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Diagnosing breast cancer
Diagnosis is the process of finding the cause of a health problem. The process of diagnosis may seem long and frustrating, but it is important for the doctor to rule out other reasons for a health problem before making a cancer diagnosis. Diagnostic tests for breast cancer are usually done when:
- the symptoms of breast cancer are present
- the doctor suspects breast cancer after talking with a person about their health and completing a physical examination
- a screening mammography suggests a problem with the breast
Many of the same tests used to initially diagnose cancer are used to determine 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. Tests may include the following.
The medical history is a record of present symptoms, risk factors and all the medical events and problems a person has had in the past. The medical history of a person's family may also help the doctor to diagnose breast cancer.
In taking a medical history, the doctor will ask questions about:
- a personal history of
- breast disease or breast cancer
- hormone replacement therapy
- previous radiation therapy to the chest
- a family history of
- breast cancer
- other cancers, such as ovarian and colon cancer
- signs and symptoms that may suggest breast cancer
A physical examination allows the doctor to look for any signs of breast cancer. During a physical examination, the doctor may:
- do a clinical breast examination (CBE) to check the breasts and lymph nodes for:
- breast lumps
- hardening or thickening in the breast tissue
- skin changes on the breast, including dimpling
- changes in the nipples
- swollen lymph nodes in the armpit (axilla) and above and below the collarbone
- feel the abdomen to check for an enlarged liver
- listen to the lungs
Diagnostic mammography is an x-ray that uses small doses of radiation to make an image of the breast on film. It is used to:
- follow up on abnormal results of a screening mammography or a clinical breast examination
- diagnose breast cancer
- help find an abnormal area to be sampled during a biopsy
Ultrasound uses high-frequency sound waves to make images of structures in the body. Breast ultrasound is not as sensitive as mammography in diagnosing breast cancer. It may be used to:
- examine a breast lump or abnormality found during a clinical breast examination or mammogram
- determine if a breast lump is a solid tumour or a fluid-filled cystcystA sac in the body that is usually filled with fluid or semi-solid material.
- find an abnormal area for a biopsy
During a biopsy, tissues or cells are removed from the body so they can be tested in a laboratory. The pathology report from the laboratory will confirm whether or not cancer cells are present in the sample.
A breast biopsy is the only definite way to diagnose breast cancer. Most biopsy samples taken from breast lumps are found to be benign (non-cancerous).
The type of biopsy will depend on whether the lump can be felt (palpable) or not (non-palpable). Ultrasound or computed tomography (CT) scan may be used to guide the biopsy. The types of biopsy that may be used are:
- fine needle aspiration (FNA)
- core needle biopsy
- stereotactic core needle biopsy
- wire localization biopsy
- surgical biopsy to remove part of or all of a breast lump or abnormal area
Scintimammography uses a radioactive material (known as a radioactive isotope) and a special camera to take pictures of the breast. It is done:
- to check breast lumps that do not show up clearly on a mammogram because of:
- scar tissue from previous surgery or radiation therapy
- dense breast tissue
- breast implants
- when multiple tumours are seen in the breast
- to scan the lymph nodes in the armpit (axilla) to see if they contain cancer
Scintimammography is not commonly used. It does not replace mammography, which is still the standard imaging test used to diagnose breast cancer. At present, scintimammography is considered a second-line diagnostic tool. It may be used in some women to assess breast abnormalities after a mammogram.
Ductography is an x-ray procedure that is sometimes used to help determine the cause of nipple discharge. It is used to:
- look at the breast ducts
- help diagnose intraductal papillomas (a common non-cancerous cause of nipple discharge) and other breast conditions
Ductography may be used with diagnostic mammography. It is not used instead of mammography to diagnose breast cancer.
A lymph nodelymph nodeA small, bean-shaped mass of lymphatic tissue along lymph vessels (tubes through which lymph fluid travels in the body). Lymph nodes store lymphocytes (a type of white blood cell that fights germs, foreign substances or cancer cells) and filters bacteria and foreign substances (including cancer cell biopsy removes lymph nodes during a surgical procedure so they can be examined under a microscope to find out if they contain cancer.
With breast cancer, lymph nodes from under the arm (axilla) are removed. Breast cancer cells can travel through the lymph system, and the first place they may spread is to these lymph nodes. The number of lymph nodes that have cancer helps to determine the stagestageA description of the extent of cancer in the body, including the size of the tumour, whether there are cancer cells in the lymph nodes and whether the disease has spread from its original site to other parts of the body. of breast cancer.
Axillary lymph node dissection
Axillary lymph node dissection (ALND) is a surgical procedure to remove the lymph nodes under the arm.
- Most breast cancers require staging with ALND.
- ALND is the standard method of checking lymph nodes in most centres in Canada.
Sentinel lymph node biopsy
The sentinel node is the first lymph node in a chain or cluster of lymph nodes that receives lymph fluid from the area around a tumour. Cancer cells will most likely spread to these lymph nodes. Sentinel lymph node biopsy (SLNB) is the removal of the sentinel node so it can be examined to see if contains cancer cells.
SNLB may be offered to women with breast tumours smaller than 5 cm, and the axillary lymph nodes cannot be felt during an examination by the doctor.
SLNB may not be suitable for women:
- who had breast surgery or radiation therapy in the past
- with axillary lymph nodes the doctor can feel
- with locally advanced or advanced breast cancer (tumours greater than 5 cm in size)
- with tumours in more than one area in the breast (multifocal tumours)
- with metastatic breast cancer
- inflammatory breast cancer
- who have had breast reduction surgery, or have breast implants
Blood chemistry tests measure certain chemicals in the blood. They show how well certain organs are functioning and can also be used to detect abnormalities. They are used to stage breast cancer.
- Urea (blood urea nitrogen or BUN) and creatinine may be measured to check kidney function. Kidney function is checked before chemotherapy is given and may be rechecked during or after treatment.
- Alanine aminotransferase (ALT), aspartate transaminase (AST) and alkaline phosphatase may be measured to check liver function.
- Increased levels could indicate that cancer has spread to the liver.
- Alkaline phosphatase can also be used to check for cancer in the bone.
- Increased levels could indicate that cancer has spread to the bone.
A bone scan uses bone-seeking radioactive materials (radiopharmaceuticals) and a computer to create a picture of the bones. It is used to see if breast cancer has spread (metastasized) to the bones.
A bone scan may be done if:
- alkaline phosphatase in the blood is increased
- there are lymph nodes in the armpit (axillary lymph nodes) that can be felt
- the primary breast tumour is larger than 5 cm
- the woman has aches and pains that may be caused by bone metastases
A bone scan is not done in women who have stage I breast cancer.
If the blood chemistry tests show increased levels of liver enzymes, a liver ultrasound may be done to check if the cancer has spread to the liver (liver metastases).
An x-ray uses small doses of radiation to make an image of the body's structures on film. A chest x-ray may be done to find out if breast cancer has spread to the lungs.
MRI uses powerful magnetic forces and radio-frequency waves to make cross-sectional images of organs, tissues, bones and blood vessels. A computer turns the images into 3-dimensional pictures. An MRI of the breast is not routinely used to diagnose breast cancer, but may be done in certain situations to:
- find the primary tumour in the breast
- MRI may be used if cancer is found in the axillary lymph nodes or if a woman has Paget disease of the nipple.
- find out the extent of cancer in the breast tissue (local disease)
- MRI may be used when test results from physical examination, mammography or ultrasound are not clear.
- better examine an abnormality found on mammography
- MRI may be used if the abnormality cannot be found with other tests, such as a clinical breast exam or breast ultrasound.
- It may also be used if the abnormality can be seen from only one view of the results of a mammography.
- check the condition of breast implants, especially if the doctor suspects that an implant has ruptured
A complete blood count (CBC) measures the number and quality of white blood cells, red blood cells and platelets. A CBC is done to provide a baseline for future blood counts taken during and after treatment.
Hormone receptor testing determines the amount of estrogen receptor (ER) and progesterone receptor (PR) in the breast cancer cells. This information will help doctors determine the woman's treatment plan.
ERBB2 is a gene that has changed (mutated) so it helps a tumour grow (oncogeneoncogeneA gene involved in the control of cell growth and division that may cause the growth of cancer cells.). It is more commonly known as HER2 (or HER2/neu). HER2 stands for human epidermal growth factor receptor 2.
HER2 status testing is done to find out the amount of HER2 produced by a breast tumour. This information will help doctors to determine the woman's treatment plan.