Diagnosis of breast cancer

Diagnosis is the process of finding out the cause of a health problem. Diagnosing breast cancer usually begins when you find a lump in your breast or a screening mammography suggests a problem with the breast. Your doctor will ask you about any symptoms you have and do a physical exam. Based on this information, your doctor may refer you to a specialist or order tests to check for breast cancer or other health problems.

The process of diagnosis may seem long and frustrating. It’s normal to worry, but try to remember that other health conditions can cause similar symptoms as breast cancer. It’s important for the healthcare team to rule out other reasons for a health problem before making a diagnosis of breast cancer.

The following tests are usually used to rule out or diagnose breast cancer. Many of the same tests used to diagnose cancer are used to find out the stage (how far the cancer has progressed). Your doctor may also order other tests to check your general health and to help plan your treatment.

Health history and physical exam

Your health history is a record of your symptoms, risk factors and all the medical events and problems you have had in the past. Your doctor will ask questions about your history of:

  • symptoms that suggest breast cancer
  • breast disease or breast cancer
  • taking hormone replacement therapy (HRT)
  • radiation to the chest
  • other cancers that increase the risk for breast cancer, including ovarian or colorectal cancer

Your doctor may also ask about a family history of:

  • breast cancer
  • risk factors for breast cancer
  • other cancers that increase the risk for breast cancer, including ovarian or colorectal cancer

A physical exam allows your doctor to look for any signs of breast cancer. During a physical exam, your doctor may:

  • do a clinical breast exam to check your breasts and armpits for lumps, thick or hard areas and changes to the skin or nipples
  • feel the abdomen to find out if the liver is larger than normal, or enlarged
  • listen to the lungs

Find out more about physical exams and clinical breast exams.

Diagnostic mammography

Diagnostic mammography is an x-ray that uses small doses of radiation to make an image of the breast. It is used to follow up on abnormal results of a screening mammography or a clinical breast exam. Mammography can also be used to find an abnormal area during a biopsy.

Find out more about a mammography.


An ultrasound uses high-frequency sound waves to make images of parts of the body. It is used to find out if a breast lump is a solid tumour or a cyst. Doctors may also use ultrasound to guide them to the area to be tested during a biopsy.

Women with advanced breast cancer may have an ultrasound to check if the cancer has spread to the liver (called liver metastasis).

Find out more about ultrasounds.


A biopsy is the only definite way to diagnose breast cancer. During a biopsy, the doctor removes tissues or cells from the body so they can be tested in a lab. A report from the pathologist will confirm whether or not cancer cells are found in the sample.

The type of biopsy done will depend on if the lump is palpable, which means that you can feel it, or non-palpable, which means you can’t feel it. The doctor may use mammography or ultrasound to help them find the area to be tested. Most biopsies are done in a hospital, and you can go home when the biopsy is finished.

Fine needle aspiration(FNA) uses a very thin needle and syringe to remove a small amount of tissue from a lump. Doctors use it to find out if the lump is a cyst or solid tumour. FNA cannot tell doctors if the cancer is non-invasive or invasive. Find out more about fine needle aspirations (FNAs).

Core biopsy uses a special hollow needle to remove tissue from the body. Doctors use it to take a sample from a suspicious area in the breast. They may take several samples of the area during the procedure. Sometimes doctors use a special vacuum to remove more tissue through the hollow needle. This technique is called vacuum-assisted core biopsy. Find out more about core biopsies.

Stereotactic core biopsy uses 3-D, or stereotactic, images to find the exact location of a tumour or suspicious area in the breast. Doctors use these images to guide them during a core biopsy. Stereotactic core biopsy is used to take samples from lumps that can be seen on an imaging test but that can’t be felt in the breast. Find out more about stereotactic core biopsies.

Wire localization biopsy uses mammography to place a fine wire into a suspicious area in the breast that can’t be felt. The wire is left in place to guide the surgeon to the area during a surgical biopsy. Find out more about wire localization biopsies.

Surgical, or open, biopsy removes all or part of a lump or a suspicious area. An excisional biopsy removes the whole area with a margin of healthy tissue around it. An incisional biopsy removes only part of the area. Find out more about surgical biopsies.

Punch biopsy uses a sharp hollow cutting instrument to remove an area of skin and the underlying tissue. It is used to diagnose inflammatory breast cancer, which means there are cancer cells in the lymph vessels of the skin. Find out more about punch biopsies.

Lymph node biopsy

A lymph node biopsy is a surgical procedure that removes lymph nodes so they can be examined under a microscope to find out if they contain cancer.

Breast cancer cells can break away from the tumour and travel through the lymphatic system. The first place they may spread is the lymph nodes under the arm (called the axillary lymph nodes). Doctors use the number of lymph nodes that have cancer in them to help determine the stage of breast cancer.

Sentinel lymph node biopsy (SLNB) is used to identify and remove the sentinel node to see if it contains cancer cells. The sentinel node is the first lymph node in a chain or cluster of lymph nodes that receives lymph fluid from around a tumour. Doctors will remove other lymph nodes only if the sentinel node has cancer in it. It is offered if the breast tumour is smaller than 5 cm and the axillary lymph nodes can’t be felt during a physical exam. Find out more about sentinel lymph node biopsies.

Axillary lymph node dissection (ALND) removes lymph nodes from under the arm. ALND is the standard way doctors check lymph nodes in most centres in Canada. Find out more about axillary lymph node dissections (ALNDs).

Hormone receptor status testing

Estrogen and progesterone are hormones that can stimulate the growth of breast cancer cells. Hormone receptor status testing looks for estrogen receptors (ERs) and progesterone receptors (PRs) in the breast cancer cells. This information will help your healthcare team decide which treatments will work best for you.

Find out more about hormone receptor status testing.

HER2 status testing

ERBB2 is more commonly known as HER2 (or HER2/neu). HER2 stands for human epidermal growth factor receptor 2. It is a gene that has changed (mutated), so it helps a tumour grow (called an oncogene).

HER2 status testing is done to find out if breast cancer cells are making more HER2 protein than normal (called overexpression). This information will help your healthcare team decide which treatments will work best for you.

Find out more about HER2 status testing.

Complete blood count (CBC)

A CBC measures the number and quality of white blood cells, red blood cells and platelets. A CBC is done to check your general health. Your healthcare team also uses a CBC as a baseline that they can check against future blood counts taken during and after treatment.

Find out more about a complete blood count (CBC).

Blood chemistry tests

Blood chemistry tests measure certain chemicals in the blood. They show how well certain organs are functioning and can help find abnormalities. Blood chemistry tests used to stage breast cancer include the following.

Blood urea nitrogen (BUN) and creatinine may be measured to check how well the kidneys are working. The healthcare team will check kidney function before chemotherapy is given and may check it again during or after treatment.

Alanine aminotransferase (ALT) and aspartate transaminase (AST) may be measured to check liver function. Higher than normal levels of these enzymes could mean that cancer has spread to the liver.

Alkaline phosphatase can be used to check liver function or if there is cancer in the bone. Higher than normal levels of this enzyme could mean that cancer has spread to the liver or the bone.

Find out more about blood chemistry tests.

Tumour marker tests

Tumour markers are substances found in the blood, tissues or fluids removed from the body.

The healthcare team will measure tumour markers in women who have advanced or metastatic breast cancer when they are first diagnosed. They use the levels of the following tumour markers to check response to treatment:

  • cancer antigen 15-3 (CA15-3)
  • carcinoembryonic antigen (CEA)

Find about more about tumour marker tests.


An x-ray uses small doses of radiation to make an image of parts of the body on film. It is used to find out if breast cancer has spread to the lungs.

Find out more about x-rays.

Bone scan

A bone scan uses bone-seeking radioactive materials (called radiopharmaceuticals) and a computer to create a picture of the bones. It is used to find out if breast cancer has spread to the bones (called bone metastasis).

A bone scan is done if a woman has bone pain or the level of alkaline phosphatase is higher than normal. Doctors may also order a bone scan if a breast tumour is larger than 5 cm or they can feel lymph nodes under the arm (called axillary lymph nodes). They do not do bone scans for women with stage I breast cancer.

Find out more about bone scans.


Magnetic resonance imaging (MRI) uses powerful magnetic forces and radiofrequency waves to make cross-sectional images of organs, tissues, bones and blood vessels. A computer turns the images into 3-D pictures.

An MRI is not used routinely to diagnose breast cancer. Doctors may use an MRI to better examine an abnormality found on mammography if they can’t find it with other tests or if results from other tests are not clear.

Find out more about MRIs.


Scintimammography uses a radioactive material (called a radioactive isotope) and a special camera to take pictures of the breast. It may be used to look at breast abnormalities after mammography, especially if there is scarring or dense tissues in the breast.

Find out more about a scintimammography.


Ductography is a special type of x-ray that looks at the breast ducts. It is sometimes used to find out what is causing nipple discharge. It is also used to help diagnose an intraductal papilloma, which is a non-cancerous tumour that can cause nipple discharge.

Questions to ask your healthcare team

To make the decisions that are right for you, ask your healthcare team questions about a diagnosis.

Expert review and references

  • American Cancer Society. Breast Cancer. 2015: https://www.cancer.org/.
  • Morrow M, Burstein HJ, and Harris JR . Malignant tumors of the breast. DeVita VT Jr, Lawrence TS, & Rosenberg SA. Cancer: Principles and Practice of Oncology. 10th ed. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins; 2015: 79: 1117-1156.
  • National Cancer Institute. Breast Cancer Treatment for Health Professionals (PDQ®). 2015.
  • National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Breast Cancer (Version 2.2015). http://www.nccn.org/professionals/physician_gls/f_guidelines.asp.

Medical disclaimer

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