Following is a brief outline of the common breast cancer tests that may be conducted at diagnosis. Remember this information is introductory and you are urged to seek more detailed information from your doctor or specialist
Blood Test
If cancer is present in the body, it will normally produce a certain protein in the blood. This can serve as what doctors call a “marker”. There are blood tests which determine the presence of these “cancer markers” or “tumour markers”. However, a marker test that registers normal does not prove that you are cancer-free, nor does an elevated test result prove that you have progression or recurrence of cancer. It may also be the case that a blood test is not ideal for a particular type or stage of cancer.
Biopsy
Biopsy is the general term for a small operation which removes tissue to enable the microscopic analysis of cells. It is far more accurate than an ultrasound or mammogram in helping doctors pinpoint the size and type of breast cancer. There are two main types of biopsies used when diagnosing breast cancer: needle biopsies and surgical biopsies.
Needle Biopsies
There are two types; Fine-needle aspiration (FNA) and Core-needle biopsy. Both can be done in your Doctor’s office.
Fine-needle aspiration (FNA)
A thin needle is used to extract cells from the suspected area. This procedure only takes a few minutes and can be done in your Doctor’s office usually without the need of anaesthetic. FNA is the least invasive biopsy technique. However, it also has the highest rate for “false negative” results. This is when the result is called normal despite cancer cells actually being present. This can happen when the needle fails to pick up the cancerous cells.
Core-needle biopsy
The most commonly used biopsy procedure, this technique uses a small cut in the skin to remove tissue samples from the centre of the lump. As this procedure provides larger tissue samples, they are less likely to be damaged and usually provide a more accurate diagnosis. This process sometimes involves a vacuum pump if larger samples are needed.
Surgical Biopsy
There are two types; incisional and excisional. Both can be done in an outpatient clinic or hospital with local anaesthetic.
Incisional biopsy
This involves the removal of a small piece of tissue for examination. It is usually done when needle biopsies are inconclusive or if the suspected breast lump is too large to be easily removed.
Excisional biopsy
The most involved type of biopsy. It attempts to remove the entire lump of tissue from the breast and is the most conclusive way to make a diagnosis and reduce the chance of a false negative result.
Node Testing
If cancer has entered the lymph nodes there is more danger of it spreading throughout the body. Therefore, checking the status of lymph nodes is important. It is usually done in two ways; axillary lymph node dissection and sentinel lymph node dissection
Axillary lymph node dissection
This is where around 10 of the nodes found in the armpit are surgically removed for checking. The pathologist then counts how many are cancerous.
Sentinel lymph node dissection
This is less invasive because only up to 3 nodes that directly drain lymph fluid from the area around the tumour are removed. The nodes to be removed are identified by injecting a blue dye in the breast near the tumour. The first nodes to receive this dye are the sentinel nodes. If these nodes are not found to be cancerous, then it cannot have spread to the rest.
IHC and ISH Tests
There are two ways of testing HER2 receptor levels; IHC (immunohistochemistry) and ISH (in situ hybridization).
IHC or immunohistochemistry
A test done on the breast tissue removed by surgery which measures the protein made by the HER2 gene. The results are given as either 0, 1+, 2+, or 3+.
ISH or in situ hybridization
Measures the amount of HER2 gene in the cells and is considered more accurate that the IHC test. The more copies of the HER2 gene, the more HER2 receptors the cells have. With the ISH test you get a score of either “positive” or “negative”. There are two types of ISH tests: FISH , fluorescence in situ hybridization, and CISH, chromogenic in situ hybridization.
Pathology report
A pathology report is compiled with the test results of the all the studies done on the tissue removed from the body. The breast cancer stage may also be included in the report. TNM staging describes a tumour in regard to its size and spread using three key measures.
TNM refers to:
T - the size of the tumour.
N - the extent to which lymph nodes are involved.
M - the presence or absence of distant metastasis.
The information in the report will help you and your doctor decide on the best treatment for you
