Diagnosis

Doctors use many tests to diagnose cancer and determine if it has metastasized. Some tests may also determine which treatments may be the most effective. For most types of cancer, a biopsy is the only way to make a definitive diagnosis of cancer. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis. Imaging tests may be used to find out whether the cancer has metastasized. Your doctor may consider these factors when choosing a diagnostic test:

• Age and medical condition
  
  
• The type of cancer suspected
  
  
• Severity of symptoms
  
  
• Previous test results

In addition to a physical examination, the following tests may be used to diagnose metaplastic carcinoma of the breast:

Imaging tests

Diagnostic mammography. Diagnostic mammography is similar to screening mammography except that more views (pictures) of the breast are taken, and it is often used when a woman is experiencing signs, such as nipple discharge or a new lump. Diagnostic mammography may also be used if something suspicious is found on a screening mammogram.

Ultrasound. An ultrasound uses high-frequency sound waves to create an image of the breast tissue. An ultrasound may distinguish between a solid mass, which may be cancer, and a fluid-filled cyst, which is usually not cancer.

MRI. An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. A contrast medium (a special dye) may be injected into a patient’s vein to create a clearer picture. An MRI may be used once a woman has been diagnosed with cancer to check the other breast for cancer, but the benefit of this is controversial. It may also be used for screening. According to the ACS, women at high risk for breast cancer (for example, women with BRCA gene mutations or a strong family history of breast cancer) should receive MRI screening along with a mammogram. MRI may often be better at seeing a small mass within a woman’s breast than a mammogram or ultrasound, especially for women with very dense breast tissue, but has a higher rate of false-positive test results (a test result that indicates cancer when there is no cancer present) and may result in more biopsies. In addition, an MRI does not show calcifications, which could indicate in situ breast cancer. Talk with your doctor for more information.

Surgical tests

Biopsy. A biopsy is the removal of a small amount of tissue for examination under a microscope. Other tests can suggest that cancer is present, but only a biopsy can make a definite diagnosis. The sample removed from the biopsy is analyzed by a pathologist (a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease).

• Image guided biopsy is used when a distinct lump can't be felt. It can be done with a fine needle aspiration biopsy (FNAB, uses a small needle to remove the tissue sample), stereotactic core biopsy (uses x-rays to find the area of tissue to be removed), or a vacuum-assisted biopsy (uses a thicker needle to remove multiple large cores of tissue). During this procedure, a needle is guided to the area of concern with the help of mammography, ultrasound, or MRI. A small metal clip may be put into the breast to mark the site of biopsy, in case the sample tissue proves cancerous and additional surgery is required. An advantage of this technique is that a patient may only need one operation for treatment or staging.
  
  
• Core biopsy can obtain tissue or FNAB can obtain cells in masses that can be felt, and these can then be analyzed for the presence of malignant (cancerous) cells.
  
  
• Surgical biopsy removes the largest amount of tissue. This biopsy may be incisional (removal of part of the lump) or excisional (removal of the entire lump).

If cancer is diagnosed, a second surgery may be needed to get a clear margin (area of tissue around the tumor where there are no cancer cells) and/or remove lymph nodes.

Doctors may also test the tissue from a biopsy to help guide treatment decisions. The tests include:

• Tumor features. Examination of the tumor under the microscope determines if it is invasive or in situ; grade (how different the cancer cells look from healthy cells); and whether the cancer has spread to the blood vessels or lymph vessels. The margins of the tumor are also examined.
  
  
• Estrogen receptor (ER), progesterone receptor (PR), and HER2 tests. Because the cells that become metaplastic breast cancer are not part of the breast gland, metaplastic breast cancer is always ER-negative, PR-negative, and HER2-negative.
  
  
• Genetic description of the tumor. Tests that look at the biology of the tumor are becoming more common to understand more about breast cancer.

Blood tests

The doctor may also need to do blood tests to learn more about the cancer.

Complete blood count (CBC). CBC is a blood test done to determine the following:

• Hemoglobin level (a measure of the number of oxygen-carrying cells)
  
  
• Hematocrit level (the percentage of red blood cells in whole blood)
  
  
• The number of white blood cells (cells that help to fight infection)
  
  
• The number of platelets (cells that help blood to clot as necessary)
  
  
• Differential (the percentage of several types of white blood cells)

Alkaline phosphatase levels. High levels of this enzyme could indicate the disease has spread to the liver, bone, or bile ducts.

Total bilirubin count, serum glutamic-oxaloacetic transaminase (SGOT), and serum glutamate pyruvate transaminase (SGPT) levels. These tests evaluate liver function. High levels of any of these substances can indicate liver damage, a signal of possible spread to that organ.

Tumor marker tests. A tumor marker (also called a serum marker or biomarker) is a substance found in a person's blood, urine, or body tissue. The presence of a tumor marker, or having higher or lower than normal levels of a tumor marker, may indicate an abnormal process in the body, which could be because of cancer or a noncancerous condition. Tumor markers may be used for diagnosis, treatment planning, and/or treatment monitoring. For more information, read the Tumor Markers for Breast Cancer.

Additional tests

The doctor may order additional tests (depending on the individual’s medical history and results of the physical examination) to evaluate the stage of the cancer. Read the Staging section for more information. These tests are not recommended for all patients.

• A chest x-ray may be used to look for cancer that has spread from the breast to the lung.
  
  
• A bone scan may be used to look for spread to the bones. A bone scan uses a radioactive tracer to look at the inside of the bones. The tracer is injected into a patient’s vein. It collects in areas of the bone and is detected by a special camera. Healthy bone appears gray to the camera, and areas of injury, such as those caused by cancer, appear dark.
  
  
• A computed tomography (CT or CAT) scan may be used to look for distant tumors. A CT scan creates a three-dimensional picture of the inside of the body with an x-ray machine. A computer combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. Sometimes, a contrast medium is injected into a patient’s vein to provide better detail.
  
  
• A positron emission tomography (PET) scan may be used to determine whether the cancer has spread. A PET scan is a way to create pictures of organs and tissues inside the body. A small amount of a radioactive substance is injected into a patient’s body and absorbed by the organs or tissues being studied. This substance gives off energy that is detected by a scanner, which produces the images.

To learn more about what to expect during common diagnostic tests, read Cancer.Net: Tests and Procedures.

To learn about the terms used in this section, read the Cancer.Net Feature: Cancer Terms to Know: Newly Diagnosed.