When a growth is found on the breast tissue or some other symptom of breast cancer manifests, then going for a mammogram or a clinical breast examination is essential in determining whether or not a patient has breast cancer. Changes in the size and shape of breasts are natural and occur throughout a person’s lifetime – those changes do not equal a breast cancer diagnosis. More information is needed before a final diagnosis can be made.

Diagnosis is required for women who (via Quebec Breast Cancer Foundation):

  • Show signs of breast cancer;
  • Are suspected of having breast cancer after their doctor speaks to them and performs a clinical examination of their breasts;
  • Have had a screening mammogram that appears to indicate a problem with either or both breasts.

Your doctor will perform a variety of tests to confirm a definitive prognosis. The types of diagnostic tests the doctor will use are dependent on the patient.

The various diagnostic methods are categorized in two types (via Canadian Breast Cancer Foundation):

Diagnostic imaging. The two most common practices your doctor will use are diagnostic mammography and a breast ultrasound. These tests are usually the primary steps the doctor will use to determine whether or not a patient has breast cancer.

Biopsy. Following diagnostic imaging, if the doctor isn’t confident a tissue is cancerous or benign; the doctor will perform a biopsy. This procedure removes a sample of breast cells or tissue to be checked in a lab for signs of cancer. This procedure may be the only way to be certain a breast problem is indeed breast cancer.

Diagnostic Imaging

Medical diagnostic imaging is the technique and process of creating visual representations of the interior of a body for clinical analysis and medical intervention. Medical imaging seeks to reveal internal structures hidden by the skin and bones, as well as to diagnose and treat disease (via breast-cancer.ca).

Diagnostic Mammography

The difference between screening and diagnostic mammography is that screening mammography looks for signs of cancer and diagnostic mammography investigates possible problems. A woman with a breast problem (for instance, a lump or nipple discharge) or an abnormal area found in a screening mammogram typically gets a diagnostic mammogram (via Canadian Cancer Society).

Diagnostic mammography uses a low-dose X-ray of the breasts to get a detailed picture of any breast changes. This method of diagnostic imaging is more thorough and takes a little longer than a screening mammography. It provides more detailed images and views of the breast taken from different angles.

Diagnostic mammography is usually done on both breasts so that doctors can compare the breast tissue (via Canadian Cancer Society). The procedure takes about 10-20 minutes for the test to be completed (via Nova Scotia Health Authority). The possible effect of mammographic radiation on the fetus means that mammography should be avoided during pregnancy (via breast-cancer.ca).

For more information on mammography, click here.

Breast Ultrasound

Breast ultrasounds or sonography is often used for a “second look”, a follow-up application, or to determine if the lump is a solid tumour or a fluid-filled cyst. Ultrasounds are also used to visually guide a health care practitioner for other procedures such as biopsies (via Canadian Breast Cancer Foundation). A gel is spread on your skin in the area being examined and a small handheld instrument is passed over the area to form an image called a sonogram. The device sends out harmless sound waves and the reflected sound waves form a picture of your internal structure.

There is no radiation involved, which makes it the preferred diagnostic method of diagnostic imaging for pregnant women. Women with highly dense breasts are often screened with ultrasound because mammograms of women with dense breast tissue tend to be hard to interpret (via breast-cancer.ca). The test could be performed in a doctor’s office, a clinic, or in a hospital as an outpatient procedure. The test usually takes between 15 and 30 minutes, but could take longer. In general, after having a breast ultrasound, you can go back to your daily activities right away, as no anesthesia is required and the test causes no side effects or pain (via Quebec Breast Cancer Foundation).

For more information about breast ultrasounds, click here.

Other Imaging Techniques

Besides breast ultrasound, there are other techniques for imaging breast tumours, providing information on their progression and in particular, on whether the cancer has spread to other parts of the body. Most of these tests do not require anesthetic and are painless.

X-rays can be used, of course, as well as a wide range of techniques such as computerized axial tomography (CAT scans), ductography, breast scintigraphy, magnetic resonance imaging (MRI), and ultrasound or X-rays of organs other than the breasts. To find out more about any of these techniques, click here.

In particular, MRI’s are not routinely used to diagnose breast cancer, but is often used as an alternative device if results from a diagnostic mammogram and/or ultrasound are unclear, or the extent of breast cancer in the breast tissue, or to assess the type of breast cancer (via Canadian Breast Cancer Foundation). Chiefly used to detect metastases and help in selecting a treatment, this technique can be an important complement to mammography as a screening tool in certain groups of women, particularly those with a BRCA gene mutation.

To learn more about mammograms, ultrasounds and other imaging techniques, click here.


The experience of a having a biopsy will differ, depending on what type is required. The three main types are fine needle aspiration biopsy, core biopsy and surgical biopsy. Each type of biopsy has its benefits and flaws – it’s important to discuss with your doctor which form of biopsy is the most suitable for your case. Factors you and your doctor might consider to determine which type of biopsy will be performed include how suspicious the tumour looks, how big it is, where it is in the breast, how many tumours there are, other medical problems you might have, and your personal preferences (via Rethink Breast Cancer).

Types of breast biopsy procedures include but are not limited to:

Fine needle aspiration biopsy (FNAB). A very thin needle is placed into the lump or suspicious area to remove a small sample of fluid and/or tissue. No incision, or cut, is necessary. A fine needle aspiration biopsy may be done to help see if the suspicious area is a cyst (a fluid-filled sac) or a lump.

Core biopsy. A large needle is guided into a lump or suspicious area to remove a small cylinder of tissue (also called a core). No incision is necessary.

Surgical biopsy. A surgeon removes part or all of a lump or suspicious area through an incision into the breast. There are two types of surgical biopsies. During an incisional biopsy, a small part of the lump is removed. During an excisional biopsy, the entire lump is removed.
In some cases, if the breast lump is very small and deep and is difficult to locate, the wire localization technique may be used during surgery. With this technique, a special wire is placed into the lump under X-ray guidance. The surgeon then follows this wire to help locate the breast lump.

Pathology Report, Staging and Grading

During a biopsy, tissues or cells are removed from the body so they can be tested in a laboratory. Once the health care provider receives the results, a preliminary pathology report is compiled. This information will confirm whether or not cancer cells are present in the sample and will determine which treatment method is best suited for the patient and their unique needs (via Willow Breast and Hereditary Cancer Support).

What is a pathology report and why is it important (via Willow Breast and Hereditary Cancer Support)?

Pathology reports provide important information about your breast cancer. When breast tissue is removed, a pathologist, a doctor who specializes in examining tissue and diagnosing disease, examines it under a microscope. A preliminary pathology report is prepared after a breast biopsy. A more detailed report is prepared after your breast surgery (lumpectomy or mastectomy). Only after gathering all of the details in your pathology report can your surgeon determine the next steps in your treatment.

What kind of information is contained in a pathology report (via Willow Breast and Hereditary Cancer Support)?

The report describes the characteristics of your tumour, such as:

Size of tumour The size of the cancer is one of the factors that determines the stage of the breast cancer. Size doesn’t tell the whole story – all of the cancer’s characteristics are important. A small cancer can be very fast-growing while a larger cancer may be slow-growing, or it could be the other way around. Doctors measure cancer in centimetres.

Lymph node status The lymphatic system is a series of vessels throughout the body that drain fluid from tissues. Bacteria and other microbes including cancer cells are picked up in the lymphatic fluid and trapped inside lymph nodes, where they can be attacked and destroyed by white blood cells. The lymph nodes act as filters along the lymph fluid channel. The fluid leaves the breast and eventually goes back in the bloodstream. The lymph nodes try to catch and trap cancer cells before they reach other parts of the body. Having cancer cells in the lymph nodes under your arm is associated with an increased risk of the cancer spreading, which leads to metastatic breast cancer.

Stage of the cancer Staging consists of clinical examinations and tests done to determine the extent, or stage, of the cancer. Staging considers the size of the cancer and whether it has spread to nearby breast tissue or other parts of the body. Staging is important because it will help determine the best treatment plan. The pathology report that is prepared after your surgery will provide information necessary to determine the stage of your breast cancer. Sometimes additional tests may be required.

Grade of the cancer Breast cancer is also classified as a grade. Grade indicates how aggressive the cancer is likely to be, meaning how fast it will grow and spread. The grade is determined by examining the appearance and behaviour of cancer cells under a microscope. The more cancer cells look and behave like normal cells, the slower the cancer is likely to grow and spread, and the lower the grade assigned (via Canadian Breast Cancer Foundation).

Differentiation refers to how cancer cells look and function compared to normal cells. A tumour’s level of differentiation can vary with time and can be described in degrees (via Canadian Cancer Society).

Well-differentiated cancer cells look and behave like the normal cells in the tissue they started to grow in. Tumours that contain well-differentiated cancer cells tend to be slow growing and less aggressive.

Undifferentiated or poorly differentiated cancer cells look and behave quite differently from normal cells in the tissue they started to grow in. They look immature or undeveloped and often do not resemble the tissue of origin at all. Tumours that contain undifferentiated or poorly differentiated cancer cells are more aggressive. They tend to grow quicker, spread more often and have a worse prognosis than tumours with well-differentiated cancer cells.

Moderately differentiated cancer cells look and behave somewhere between well-differentiated and undifferentiated cancer cells. Most types of cancer have moderately differentiated cancer cells.

Source: Canadian Cancer Society

Invasive or non-invasive (via Rethink Breast Cancer) Breast cancer usually begins either in the cells of the lobules, which are milk-producing glands, or the ducts, the passages that drain milk from the lobules to the nipple. The pathology report will tell you whether or not the cancer has spread outside the milk ducts or lobules of the breast where it started (breastcancer.org).

Non-invasive breast cancer (or “in situ” cancer) refers to a type of cancer where the breast cancer cells have not spread beyond their originated location – the cancer cells have not “invaded” the surrounding breast tissue. Often in situ breast cancer is referred to as a pre-cancerous condition, as it can develop into invasive cancers.

Invasive breast cancer (sometimes called infiltrating breast cancer) refers to a type of cancer where the breast cancer cells have spread beyond their originated location – the cancer cells have “invaded” the surrounding breast tissue and can travel to other parts of the body, such as the lymph nodes.

Hormone receptor status Some breast cancer cells have receptors into which the female hormone molecules (estrogen and progesterone) fit like a lock and key. These are known as hormone receptor positive (HR+) cancers. If these receptors are present, hormones will encourage the cancer to grow. It also means they are more likely to respond to hormone therapy for treatment. HR+ cancers can be estrogen receptor positive (ER+), progesterone receptor positive (PR+), or both (via Canadian Breast Cancer Foundation).

You will see the results of your hormone receptor in one of three ways:

1. The number of cells that have receptors out of 100 cells tested. You will see a number between 0 per cent (none have receptors) and 100 per cent (all have receptors).

2. A number between 0 and 3. 0 (no receptors) 1+ (a small number of cells have receptors) 2+ (a medium number of cells have receptors) 3+ (a large number of cells have receptors)

3. The word “positive” or “negative.”

Source: breastcancer.org

HER2 status Your pathology report usually includes the cancer’s HER2 Status. HER2-positive breast cancer is a breast cancer that tests positive for the protein called human epidermal growth factor receptor 2 (HER2). These proteins are receptors on breast cells, which promotes the growth of cancer cells. HER2-positive breast cancers often contain lower levels of estrogen and progesterone receptors than HER2-negative tumours. Therefore, women with HER2-positive breast cancer may benefit less from certain types of hormonal therapy.

Margin status When surgery is done to remove the whole cancer, the surgeon tries to take out all of the cancer with an extra area, or margin of normal tissue surrounding the tumour. The pathologist measures the distance between the cancer cells and the margin. Margins around a cancer are described in three ways:

  • Negative: No cancer cells can be seen at the outer edge. Usually, no more surgery is needed.
  • Positive: Cancer cells come right out to the edge of the tissue. More surgery is usually needed to remove any remaining cancer cells.
  • Close: Cancer cells are close to the edge of the tissue, but not right at the edge. More surgery may be needed.

You may see these descriptions of the type of cancer cells in your report (click on each for more information – via Canadian Breast Cancer Foundation)

Ductal Carcinoma In-Situ (DCIS)

Lobular Carcinoma in Situ (LCIS)

Infiltrating Ductal Carcinoma (IDC)

Medullary Carcinoma

Infiltrating Lobular Carcinoma (ILC)

Tubular Carcinoma

Mucinous Carcinoma (Colloid)

Paget’s Disease

Inflammatory Breast Cancer (IBC)