Your breast cancer pathology report is one of the most important documents you’ll get during the diagnostic process. It can be packed with information and may include many strange-sounding terms. If you were recently diagnosed with hormone receptor-positive (HR-positive), HER2-negative (HER2-) breast cancer, understanding how to read your pathology report will give you a better idea of your diagnosis and treatment choices.
What Is a Breast Cancer Pathology Report?
A breast cancer pathology report includes documents that outline the results of your breast cancer tests. Specialized doctors called pathologists study samples taken from your breast tissue and cells. Your report breaks down what they found.
Despite what the name may suggest, your pathology report isn’t one standard report that summarizes the results of a single test. Depending on the tests your doctor orders, you may get different reports from different labs. Together, this collection of test results is your pathology report.
Breast cancer pathology reports usually use a lot of medical terms because they’re written for health care professionals. But you can learn what they mean and break down some of the main sections of the report to better understand what it says.
But not all breast cancer pathology reports look the same. You may or may not see certain terms or sections because:
- Different labs use different words for the same information
- Needle biopsies give less information than surgical biopsies
- You’ll only do certain tests if you have a specific cancer or diagnosis
- You've had cancer treatment before surgery, instead of surgery as your first treatment
Types of Breast Cancer Pathology Reports
There are two main types: a biopsy pathology report and an excision pathology report with a synoptic summary.
What is a biopsy pathology report?
This breaks down the findings from a small tissue sample taken during a biopsy. If the pathologist finds cancer, then you’ll likely have surgery to remove it (also known as an excision).
“The core biopsy is just the beginning,” says Generosa Grana, MD, director of the MD Anderson Cancer Center at Cooper in Camden, New Jersey. “You can’t make any definitive decisions — regarding hormone therapy, chemotherapy, HER2-targeted therapy — until you see the final pathology.”
Your doctor will use the results in the biopsy pathology report along with the visible signs and symptoms to make decisions. The biopsy and your symptoms will help your doctor know if you have cancer. If you do have cancer, the biopsy pathology report guides the first set of cancer management decisions, such as which kind of treatment you should have first.
What is an excision pathology report?
This final pathology report will look very similar to the biopsy pathology report. But unlike the biopsy pathology report, the excision pathology report will have information that will help figure out what stage of cancer you may have. The synoptic summary in this pathology report describes the entire cancer as a whole. Compared to a biopsy pathology report, an excision pathology report is more like a complete snapshot.
“That final pathology is then used to make decisions on treatment,” Grana says.
What’s the Purpose of a Breast Cancer Pathology Report?
Breast cancer pathology reports describe the main features of your breast cancer and your breast cancer diagnosis. This information helps your doctor decide the best treatment path for you.
To decide how best to manage your cancer, your doctor will look at your health, age, genetics, and the way the cancer looks in person and on imaging tests, among other things, Grana says. In other words, the breast cancer pathology report is important, but it’s just one piece of the puzzle.
Decoding Your Breast Cancer Pathology Report
These are some of the most common terms you could see in your report and what they mean for you.
Diagnosis
The diagnosis section, which lists the pathologist’s final diagnosis, is the most important part of your report. If they find cancer, the diagnosis section will describe the type of cancer you have and its most important features. It may also include information such as:
- Cancer type
- Tumor size
- Tumor grade
- Hormone receptor status
- HER2 status
- Lymph node status
- Where on the body the cancer is located (anatomic location)
Synoptic summary
If you had surgery to remove (excise) the breast cancer, you’ll see a synoptic summary. This section summarizes the test findings about the sample and the cancer. It’ll describe what the tissue cells look like under a microscope. It may also break down how the cancer cells compare to the normal cells. This won’t be on your pathology report if you had a breast biopsy only.
Tumor size
You may see a section for tumor size. This is the longest length of the tumor in the tissue sample taken out during surgery. It’s usually measured in centimeters or millimeters.
The size of your tumor is one factor used to decide the breast cancer stage. If the pathologist stages your cancer, you may see the prefix “p” added to the common TNM staging system on your pathology report. TNM stands for “tumor, nodes, and metastases.”
In this system, the letter “T” followed by a number tells you the size of the tumor:
- Tis means carcinoma in situ (abnormal cells that haven’t spread from the original location)
- T0 means a tumor wasn’t found
- TX means the tumor size couldn’t be accurately measured
- T1 is a tumor 2 centimeters or smaller
- T2 is a tumor larger than 2 centimeters but no larger than 5 centimeters
- T3 is a tumor larger than 5 centimeters
- T4 is a tumor of any size but has spread past the breast tissue to the chest wall, skin, or both
Generally, the smaller the tumor size, the better the prognosis.
Cancer type
You may see one of the following types of breast cancer or abnormal cell growth in your pathology report under the final diagnosis section:
Invasive ductal carcinoma (IDC). About 8 in 10 breast cancers are IDC. This is a type of cancer that starts in your milk ducts and moves to nearby breast tissue.
Invasive lobular carcinoma (ILC). This type of breast cancer — also called infiltrating lobular carcinoma — is the second most common type of breast cancer after IDC. You may see a subtype of ILC listed on your report, such as solid or signet ring cell. These describe the pattern in which the cancer cells grow.
Inflammatory breast cancer. This is a rare type of breast cancer caused when breast cancer cells block lymph vessels in the skin. It spreads quickly. Your doctor will usually make this diagnosis. But your excision pathology report may note that the cells look like inflammatory breast cancer. They may use “stage pT4d” in the synoptic summary.
Ductal carcinoma in situ (DCIS). DCIS is a noninvasive cancer, meaning it hasn’t spread beyond the tissue it’s in. With breast cancer, that means it hasn’t spread past your milk ducts. DCIS isn’t dangerous, but it may mean you have a higher chance of invasive breast cancer later on.
Lobular carcinoma in situ (LCIS). LCIS means you have abnormal cells that haven’t spread beyond the milk glands in your breast. It’s not cancer. But having LCIS may raise your chances of invasive breast cancer in the future.
Paget disease. This makes up only 1 in 100 breast cancers. Paget disease involves your areola and the skin of your nipple. These cancer cells are usually DCIS. They may be staged in the pathology report as “pTis,” meaning they haven’t spread beyond the original tissue.
Phyllodes tumors of the breast. This is another rare type of breast cancer that starts in the breast’s connective tissue or stroma. Only about 1 in 4 phyllodes tumors are cancerous.
Tumor grade
The tumor grade helps doctors know how likely the cancer is to grow and spread. To figure out the tumor grade, experts look at a few key features of the cancer cells, such as:
- How they’re arranged around each other
- If they form tubules, also known as gland formation
- Mitotic count, or how many of them are dividing
- Nuclear grade, or how much they look like normal breast cells
Gland formation, nuclear grade, and mitotic count are often assigned numbers. The numbers are based on how normal or abnormal the cancer cells and their growth patterns look. Then, experts add the numbers up to create a grade number. This is called the Nottingham grading system, which will most commonly show up on your pathology report as grade 1, 2, or 3.
Grade 1, well differentiated. These tumor cells look relatively normal and aren’t growing or spreading quickly. A tumor is assigned grade 1 if it scores between 3 and 5.
Grade 2, moderately differentiated. These tumor cells and growth patterns look more abnormal. Grade 2 tumors fall between grade 1 and grade 3. The numbers add up to a 6 or 7.
Grade 3, poorly differentiated. These tumor cells don’t have normal features. They also grow and spread faster. This grade means your numbers add up to an 8 or 9.
Hormone receptor (HR) status
Some cancer cells have hormone receptors, which are proteins. When hormones attach to these proteins or receptors, the cancer cells grow. All breast cancers are tested for hormone receptor (HR) status to see if they have the receptors for estrogen and progesterone. Results will appear on your pathology report as either positive or negative. This will help guide your treatment. Options include:
Hormone receptor-negative (HR-negative). HR-negative tumors have little to no hormone receptors. HR-negative means the tumor is estrogen-receptor-negative (ER-negative) or progesterone-receptor-negative (PR-negative).
Hormone receptor-positive (HR-positive). HR-positive means the cancer cells are estrogen-receptor-positive (ER-positive) and progesterone-receptor-positive (PR-positive). It has a lot of hormone receptors. In this case, your treatment may include hormone therapy to keep the cancer cells from getting the estrogen they use to grow.
Estrogen-receptor-positive (ER-positive). ER-positive means the cancer has estrogen receptors.
Progesterone-receptor-positive (PR-positive). PR-positive means the cancer has progesterone receptors.
Estrogen-receptor-negative (ER-negative). ER-negative means the cancer doesn’t have estrogen receptors.
Progesterone-receptor-negative (PR-negative). PR-negative means the cancer cells don’t have progesterone receptors.
Sometimes, breast cancers can be ER-positive and PR-negative. But they’ll be treated the same as breast cancers that are positive for both hormone receptors, as hormone therapy is designed for ER-positive cancers anyway.
HER2 status
Human epidermal growth factor receptor 2, known as HER2, is a protein on the surface of some breast cancer cells. It helps them grow and survive. All breast cancers are tested for HER2 status, which helps inform your treatment.
HER2-positive. This means your breast cancer cells have too many copies of the HER2 gene, which make above-normal amounts of the HER2 protein. You may hear your doctor call this HER2 over-expression. HER2-positive breast cancers grow and spread more quickly than other kinds.
HER2-negative. HER2-negative breast cancer cells have little to no HER2 protein.
Tumor margins
When a surgeon removes a tumor, they’ll also remove a bit of healthy tissue around it called the margin. The margin is colored with ink. Then, the pathologist will look at the tumor under a microscope to see how close the cancer cells are to those margins. This helps them know if the entire tumor was removed.
Positive margins. If your report says there are positive or “involved margins,” it means the cancer cells are right next to or in the margins. This can mean some cancer was left behind. Your doctor may suggest more surgery or treatment to remove more tissue.
Negative margins. This may also appear on your pathology report as “clean,” “clear,” or “not involved” margins. Seeing negative margins on your breast cancer pathology report means there aren’t cancer cells in or near the margins — only normal tissue. This usually means you won’t need any more surgery.
Close margins. This is when the cancer cells get close to but don’t touch the edge of the margins. Depending on how close they are to the edge, your doctor may suggest more surgery.
You won’t see this information on your report if you just had a breast biopsy. That’s because a breast biopsy is usually a tiny sample of the tumor. Margins are usually determined when the surgeon removes the entire tumor.
Lymph node status
If you had lymph nodes from your underarm area removed during surgery to see if they have cancer, this may show up on your pathology report as either positive or negative.
Lymph node-negative. This means none of those lymph nodes have cancer.
Lymph node-positive. This means at least one of the lymph nodes has cancer.
This information helps your doctor stage your breast cancer. In the TNM staging system, the letter “N” followed by a number tells you whether the cancer has spread to lymph nodes near the breast. It also tells you how many lymph nodes are affected.
While many lymph node features can change the N stage, the number of underarm lymph nodes with cancer plays a key role:
- N1 means cancer has spread to one to three underarm lymph nodes (or that cancer was found in the lymph nodes near the breast bone in internal mammary lymph nodes).
- N2 means cancer has spread to four to nine lymph nodes under the arm (or that the internal mammary lymph nodes have gotten bigger because of cancer).
- N3 means 10 or more underarm lymph nodes have cancer (or that cancer has spread to the lymph nodes under or above your collarbone).
In addition to how many lymph nodes have cancer cells in them, the pathologist may also use terms to explain how many cancer cells are in each lymph node:
- Isolated tumor cells means fewer than 200 cancer cells are in the lymph node or that the cancer is 0.2 millimeters or smaller.
- Micrometastasis means there are 200 cancer cells or more in the lymph node or that the cancer ranges from 0.2 to 2 millimeters in size.
- Macrometastasis means the cancer is bigger than 2 millimeters.
- Extracapsular extension means the cancer has spread beyond the lymph node wall.
This information can help you and your doctor decide which treatments you may need alongside surgery.
Other terms you might see
Depending on other tests and findings, you may see additional results on your breast cancer pathology report.
Proliferation rate (Ki-67, MIB1). Proliferation rate is the percentage of cancer cells that are multiplying. In general, the bigger this number, the more aggressive the cancer. Sometimes, it can be a good way to predict prognosis.
Noninvasive vs. invasive. Noninvasive usually means you have DCIS or LCIS, as the abnormal cells haven’t spread beyond their original location.
Invasive, or infiltrating, means the abnormal cells have spread from their initial location in the milk ducts or the glands and into nearby breast tissue. It may also mean that it’s spread to nearby lymph nodes and other parts of the body. The most common types of invasive breast cancer are invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC). The type of invasive breast cancer will be included in the diagnosis section of the pathology report.
“The long-term prognosis is based on the amount of invasive disease in a specimen, but management of the breast has to include both the noninvasive and the invasive,” Grana says.
Lymphovascular invasion. You might also see this listed as “vascular” or “angiolymphatic invasion.” This tells you if the cancer cells have made their way into lymph channels (lymphatic invasion) or small blood vessels (vascular invasion). These two types of invasion are usually together in the lymphovascular section.
There’s lymphatic or vascular invasion if your report says “present.” This may mean you have a more aggressive tumor that has or will spread beyond the breast or that the cancer may come back after treatment. If the report says “absent,” you don’t have either invasion.
Immunohistochemistry (IHC) test results. IHC is usually the first test done to figure out HER2 status in early breast cancer. It flags the amount of HER2 protein on the surface of the cancer cells. The results are scored numerically:
- 0 or 1+ means it’s HER2-negative.
- 2+ means the results aren’t clear and need to be affirmed by a fluorescence in situ hybridization (FISH) test.
- 3+ means it’s HER2-positive.
IHC for prognostic markers. IHC can pick up on other molecular signs that give your doctor more insight into your prognosis. It can help your doctor diagnose cancer and figure out what treatment options may be best.
FISH test results. The second major test for HER2 status testing behind IHC is the FISH test. This finds the number of copies of the HER2 gene in the cancer cells. This can help doctors find out if your breast cancer is HER2-positive. It may be a better option for people who received a “borderline” (2+) result from their IHC test because FISH tests are often used to confirm your HER2 status.
Results of a FISH test for early breast cancer will be listed in one of two ways on your pathology report. If you see the word “negative” or “non-amplified,” that means your tumor is HER2-negative. If your report says “positive” or “amplified,” the tumor is HER2-positive.
Microscopic description. This describes what the tissue sample and cancer cells look like under a microscope. It includes changes that could be cancerous or noncancerous.
Tumor necrosis. This means that there are dead cancer cells in the tissue. Tumor necrosis could mean the breast cancer is more aggressive.
What Other Information Is Included in a Breast Cancer Pathology Report?
Your pathology report will also include other information about you (the patient information) and the steps taken to get the results.
Patient information. This section will include basic information about you, such as your:
- Age
- Date of birth
- Medical record number
- Name
- Sex
This section may also include the date of any breast biopsies and the name of the doctor who ordered the report.
Doctor and lab information. You may see the pathologist’s and doctor’s contact information here instead. You may also find some information about the lab where your samples were tested.
Specimen(s) received. This could also be listed as “specimen source” or “specimen submitted” on your pathology report. It’ll have information about:
- Where in your breast the surgeon took a sample from, such as the left or right breast
- The date the tissue was removed
- The type of biopsy or surgery done
- The date that the pathologist got the tissue sample
Procedure. This section describes the type of biopsies you had:
- Needle biopsy or surgical biopsy for tumor tissue sample
- Sentinel lymph node biopsy or axillary lymph node dissection for lymph nodes
Clinical history. Your clinical history will outline your initial diagnosis before the breast biopsy. It may also include:
- A short summary of your symptoms
- How the cancer was first found
- Where your biopsy was, such as the left or right breast
This section may also show up in clinical information, clinical diagnosis, or preoperative diagnosis sections on the report.
Gross description. It’s also called the macroscopic description. This is the pathologist’s description of what the sample looks like to the naked eye before they see it under a microscope. If there are multiple samples, there will be a gross description for each one, which the pathologist will assign a reference number or letter to.
This section may include notes on the tissue, including:
- Color
- Size
- Weight
- Texture
- Whether there are any masses or lesions on the sample, where they are, and what they look like
- Other visual features of the tissue
The pathologist will also note how they handled the sample once they got it.
Comments. This can appear at the end of the final diagnosis section, at the end of the synoptic summary, or both. It may include additional test information or further explain your results.
Treatment effects. You’ll see this section if you had treatment before surgery to remove a tumor. It usually lists:
- Tumor bed size, or the size of any remaining cancer found during the surgery
- Tumor bed cellularity, or the percentage of cancer cells in the tumor bed
- No residual carcinoma if there’s no cancer found during the surgery
Key Takeaways
A breast cancer pathology report is a useful breakdown of your cancer’s key features. It helps your doctor suggest the best treatment for you. You’ll get the most complete snapshot in the diagnosis section, where you can find out whether the cells are cancerous, the cancer type, and the cancer stage.
From there, you may or may not see different terms depending on how the tissue sample was tested. What appears on your report will also change depending on whether you had a breast biopsy or a bigger surgery.
If you don’t know what a term means, don’t be afraid to ask your doctor. You can also ask a member of your care team to walk through the report with you using simple terms, focusing on the results that most affect your treatment choices and outlook. If you have concerns about the results, you can always ask for a second opinion from a consulting pathologist.
Pathology Report Term | What It Means | Why It Matters for You |
| Size | The longest length of the tumor in the tissue sample removed during surgery, scored T1-T4 (can include TX, T0, and Tis) | This is one part of breast cancer staging. Generally, the smaller the tumor size, the better your chances of survival. |
| Microscopic description | What the tissue sample and tumor cells look like under a microscope | It includes features that could be cancerous or noncancerous and helps inform your treatment plan going forward. |
| Hormone receptor (HR) status | Whether the breast cancer cells have the receptors for estrogen and progesterone (labeled ER-positive or PR-positive) or not — You may see hormone receptor-negative (HR-negative) if they don’t have those receptors or hormone receptor-positive (HR-positive) if they do | This gives doctors a clue as to what may work best and helps guide the type of treatment you get. |
| HER2 status | The amount of human epidermal growth factor receptor 2 protein, or HER2, on the surface of the breast cancer cells (They’re labeled HER2-negative or HER2-positive) | It can inform your treatment by pointing to how quickly the cancer may grow and spread. HER2-positive breast cancers may spread and grow faster, for example. |
| Tumor grade | How normal or abnormal cancer cells and their growth patterns look — scored 1-3 | This outlines how likely your breast cancer may be to grow and spread. |
| Tumor margins | How close cancer cells are to the rim of healthy tissue around a tumor — labeled negative, positive, or close | This helps your health care provider know if the entire tumor was removed or if you need more surgery. |
| Lymph node status | Whether the lymph nodes in your underarm area have cancer — labeled either positive or negative | This helps your doctor stage the breast cancer and decide which treatments you need. |
| Invasive vs. noninvasive | Tells you whether or not the abnormal cells have spread from their original location in the milk ducts or the glands and into nearby breast tissue, lymph nodes, or other parts of the body | This can sometimes tell you if the cancer is still in its original location and not life threatening or it’s spread to other tissues. |
| Lymphovascular invasion | Whether the cancer cells have entered lymph channels (lymphatic invasion) or small blood vessels (vascular invasion) | This may raise the chances that the cancer has or will spread to other parts of the body or that it may come back after treatment. |
