When getting your complete diagnosis, or in some cases a full pathology report (translation: detailed breakdown of your tumor), you will hear terms such as “grade” and “stage” of your cancer. Grading and staging are distinctly different things, and important because they help inform the type of treatment recommended. Here, we’ll define them for you as simply as possible.
Grade of Cancer Defined
A cancer’s grade is assigned by looking at the cancer cells under a microscope, using tissue from a biopsy or after breast cancer surgery. This grade is a description and indicator of how quickly and aggressively a tumor is likely to spread and grow.
While you all get A+’s in our book, the pathology report grades run on a scale from 1 to 3. A lower grade signifies that the cancer is slower-growing and less likely to spread, while a higher number means faster-growing cancer that’s more likely to spread.
- Grade 1 or low grade (sometimes called well differentiated): The cells are slower-growing, and look more like normal breast tissue.
- Grade 2 or intermediate/moderate grade (moderately differentiated): The cells do not look like normal cells, and are growing and dividing a little bit faster than they normally would.
- Grade 3 or high grade (poorly differentiated): The cancer cells look very different from normal cells, with many dividing quickly to make new cancer cells.
Considerations for Grading a Tumor
There are three factors pathologists look at when grading a tumor:
- Tubule formation evaluates how much of the tumor tissue has normal breast (milk) duct structures
- Nuclear grade studies the size and shape of the nucleus in tumor cells
- Mitotic rate analyzes the amount of dividing cells present, measuring how fast the tumor cells are growing and dividing
Stage of Cancer Defined
Stage, as it pertains to breast cancer, is determined by tumor size, lymph node involvement, and whether it has spread to another part of the body and/or the number of tumors present. There are five stages, represented by fancy Roman numerals. They get more complicated after stage 0, with letters added to describe other variables.
We try to keep things straightforward and un-dense here, which is sometimes difficult with all the medical and scientific info. So, rather than reading all of the staging definitions below, we suggest moseying on down to find your descriptor.
Before we begin, a quick encyclopedia moment:
- Tumors are measured in millimeters and centimeters (10 mm equals 1 cm)
- Axillary lymph nodes = lymph nodes in the armpit region/underarm area; this would be the first place breast cancer tends to travel to first if it’s going to spread
- The initial staging might change once biopsy and diagnostic imaging (such as MRI) results are received
Other terms that may be used to describe the stage of the breast cancer:
- Local: The cancer is confined within the breast
- Regional: The lymph nodes, mainly in the axilla, are involved
- Distant: The cancer has spread to other parts of the body
Stage 0 describes all non-invasive cancers, such as DCIS and LCIS, or even pre-cancers. At this stage, there is no evidence that the cancer cells are invading surrounding tissue.
Stage I is an early invasive cancer, where the cancer cells have spread to surrounding breast tissue but are still contained in a small area.
- IA: No lymph node involvement, with a small tumor measuring up to 2 cm or less (the size of a grape)
- IB: Small amount of cells in the lymph nodes with a tumor measuring up to no larger than 2 cm OR small groups of cancer cells (larger than 0.2 mm but smaller than 2 mm) are in the lymph nodes, with no tumor in the breast
Stage II indicates the cancer is still contained in a region of the breast, but the tumor has grown larger, to 2-5 cm.
- IIA: No lymph node involvement, but tumor measuring 2-5 cm OR there is cancer in 1-3 lymph nodes under the arm or in the breast bone larger than 2 mm, with either a small tumor in the breast of up to 20 mm, or no tumor at all.
- IIB: A tumor of 2-5 cm is present, and: small groups of breast cancer cells (0.2mm - 2 mm) are found in lymph nodes or have spread to 1-3 nodes either under the arm or near the breastbone OR the cancer has not spread to any lymph nodes, but the breast tumor measures more than 5 cm.
Stage III describes the further spreading of cancer into the breast tissue and/or chest wall, and/or with a tumor over 5 cm.
To confuse things more, there is a 3rd subcategory for this stage.
- IIIA: No tumor is found in the breast, or the tumor may be any size, with cancer in 4 to 9 axillary lymph nodes or lymph nodes near the breastbone OR the tumor is larger than 5cm with cancer having spread to 1-3 nearby lymph nodes OR the tumor measures more than 5 cm, is found in 4 to 9 axillary lymph nodes,
- IIIB: Indicates a tumor of any size that has spread to: the chest wall and/or skin of the breast (causing swelling, inflammation), up to 9 axillary lymph nodes or lymph nodes near the breastbone, or that the cancer cells have broken through the skin causing an ulcerated area OR the tumor measures more than 5 cm, is found in 4 to 9 axillary lymph nodes
- IIIC: There is either no tumor at all, or one of any size in the breast, and cancer has spread to one of the following: the chest wall and/or the skin of the breast, 10 or more axillary lymph nodes, lymph nodes above or below the collarbone, or to lymph nodes near the breastbone
Stage IV indicates that cancer has spread beyond the breast and axillary lymph nodes, to other lymph nodes or organs of the body. Also called metastatic breast cancer, stage IV can either be a recurrence of a previous breast cancer that has spread or given as an initial diagnosis. When given as an initial diagnosis, it is known as“de novo,” if it has already spread outside the breast to other parts of the body.
There are so few things we can control while going through breast cancer; however, I always felt that having as much information as possible gave me a bit of control over the decisions I had to make, and allowed me to understand and accept why my doctor was recommending certain treatment (for example, with mine at grade 3, I understood why she had to be so aggressive).
When you know these details and descriptions, it better equips you to have conversations with your doctor, or to ask questions if something is confusing or doesn’t seem right.
Regardless of what stage your cancer is, we at Stage are here solely to share our experiences and support you through this stage of your life (see what we did there?)—but never to take the place of medical professionals or advice.