor markers also are not enough to count as a cancer diagnosis on your own. For example, elevated levels of mesothelin can indicate mesothelioma, but they can also indicate ovarian cancer or lung cancer.
Tests to Monitor the Progress of Treatment
Once you get a mesothelioma diagnosis after what seems like an endless series of tests, the testing is not over. The doctor will need to do more tests, including bloodwork and imaging, to see whether the cancer has spread to any other parts of the body besides the pleurae or peritoneum where it was first diagnosed. Seeing how far the disease has progressed is known as staging; this is what it means when someone has stage 1, stage 2, or some other stage of cancer. PET scans are especially useful in the staging process.
Once you begin treatment with chemotherapy or immunotherapy, you will need frequent blood tests to determine how well the treatment is working and whether your side effects are well managed. Your doctor may test your red blood cells and white cells to see where you are anemic or dangerously immunosuppressed. You might also get blood tests to measure the level of tumor markers; if they decrease, it means that the tumor is shrinking because you are responding well to treatment. After surgery, tests for tumor markers can be among the tests to determine whether you also need chemotherapy. Even if your cancer has gone into remission, you will still get tested every few months to see whether you are still in