Understanding Your Pathology Report
Non-Invasive vs. Invasive Carcinoma
Non-invasive carcinomas stay within the milk ducts or lobules and do not
have the potential to spread. They are sometimes called “carcinoma
in situ”. Invasive carcinomas grow into the surrounding normal healthy
breast tissue and have the potential to spread to nearly lymph nodes or
beyond the breast to other organs.
The size of the tumor indicates how wide the tumor is at its largest point.
It is generally reported in centimeters (cm). Size is important in determining
the stage of the cancer, and also surgical treatment options.
This is the area of normal tissue that surrounds abnormal cancer cells.
The margin should be free of any abnormal cancer cells when the cancer
is removed. If cancer cells are present at the margins, then more tissue
must be removed to make sure there are “clear margins,” so
no abnormal cells are left behind.
Lymph Node Involvement
Evaluating lymph nodes for potential spread of cancer cells is a valuable
tool used to predict the risk of systemic involvement. If a lymph node
is free or clear of cancer, then it is considered negative. If a lymph
node has cancer cells in it, it is considered positive. Your pathology
report will indicate how many total lymph nodes were removed, and how
many contained cancer cells.
Cancer cells have spread outside the wall of the lymph node into surrounding tissue.
A “score” which indicates how abnormal the breast cancer cells
look when compared to healthy breast cells. There are three grades: I
(low grade or well-differentiated), II (intermediate grade or moderately-differentiated),
and III (high grade or poorly-differentiated). Higher grade cancers look
the most abnormal and are generally more aggressive than low grade cancers.
Estrogen Receptor (ER), Progesterone Receptor (PR)
Estrogen and Progesterone Receptors are proteins found in and on breast
cells which pick up signals telling the cell to grow. Detecting these
receptors on a tumor help identify patients who are likely to benefit
from hormonal therapy.
HER2/Neu IHC or ISH
The HER2 gene makes HER2 proteins, which are receptors on breast cells
which normally control how a breast cell grows and repairs itself. About
20% of breast cancer cells have too many copies of the HER2 gene, resulting
in too many HER2 receptors, which results in a breast cancer cell which
grows in an uncontrolled way.
A breast cancer cell which has HER2 overexpression or amplification is
considered HER2 positive. There are medications which specifically target
HER2 positive breast cancer cells.
Proliferation markers which measure the rate that breast cancer cells are
growing. The test can determine what percentage of the cancer cells are
preparing to divide. Higher markers indicate a faster rate of growth.
Lymphovascular Invasion (LVI)
Presence of tumor cells within blood vessels or lymphatic channels. This
increases the risk of cancer cells spreading or coming back in the future.
It is typically reported as present or absent.
Determined based on the whether the cancer is non-invasive or invasive.
If it is invasive cancer, then the tumor size, presence or absence of
lymph node involvement, and whether the cancer has spread beyond the breast
to other organs determines the stage.
Learn more about other cancer terms.