A recurrence occurs when breast cancer cells reappear after treatment, either in the area around the breast (local or regional recurrence) or in other areas of the body (metastasis). Recurrences are due to cells that have presumably escaped from the original tumor before diagnosis and/or treatment and have become established elsewhere in the body. Cells can travel through the body via either the bloodstream or the lymphatic system. They may remain dormant for years and unknown factors can trigger their subsequent reactivation, resulting in new cancers developing at distant sites.
Recurrence occurs when breast cancer cells reappear after treatment
In order to metastasize, cancer cells have to evade the body’s immune system, make new blood vessels, travel through the bloodstream, figure out what organ to go to, break out of the blood vessel, get into the new organ, and set up a new home. But even when early metastasis has occurred, it doesn’t necessarily spell doom. Let’s say that the cell has successfully made the journey to the lung. Once it arrives, there it has to establish a new home by making new blood vessels. It’s possible that other cells in the lung may be able to keep these invaders under control, but not in every case. The cells then act normally until something happens—a change in the lung’s environment or a new genetic alteration occurs that allows the breast cancer cells to grow in the lung. This might explain why some women will have a recurrence of breast cancer many years after the first diagnosis. Those cells were there from the beginning but were dormant until the right conditions induced them to grow again.
To metastasize, cancer cells have to evade the immune system, and travel to a new area of the body
It was always assumed that recurrences stem from the initial tumor. But studies now have demonstrated that tumors are not composed of just one kind of cell and that a metastases may not be the same type as the original. If you have a recurrence, you should ask about having it biopsied so that it is clear exactly what subtype of breast cancer you now have. Once a recurrence has been diagnosed, the next step is to have a series of tests done to determine whether the cancer is anywhere else in the body. These tests may include a bone scan, chest x-ray, CT scan, liver scan, MRI, PET scan, or blood test. They may also incorporate some blood tests, among which are tests for tumor markers.
To perform a bone scan, a technician injects radioactive particles into your vein, where they are selectively picked up by the bones. After the injection you wait a few hours while the particles travel through the bloodstream; then you go back to the examining room where you are put under a large machine that takes a picture of your skeleton. In the areas where the bone is actively metabolizing (meaning it’s doing something), the radioactive particles will show up much more strongly than in the more inert areas. But that doesn’t mean that what the bone is doing has anything to do with cancer. It could mean there’s arthritis, an infection, or a fracture that is healing. To learn more, an X-ray of the bone is done. Doctors do the bone scan first because they don’t want to expose you to any more radiation than is necessary.
A chest X-ray is done to see if there is cancer in the lungs. This test is done because it is common for breast cancer to metastasize to the lungs.
Computerized tomography (CT) scan
Also known as the CAT scan, the CT scan is an X-ray procedure that produces detailed cross-sectional slices of the body. Instead of taking one picture, like an X-ray does, a CT scanner takes many pictures as it rotates around you. A computer then combines these pictures into an image of a slice of your body. It’s good for detecting brain tumors and cancer in the lungs. It may also be used to detect metastases to the liver.
A liver scan is a test in which a technician injects a diluted radioactive solution into your vein. The radioactive particles are selectively picked up by your liver and will concentrate in areas of heavy activity, as in the presence of rapidly growing cancer cells.
Magnetic resonance imaging (MRI)
MRI uses magnetic energy and radio waves to produce cross-sectional images of the body. Once you have been properly positioned inside the MRI machine, a radio signal is turned on and off. These signals are absorbed by and then echoed out of the body. A computer uses these echoes to create an image of the body.
Positron-emission tomography (PET) scan
PET scans look at how much and how fast glucose is being used by a specific body tissue. All of the tissue in the body—normal tissue and tumor tissue—needs glucose to survive. Cancers are rapidly growing, so they use more glucose than normal tissue. PET scans have been able to detect areas of metastatic disease not seen by other imaging techniques. Before you have the scan done, you will be given a radioactively labeled glucose molecule, called a tracer, which can be taken up and metabolized by your body tissue. It is either injected or inhaled as a gas. Once the tracer enters the body, it travels through the bloodstream to a specific target organ, where it produces gamma rays. A computer analyzes these gamma rays to assess how much and how fast glucose is being used.
The CA 27.29 blood test is the first and only blood test specific to breast cancer. The two other blood tests that oncologists may recommend for women with breast cancer, the CA 15-3 and the CEA, are tumor marker tests used in breast and other cancers. These tests are not good for detecting recurrence, as they cannot find just a small number of cancer cells. They have, however, been found to be useful in following women with metastatic disease, because as breast cancer progresses, the number reported on the tumor marker test will rise. And if your levels are rising, this can help you and your physician make treatment decisions.
Frequently Asked Questions
I’ve completed treatment and my doctor isn’t doing regular tests. Isn't there more we should be doing?
Many people wonder why women are not tested regularly—before symptoms occur—to determine if their cancer has spread.
It seems to go against reason to not do something to try to find metastases early. But the truth is that there is no evidence that any of the tests—PET scans, CT scans, chest X-rays, or blood tests—make any difference in breast cancer survival. Contrary to what most people believe, finding metastatic disease early on does not make it easier to treat or more treatable. That’s because we don’t have treatments that can stop breast cancer once it has spread to other parts of the body. For this to change, we need to develop treatments that can cure cancer after it has spread, and that’s what many researchers are trying to do.
The American Society of Clinical Oncology recommends that women have regular physical exams and mammograms after their breast cancer treatment is completed, but does not recommend routine X-rays, scans, and blood tests unless symptoms are present. Two randomized controlled studies found that none of the screening tests currently used in asymptomatic women with breast cancer provide a survival benefit over waiting for symptoms to develop. So why do doctors do these tests? They give a variety of reasons ranging from “it makes the woman feel better” to “I do it for other cancers, so it is just habit.” But the bottom line is: If a woman learns her cancer has spread through these tests, it only means she will be living longer with the knowledge that she has metastatic disease, not that she will live longer than she would have if she were not diagnosed until symptoms developed.
So while it may seem like your doctor should be doing more, as long as you are having regular physical exams and mammograms, you are doing everything you need to do.
Should I have regular PET scans to look for signs of metastatic disease?
The published research indicates that PET scans can be beneficial to women and their physicians when they are used to monitor a tumor’s response to treatment after metastatic disease has been found. However, there is no evidence that PET scans are valuable in an asymptomatic woman or that having regular PET scans would help women beat cancer. There are two reasons for this:
- The PET scan can only find metastatic disease that is at least two 2cm in size.
- Finding metastatic disease early, or earlier, does not make it more treatable.
It seems to go against reason to not do something to try to find metastases early. But the truth is that there is no evidence that any of the tests—PET scans, CT scans, chest X-rays, or blood tests—make any difference in breast cancer survival. Two randomized controlled studies found that none of the screening tests currently used in asymptomatic women with breast cancer provide a survival benefit over waiting for symptoms to develop. If a woman learns her cancer has spread through these tests, it only means she will be living longer with the knowledge that she has metastatic disease, not that she will live longer than she would have if she were not diagnosed until symptoms developed.
PET scans are probably best used to establish a baseline when there is known metastatic disease to assess and monitor how a tumor is responding to treatment. I agree with the recommendations put out by the American Society of Clinical Oncology and, like them, would not recommend that you have regular PET scans to look for signs of metastatic disease.
What is the CA 27.29 blood test? Should I have it done routinely?
The FDA approved the CA 27.29 blood test in June 1996. It is the first and only blood test that is specific to breast cancer. (The two other blood tests that oncologists may recommend for women with breast cancer, the CA 15-3 and the CEA, are tumor marker tests that are used in breast and other cancers.) The CA 27.29 test measures the level of CA 27.29 antigen, which is found in the blood of breast cancer patients. As breast cancer progresses, the level of CA 27.29 antigen in the blood rises. In theory, by monitoring CA 27.29 test results oncologists can determine if the cancer has spread to other parts of the body, which is called metastasis. [Important point: If breast cancer metastasizes to the liver, it does not mean you have liver cancer. It means you have breast cancer cells in your liver, and the treatment used would be treatment for breast cancer, not treatment for liver cancer.]
Unfortunately, the CA 27.29 test is not as reliable as we initially hoped it would be. In statistical terms, it is neither “specific” nor “sensitive” enough to accurately determine if metastasis has occurred. What does that mean?
If a test for metastasis is highly sensitive, it will be good at finding those women who have metastasis and it will produce very few false negatives (women who are told they have negative results when they really don’t). A test needs to be highly sensitive to rule out disease. In other words, when a test is highly sensitive, if a woman tests negative it means she does not have metastasis.
If a test for metastasis is highly specific, it will be good at finding those women who do not have metastasis and it will produce very few false positives (women who are told they have metastasis when they really don’t). In other words, when a test is highly specific, if a woman tests positive it means that metastasis is indeed present.
Since it is not highly sensitive or specific, the CA 27.29 test can go up for reasons other than metastasis, resulting in false positives, and it may not go up when there is metastasis, resulting in false negatives. The CA 27.29 test has been proven to be helpful in following increases in metastasis in women who have already been found to have metastatic disease, allowing doctors to better adjust treatment regimens.
In addition to having the CA 27.29 test, your oncologist may recommend that you have the CEA and CA 15-3 tumor marker tests done as well. Neither of these tests is highly sensitive nor highly specific either. If you choose to have any of these tests done it should be with the knowledge that there is currently no test or scan that can reliably tell us whether a small number of breast cancer cells have gotten into, and have begun growing in, other parts of the body, and that the information you receive may not be accurate.
Should you have the CA 27.29 test done? The American Society of Clinical Oncology recommends against routine testing of markers after a breast cancer diagnosis. Some oncologists recommend that women have this test every three to six months with the hope that they will find metastasis early. The problem is that there is no evidence that finding metastases by a blood test before a woman has symptoms will improve her survival or quality of life. The treatment of metastatic disease is aimed at reducing symptoms and putting the woman into remission. It is hard to improve symptoms if a woman does not have any. Most women whose breast cancer has metastasized do not show any symptoms until the disease is quite extensive. Symptoms of metastatic disease include bone pain, shortness of breath, lack of appetite and weight loss, and neurological symptoms like pain or weakness or headaches.
There are a series of tests that can help find large amounts of cancer cells in other parts of the body. These are called staging tests (this is not the same as the stages of breast cancer), and include chest X-rays, which can find cancer in the lungs, blood tests that can determine if the cancer has spread to the liver, and bone scans, which can help ascertain if the cancer has spread to the bone. CT scans are also used to detect the spread of cancer to the liver, the lungs, a certain area of bone, or even your brain. Like the blood tests, though, these tests are not good at finding small numbers of cancer cells.
Ultimately, the only way to determine whether having routine CA 27.29 testing is right for you is to think about how you want to handle the aftermath of your breast cancer treatment and whether a test that has limitations will be helpful for you. Some women find reassurance in having the CA 27.29 test done; others find the thought of having the test stressful and choose to not have it done. There is no “right” choice. If you do decide to have the test done, here are a few things you should know:
- A normal CA 27.29 level is usually less than 38 to 40 U/ml (units/milliliter), depending on where the lab test is done.
- Because anything under 40 is considered normal, you shouldn’t worry if it’s 20 one time and then 30 another time.
- Just because the test result is higher than 40 it doesn’t mean your cancer has spread. Endometriosis, ovarian cysts, first-trimester pregnancy, benign breast disease, and kidney and liver disease are just some of the noncancerous conditions that can raise your CA 27.29 level.