Breast Cancer Tests
There are a host of different tests for breast cancer. Screening tests are those given regularly to apparently healthy individuals to find disease while it's still in more-treatable early stages. Diagnostic tests are given to individuals who have signs or symptoms, in order to establish the presence and severity of a disease. Genetic testing can help determine whether you are at a particularly high risk for the disease.
Besides the monthly self-exam, screening tests women typically undergo on a routine basis are mammography and clinical breast examination, in which a healthcare provider systematically palpates the breasts to detect changes or irregularities. Magnetic resonance imaging, or MRI, may be used as well, although it usually is reserved primarily for women who, because they are carriers of the breast cancer gene, are at very high risk of developing the disease.
Besides being a screening tool, mammography is used to further examine a lump or area of new concern. Also, ultrasound may be used as a complementary study to diagnostic mammography to evaluate a suspicious mass. Once a lump or lesion is confirmed through breast imaging and/or a clinical breast exam, women typically undergo a biopsy, in which tissue is obtained for analysis. This analysis will tell your doctor whether the sampled cells are cancerous or benign.
This section includes information on:
Testing for genetic mutations
Members of some families have genetic mutations that put them at high risk of developing breast cancer. Clues that you may belong to a high-risk family include having had two or more first-degree relatives—mother, sister, or daughter—with the disease, particularly if the relatives were diagnosed before age 50, or having had a male family member with breast cancer. Another indicator is a relative with ovarian cancer, especially if the cancer was not first diagnosed in old age. Women newly diagnosed with cancer who have a family with these disease patterns should think about meeting with a genetic counselor or geneticist to discuss obtaining a blood test to determine whether they carry the BRCA 1 or 2 gene mutation. Similarly, women from families with these cancer patterns who have not had a cancer but are concerned about their risk may wish to consult a genetic counselor or geneticist.
People considering testing should discuss the risks, benefits, and possible psychological impacts before making a decision. Knowing that you have the altered gene may increase your self-monitoring and help you guide family members, but it doesn't tell you whether you will indeed develop breast or ovarian cancer. Some women who learn that they have a mutation choose to have their breasts removed prophylactically. But other options include close surveillance or reducing risk by taking tamoxifen. Meeting with a breast-health expert or genetic counselor can help you fully understand your various options.
Screening tests
These tests look for evidence of disease before a woman notices symptoms or signs. They are key to finding breast cancer while the disease is still in its most treatable stages.
This section includes information on:
Breast self-exam or breast self-awareness
Ask your doctor for advice on the importance of examining your own breasts on a regular basis. The guidelines have changed over the past few years in view of the debate over this technique's effectiveness. The American Cancer Society, for example, now tells women that self-exams are an option as opposed to a monthly necessity. To conduct a self-exam properly, you'll want the advice of a physician or breast specialist on the correct technique. The best time during the menstrual cycle to conduct the exam is one to two weeks after menstruation.
Mammography
This procedure is used both to screen for and diagnose breast cancer. The technique uses low-dose X-rays to produce photographic images, known as mammograms, of breast tissue. Mammography has proved to be the most effective means of detecting cancers early and is credited with a 20 to 30 percent reduction in the death rate from breast cancer.
The special X-ray machines that produce mammograms are equipped with transparent plates that hold and flatten the breasts at the correct angles for making the images. When interpreted by a radiologist, mammograms can reveal suspicious masses plus other changes that cannot be felt or palpated, such as the "microcalcifications" that may accompany DCIS. Though highly effective, mammography does not find every cancer, especially those occurring in highly dense breast tissue common in younger women.
According to the American Cancer Society's guidelines, most women should begin having regular screening mammograms at the age of 40 or the age at which the youngest first-degree relative affected with breast cancer was diagnosed with cancer—whichever comes first. Women should consult with their doctors about whether they should get the test every one or two years, depending on their level of risk.
In addition to screening symptom-free women, "diagnostic mammography" is used to look more closely at new areas of concern.
Other screening procedures
A number of screening techniques may be used in addition to mammography to provide complementary information on the patient or to backstop the radiologist. These include:
- Computer-aided detection: The accuracy of traditional mammography depends in part on breast density as well as the expertise of the radiologist interpreting the image. CAD adds a computer scan as a second look. If the software identifies suspicious areas that the radiologist missed, he or she can go back and re-evaluate.
- Digital mammography: This evolving technique shows mammographic images on a computer display rather than traditional film. This allows the radiologist to manipulate the image—to magnify an area, say, or look at the image in slices—to gain better perspective. The technique also permits the images to be sent electronically to other radiologists or hospital centers. This can be especially helpful when comparing images taken recently with those taken in previous years.
- Magnetic resonance imagery: Because of its ability to reveal small tumors not easily detected on regular mammograms, an MRI may be appropriate for individuals at high risk, especially younger women with dense breasts. Currently, it is not viewed as an appropriate option for women who are not at high risk because it is costly and results in false positives. Further, not all institutions have the capability of biopsying all abnormalities found through MRI.
Diagnostic tests
These tests are ordered when breast cancer is suspected, and if cancer is found, to characterize and stage a cancer.
This section describes:
- Ultrasound
- Biopsies (including the sentinel node biopsy)
- Testing for hormone—estrogen and progesterone—receptors
- Grading a cancer
Ultrasound
This technology employs sound waves to produce images of tissues within the body and is used at both the screening and diagnostic stages to distinguish fluid-filled cysts from solid tumors. It is safe, painless, and has no side effects. Ongoing studies are evaluating whether whole-breast ultrasound should be used in conjunction with mammography to screen high-risk women with dense breast tissue.
Biopsies
If mammography or any other screening method reveals a mass or lesion that a physician believes may be cancerous, a biopsy will be performed to remove a sample of the suspicious tissue. The sample is then sent to a laboratory for examination by a pathologist, who will determine whether it is benign or cancerous.
The tissue sample may be removed by:
- Fine-needle aspiration biopsy: In a procedure resembling a blood draw, a fine, hollow needle is inserted into a lump or lesion and cells are drawn out for evaluation. This is usually performed when a fluid-filled mass is seen on an ultrasound image or your doctor detects a lesion during a clinical breast exam.
- Core needle biopsy: A hollow needle is used to take several rice-grain-size cores of tissue. With this type of biopsy, tissue structure as well as cells can be evaluated. When a solid mass has been detected ultrasound may be used to guide the placement of the needle.
- Stereotactic biopsy: When a suspicious area cannot be located by feel or ultrasound but is visible through mammography, the physician uses a mammogram to locate the area and perform a core needle biopsy.
- Surgical biopsy: All or part of the suspicious tissues may be removed by surgery. Total removal of the tissue is called an excisional biopsy; and partial removal is called an incisional biopsy.
This section also includes a discussion of the sentinel-node biopsy, which is used to gauge whether a cancer has spread to the underarm lymph nodes.
Sentinel node biopsy
One of the first places breast cancer will spread if it is invasive is to the lymph nodes under the arm. Nearly all women with invasive cancer will be advised to have these nodes examined, and some surgeons think it prudent to examine the underarm nodes of women with noninvasive ductal carcinoma in situ (DCIS) as well, especially if it is a high-grade or aggressive form or there is reason to believe that DCIS is distributed throughout the breast.
Until recently, surgeons would remove as many lymph nodes as possible in an axillary (underarm) node dissection. However, this process often caused lymphedema, a numbness and a serious swelling of the arm. The sentinel node biopsy checks for cancer in the first lymph nodes to receive lymph drainage from the breast—the most likely nodes to contain cancer if it has spread. If a sentinel node is removed and found to be healthy, the chance of finding cancer in any of the remaining nodes is very small, and no other nodes need to be removed. When performed by a skilled surgeon, this type of biopsy carries much less risk of lymphedema. Typically, doctors need to have performed about such 30 to 50 surgeries removing the sentinel node and then the rest of the underarm nodes as well, as a check, before they've got the hang of reliably isolating and removing the sentinel nodes. Breast surgeons are more likely to have had the requisite experience than are general surgeons.
To identify the sentinel lymph node or nodes, a surgeon can use one of two "tracers"—materials that are injected in the breast and then flow through the lymph channels into the axillary lymph nodes. One tracer contains a small amount of radioactive material. The surgeon then uses a hand-held Geiger counter to find radioactive lymph nodes. The second tracer is a blue dye, which also flows to the lymph nodes. By following the dye, the surgeon can identify the first lymph nodes reached. At the time of the biopsy, the surgeon will remove any other lymph nodes that feel suspicious.
If a sentinel lymph node is found to contain cancer, a complete axillary dissection typically is done to remove additional lymph nodes under the arm. These nodes also will be examined and if they are found to contain cancer, the chances that the cancer has spread to other parts of the body will be greater. In these situations more aggressive medications or treatment will be recommended.
Testing for hormone receptors
If pathological examination finds breast cells to be malignant, further studies are done to see if the cancer cells have receptors that bind with the hormones estrogen and progesterone. Cancer cells with such receptors are called hormone-receptor positive. Women with receptor-positive cancers are better able to respond to hormonal therapy and thus tend to have a better prognosis.
Grading a cancer
The grade of a cancer indicates the degree of abnormality the cells display. The pathologist makes this determination by examining a sample of tissue removed from the tumor under a microscope and assigning a grade from 1 to 3 based on how closely the cells resemble normal cells in size and shape, how much of the cancer is tubular in structure, and how many of the cells are dividing. The cells in low-grade cancer (grade 1) appear most like normal cells and are very well differentiated. Cells in high-grade (grade 3) cancer have distorted shapes, are poorly differentiated, and tend to grow rapidly. Individuals with tumor cells that are well differentiated tend to have a better prognosis than do those with poorly differentiated tumors.
Breast cancer staging
The stage of a cancer is an expression of the tumor's size and the extent to which it has spread to the lymph nodes and other sites in the body. Stages range from 0 to 4. Staging helps determine treatment options and provides some sense of a patient's overall prognosis. As a general rule, the lower the stage, the better the prognosis.
Breast cancer staging is complicated, and treatment options by stage as well as prognosis are constantly changing, so it is best to review staging information with your doctor.
Stage 0: These cancers are described as noninvasive or in situ (in place). There are abnormal or precancerous cells in the lining of a lobule or duct, but the cells have not spread into normal breast tissue.
Stage I: Cancer cells have spread into tissue beyond the ducts or lobules, although not to the lymph nodes or other parts of the body. The tumor is 2 centimeters (approximately an inch) or less in diameter.
Stage IIA: A tumor has a diameter of 2 centimeters or less and has spread to a small number of lymph nodes, or it is 2 to 5 centimeters in diameter but has not reached the nodes.
Stage IIB: A tumor of 2 to 5 centimeters has spread to the nodes, or a tumor exceeds 5 centimeters in size but has not reached the lymph nodes.
Stage IIIA: Either the tumor's diameter is larger than 5 centimeters or it is smaller than that, but the cancer cells have spread to lymph nodes, and the nodes are sticking to each other or to surrounding tissue.
Stage IIIB: Regardless of the tumor's size, cancer cells have spread out of the breast to the chest wall, the skin, the lymph nodes in the chest wall, or other nearby tissue. There is no evidence of spread to distant sites.
Stage IIIC: Regardless of the tumor's size, cancer cells have spread to lymph nodes under the arm and breastbone or under and above the collarbone. There is no evidence of spread to distant sites.
Stage IV: Regardless of tumor size, cancer cells have reached the lungs, liver, brain, bones, or other sites distant from the breast.
Healthcare professionals also use the following letters when characterizing individual cancers:
- T refers to tumor size
- N (for nodes) refers to the number of lymph nodes with cancer
- M (for metastasis) refers to cancer that has spread to distant sites
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