Receiving your pathology report is a critical step in your breast cancer treatment journey. Soon after your breast biopsy is done, you’ll be given a document detailing what kind of breast cancer you have, including genetic testing results and stage and grade. It’s essential that you understand your pathology report so that you can be an active participant in your treatment plan.

What Is Included in a Pathology Report?

Although different providers send out slightly different reports, your pathology report should include information about your:

• Tumor grade
• Lymph node status
• Margin status
• Cancer stage
• Receptor status

Below, we will help you understand some key sections and categories of your report and how their content may affect your treatment experience.

Major Sections

Nearly all pathology reports include these four sections:

• Gross description — The pathologist’s observations of the tissue with the naked eye
• Microscopic description (synoptic summary) — Observations of tissue under a microscope
• Clinical description — Details regarding how invasive the cancer is, size of the cancer, number of lymph nodes involved, where the cancer was found, whether the surgeon removed all the cancer, growth pattern, stage and grade, and predictive test results
• Final diagnosis and impression — Summary of everything the doctor has found

Key Categories

Many properties of cancer vary from person to person. These terms help define what makes your cancer unique.

Anatomic Site

The term referring to anatomic site describes the location of the tumor in your breast and whether it has spread to lymph nodes.

• Intraductal carcinoma or ductal carcinoma in situ (DCIS) — These terms describe a tumor that is growing in your milk ducts but that is noninvasive, meaning it hasn’t spread to surrounding tissue.
• Invasive cancer or invasive ductal carcinoma — This describes breast cancer that has spread to surrounding areas, including regional lymph nodes.

Size

Using images from an ultrasound or sonogram, as well as a physical exam, doctors can estimate the size of your tumor. Though imaging techniques are generally quite accurate, there’s no way to get a full picture until the tumor is removed during surgery. A pathologist can then study exactly how much of the sample contains breast cancer cells and measure the size of the tumor.

Generally, the smaller the tumor, the less intensive your treatment and the better your prognosis (outlook). However, this is not always the case — size is just one part of the broader picture of your pathology report.

Lymphovascular Invasion

Lymphovascular invasion describes whether a pathologist has identified cancer cells in the blood or lymphatic vessels of the breast. The lymphatic system is a series of channels that carry lymph fluid around the body, circulating fluid, cell waste products, and immune cells. The vascular system refers to blood vessels that carry blood from the heart to the various parts of the body and back. Lymphovascular invasion could increase the chance of your cancer spreading.

If lymphovascular invasion is not listed in your report, it typically means your pathologist did not see cancer cells in your lymph or blood.

Lymph Node Status

Lymph node status describes whether a pathologist identified cancer cells in your lymph nodes.

To determine this, your surgeon may need to remove the axillary (underarm) lymph nodes on the side where your tumor was found. They likely will combine this surgery with your tumor removal surgery. Invasive breast cancer usually spreads first to these lymph nodes, so sending them to the pathologist can help doctors predict if the cancer will spread to other organs.

Margins

Surgical margins describe how successfully the surgeon was able to remove your tumor after a breast cancer surgery (lumpectomy or mastectomy). The margin is the edge of the tissue that was removed. In an ideal surgery, margins would be negative, or clear (healthy), meaning no cancer tissue remained. This reduces the risk of leaving behind cancer cells that could regrow or spread later.

However, achieving clear margins during a lumpectomy can be difficult in some cases due to the tumor’s location or its proximity to critical structures. As a result, about 25 percent of individuals require an additional lumpectomy because their first surgery did not have negative margins, according to a study published in JAMA Surgery.

Chemotherapy and radiation can shrink tumors and provide a greater chance of clear margins when provided alongside surgery.

Grade

The pathologist determines your tumor’s histologic grade, or differentiation. This describes how different the tumor is from surrounding healthy breast cells, as well as the speed at which the cancer cells are dividing.

Your final tumor grade will be described using the Nottingham score. This score combines the differentiation with other characteristics of your cancer, such as:

• Gland or tubular formation — The formation of tiny proteins called tubules in cancer cells, which are also seen in healthy breast cells
• Nuclear grade — A comparison of the nucleus (center of the cell that contains DNA) of the cancer cells with the nucleus of healthy cells
• Mitotic rate — The speed at which tumor cells are multiplying

The Nottingham scale ranges from 1 (low-grade cancer) to 3 (high-grade cancer). Well-differentiated breast cancer cells are similar to normal breast cells, grow slowly, and are easier to treat. Moderately differentiated breast cancer cells are somewhat similar to normal breast cells. Poorly differentiated breast cancer cells are very different from normal cells, fast growing, and more difficult to treat.

MIB-1 or Ki-67 Proliferation Index

Similar to mitotic rate, this number describes what proportion of your tumor cells are dividing. Dividing cells produce Ki-67 protein, so pathologists can identify the quantity of this protein to get a sense of the rate of cell division. Typically, the lower your Ki-67 proliferation index, the less aggressive your cancer.

Hormone Receptor Status

This test determines whether the cancer cells have receptors for the hormones estrogen and progesterone. If you do have these receptors (“ER-positive” or “PR-positive” for estrogen or progesterone receptors, respectively), it means that estrogen and progesterone hormones can be identified by the cancer cells, attached to them and help them grow. This also means that hormonal therapy can be used to block the effects of these hormones to help slow or stop tumor growth.

Another receptor you may find noted on your report is called HER2. Your HER2 status plays an important role in your treatment: HER2-positive cancer cells can be treated with special therapies that target the HER2 receptor.

Stage

Finally, you will receive a cancer stage. This is based on many of the above factors, including size, spread, and lymphatic/lymph node involvement. Standard staging uses the letters T, N, and M.

The T category refers to the characteristics of the primary tumor that was identified. It includes T0, Tis, T1, T2, T3, and T4. This encompasses the size and spread of the tumor within the breast tissue. The higher the T number, the larger and more spread out the tumor. To receive a T number, you need a full biopsy that removes the tumor. This information cannot be revealed by mammogram, ultrasound, needle biopsy, or physical exam.

The N number — N0, N1, N2, or N3 — refers to whether cancer cells were identified in the lymph nodes near the affected breast and how many lymph nodes were affected. Higher N numbers mean more cancer has been found in more lymph nodes. If lymph node removal has not been conducted, your doctor cannot provide an N stage. In that case, your staging will read NX.

The M stage refers to the spread of cancer throughout your body and can be either M0 or M1. This category is based on a combination of imaging and lab results, not breast cancer surgery. Therefore, in your pathology report, M may be indicated as MX.

After all necessary tests and surgeries have been conducted, doctors will combine TNM scores to create one final stage. Invasive cancer ranges from stage 1 to stage 4. Noninvasive breast cancer is identified as stage 0. People at the same stage of breast cancer may have very different cancer profiles. That’s why it is always important to consider your health holistically and understand your specific circumstances to be an active agent in your treatment plan.

What Comes Next?

After your pathology report becomes available, your oncologist will recommend a breast cancer treatment plan. Depending on your stage, grade, and type of breast cancer, treatment might include surgery, chemotherapy, hormone therapy, targeted therapy, or a combination of these.

Before you decide on next steps, make sure you completely understand your pathology report by asking your doctor about any terms that seem unfamiliar. You have the right to fully understand your health condition before making any major decisions.

You have power in your treatment journey. All decisions about your medical care should be shared by you, your family (if appropriate), and your health care team. Remember that your doctor is your partner every step of the way.

Find Your Support

MyBCTeam is the social network for people with breast cancer. On MyBCTeam, more than 73,000 members come together to ask questions, give advice, and share their stories with others who understand life with breast cancer.

How was your experience receiving your pathology report? Do you have any tips for people going through this process? Share your experiences and thoughts in the comments below or by posting on your Activities page.