Reading The Pathology Report - A Layperson's Guide To Understanding Your Breast Cancer Diagnosis

Patient Expert

"Have you got your pathology report yet?"
As a woman newly diagnosed with breast cancer, it seems that everything hinges on this all-important document. Will you have chemo? Is a lumpectomy "good enough?" And how about those hormone drugs: yes, or no?

Here's an example of what your pathology report might look like.

Your pathology report is compiled by a pathologist, a doctor who specializes in the microscopic examination of tissue to identify abnormalities. The report is based on the tumor or other cancerous tissue surgically removed from your breast. It includes a wealth of information used to make treatment decisions. It's the starting point of your journey through cancer, a map your oncologist relies upon to determine your best path to remission or a cure.

But with all of that why is the darned thing so hard to read and understand?
Because even though the pathology report is about you, it's not really for you. It's a summary of information passed among doctors; and let's face it, they don't speak the same language we do.

So you're left with a document that's literally used to make decisions in a life-or-death situation YOUR life-or-death situation and you can't understand it. What's a survivor to do?

First, if you don't already have it, ask for a copy of your pathology report. It's a simple matter for your oncologist to print it out for you. Once you have the report, you're ready to go over it, step by step, using this easy guide.

Pathology reports are written in different styles; and they may present the information in slightly different sequences. But in general, they'll contain the same information: a complete analysis of your breast cancer: type, aggressiveness, extent, and other attributes your oncologist will look at as a whole to make his or her best determination about your treatment.

Aside from the very first section the demographics, which list your name, your doctor's name, date of surgery, etc. the information may be presented in any order. So be prepared to flip around in your report to find the sections explained below.

Ready? Let's jump in.


First, make sure it's your pathology report. Seems silly, but it pays to check the very top of your report, which will list your name, date of birth, your doctor's name, and date of surgery/biopsy. If any of these facts are wrong, question your doctor. The last thing you need is the results of someone else's report.

Gross Description

This is the pathologist's description of what your tissue sample the tumor, and surrounding tissue looked like to the naked eye, as well as how it was prepared for microscopic examination. The size of the sample, weight, and other observations made by the pathologist (e.g., adipose tissue, fibrous tissue, stained with blue dye from sentinel node") are all noted.

Beware of misinterpreting the size of the sample as the size of the tumor: The size noted in this gross description is the entire sample, not just the tumor; the pathologist will indicate tumor size in the diagnosis section (see below).

While you may find the gross description interesting simply because it's a piece of your body being described, it really doesn't tell you much about your cancer. This is a part of your pathology report you can skim through.

Diagnosis (Final Pathologic Diagnosis, Pathologic Diagnosis)

Look for this heading: it indicates the section that'll interest you the most. The following sub-sections provide your oncologist with a wealth of detail about your particular cancer.

-Histologic type: This is the specific type of breast cancer you have. There are 14 identified types of breast cancer; the major ones are ductal carcinoma in situ (DCIS); lobular carcinoma in situ (LCIS); infiltrating ductal carcinoma (IDC); infiltrating lobular carcinoma (ILC); and inflammatory breast cancer (IBC).

The most important bit of information here is whether your cancer is "infiltrating" (or "invasive") vs. "in situ." Infiltrating means it's started to spread; not necessarily outside your breast, but beyond the milk ducts or lobules where it started. In situ means it hasn't yet spread outside the milk ducts or lobules. In situ cancers are often called "pre-cancers;" nevertheless, they're viewed as cancer and treated as such.

It's possible to have numerous types of breast cancer at the same time. Your report may read, for example, "IDC with DCIS." That simply means that there's a tumor in your breast identified as IDC; but there are other parts of your breast showing DCIS.Think of it like this: if you have a virus, you just plain have a virus, systemically. But if you've injured your hand, you could have a cut on your palm, a burn on your wrist, scraped knuckles" or all of the above. Breast cancer is like a hand injury: it can take numerous forms in various locations, often all at the same time.
-Histolopathologic grade, or tumor grade: This is a detailed examination of your cancer cells: what they look like, and how fast they're growing.

The Scarff-Bloom-Richardson (or simply Bloom-Richardson) scale is often used to determine grade. It consists of three parts, each with a scale of 1-3. The three parts are added together to give you a final grade, which will range from 3 (least aggressive, least serious) to 9 (most aggressive, most serious).

Sometimes, the grade will simply be given as 1, 2, or 3; or low, intermediate, or high. One (low) would be a Scarff-Bloom-Richardson score of 3 or under; 2 (intermediate) would be a score of 4-6; and 3 (high) would be a score of 7-9.

Here are the three things the pathologist will look for in your cancer cells:

_1. Nuclear grade: _ Cancer cells, like all cells, are run by a command center called the nucleus. Cells with a small, regularly shaped nucleus look more like normal cells; they'll be given a score of 1. Cells with a large, irregularly shaped nucleus will be given a score of 3. Cells in between those extremes receive a grade of 2. The larger and more irregular the nuclei in the cancer cells, the more aggressive and dangerous they are.

2. Mitotic rate: Simply, the number of cancer cells that are actively dividing. Fewer cells dividing = a score of 1; more cells, 2; even more cells, 3. The more cells dividing, the more aggressive the cancer.

3. Cellular differentiation: This refers to the ability of the cancer cells to build breast tissue like normal cells do. Cancer cells that aren't very aggressive act "normal" enough to do this, and receive a score of 1. Cancer cells that are aggressive and growing quickly lose their ability to build breast tissue; they're just too wild. They receive a score of 3.

So, say your cancer's nuclear grade is 2; its mitotic rate is 1; and its cellular differentiation is 3. That adds up to a score of 6 which might simply be called "grade 2" or "intermediate" on the SBR scale.

-Lymph node status: You'll probably see the term "axillary nodes" a lot on your pathology report. This refers to the lymph nodes under your arm, on the same side as your cancer. When you have your surgery (or sometimes before, if you're having chemotherapy prior to surgery), you'll have 2 or more lymph nodes removed, to see if they contain cancer.

Having "positive" lymph nodes (one or more nodes containing cancer) means your cancer is farther advanced than if there were no nodes involved.

The sentinel node is the lymph node closest to your cancer, and the first one that should show cancer cells, if the cancer is spreading outside the breast. Usually, the surgeon will remove two nodes: the sentinel node, and the one next to it. If the sentinel node shows cancer cells (a tiny tumor), the surgeon will go back and sample additional nodes.

The final pathology report will indicate how many nodes contained cancer; whether the cancer had spread outside any of the nodes; and how large the largest tumor was in any of the nodes. So it may read something like this:

Total number of nodes sampled: 3Number positive: 1 (one node contained cancer)
Extranodal (or extracapsular) extension: yes (the tumor has spread into the surrounding tissue)
Largest nodal deposit: 5mm (largest lymph node tumor is 5mm, about 1/60 of an inch)

Sometimes, you'll see figures something like this: 6/24. That means the surgeon removed 24 lymph nodes, and 6 contained cancer.

-Lymphovascular invasion, or angiolymphatic invasion: This tells whether or not the cancer in your breast has spread to the lymph system or blood vessels. "Identified" or "positive" means this has happened; and it generally signals a more aggressive or advanced cancer.


This is another part of your pathology report that's critical to determining treatment. Your oncologist will use the pathologist's information to determine if your cancer is stage 0, I, II, II, or IV, with 0 being a pre-cancer or in situ cancer; and IV being cancer that's spread to another part of your body, outside the breast and lymph nodes. Some oncologists will become more specific, and assign "a" or "b" to a certain stage, e.g., "IIb."

Stage is a big determinant in treatment; your doctor will rely on it heavily to decide whether or not you need chemotherapy; and if you have chemotherapy, how aggressive to make it. In general, the lower your stage of cancer, the less aggressive the treatment has to be, and the better your prognosis.

Yout pathology report may or may not include what stage your cancer is. Since it's the oncologist's determination to make, not the pathologist's, your oncologist may just discuss it with you, without it being in the report.

However, your cancer's stage is based heavily on three things: information about your tumor; information about your lymph nodes; and whether or not the cancer has moved (metastasized) into other parts of your body, beyond breast and underarm. And these three things will be in the pathology report.

The American Joint Committe on Cancer has developed a shorthand for determining these three aspects of your breast cancer, called TNM. Here's how it works:

**T = tumor size, the tumor diameter measured in centimeters; 1 centimeter = approx. 1/3 inch. Your T score can be any of the following:
TX: the tumor couldn't be accessed;
T0: no tumor;
Tis: in situ; tumor hasn't moved beyond its original ducts or lobules;
T1: less than 2cm;
T2: 2-5cm;
T3: more than 5cm;
T4: any size, but attached to the chest wall and spread to the chest lymph nodes.

N = palpable nodes, which indicates whether cancer has spread to the lymph nodes.
NX: the nodes couldn't be accessed;
N0: no spread;
N1: cancer has spread to the "movable" nodes in your armpit (axillary nodes) on the same side as your breast cancer;
N2: cancer has spread to the "attached" lymph nodes on the same side as your breast cancer; these nodes are attached to one another, or to other structures in your armpit;
N3: cancer has spread to the lymph nodes in your breast.

M = metastasis; whether the cancer has spread to other parts of your body beyond the breast and lymph nodes (distant metastasis).
MX: metastasis can't be assessed;
M0: no distant metastasis;
M1: distant metastasis.** So, here's how to interpret the jumble of numbers and letters you may see in your pathology report, that look something like this: pT2, pN1, M0. Or this: T2N1M0.

The interpretation of either of these is as follows:

-Your tumor is 2-5cm;
-Cancer has spread to the movable lymph nodes under your arm;
-There's no distant metastasis.

Don't be discouraged. This TNM information is perhaps the most confusing part of your pathology report. Just look for the capital letters T, N, and M; and the number or letter that follows them directly.

Your doctor will take this TNM information, combine your scores, and come up with your cancer stage. Here's a simplified rundown of breast cancer stages:

Stage 0: In situ cancer. No invasion/infiltration; no lymph node involvement; no metastasis. Often called "pre-cancer," because the cancer is entirely contained in the milk ducts or lobules where it started.

Remember, you may have both in situ and invasive cancer at the same time. Part of your breast may have one kind, and part another. Or one breast might have an IDC tumor, while the other   shows DCIS.

Stage I: Your tumor is less than 2cm; there's no lymph node involvement; and no metastasis.

Stage II: Your tumor is less than 2cm, but you have one or more lymph nodes involved; OR it's 2-5cm, either with or without lymph node involvement. There's no distant metastasis.

Stage III: Your tumor is up to 5cm, with involvement in one or more "fixed" nodes; OR itâ�™s less than 5cm, but has invaded your skin or chest wall (nodes involved or not). There's no distant metastasis.

Stage IV: Any size tumor; lymph node involvement or not; but distant metastasis has been identified. In other words, the cancer has spread from your breast to your bones, brain, liver, or lungs. Margins

If you had a lumpectomy, there'll be a part of your pathology report that talks about "margins" or "resection margins." These refer to the area of breast tissue surrounding the tumor that the surgeon removed.

The goal of any lumpectomy is to remove all of the tumor, yet as little of your breast as possible. That's why lumpectomy is currently referred to as "breast conservation surgery."

Your goal is to have "clear," "clean," or "negative" margins. That means the tissue surrounding the tumor shows no cancer cells.

The pathologist will note whether (and where) cancer cells are found, anywhere between the tumor and the far edges of the tissue sample. If cancer cells are found at the edge of the sample, you have "positive" margins. This signals the need for further surgery.

You may have several surgeries in order to obtain clear margins; if you've had several surgeries, and the pathologist is still finding cancer cells in the tissue, he or she may suggest a mastectomy. Comments or Other Findings

This is a space where the pathologist can include anything else of note. For instance, the report may mention the presence of fibrocystic disease a very common, benign condition that produces lumps in your breasts. Or the report could note an old scar, from a previous biopsy.

Your report may also note the presence of microcalcifications. These are tiny bits of calcium found wherever cells are dividing rapidly; it's   considered a first sign of breast cancer, pre-DCIS. The presence of microcalcifications (your report will say "identified" or "not identified") signals an area of your breast that didn't yet have cancer, but might have been developing it.

Special Tests

These may be headed "addendum," "prognostic report," or something similar. You'll know you're in this section when you see the results of two tests: hormone receptor status, and HER2.

-Hormone receptor status: Your report will indicate whether your cancer is estrogen and/or progesterone positive. It may simply say "positive," or it may give a percentage (5%, 15%, etc.) That percentage refers to what percentage of the cells examined were ER/PR-receptive.

This is one of the truly critical parts of your pathology report. It will determine the type of treatment you may receive for years to come. 70% of all breast cancers are termed hormone-receptive; that is, the cancer cells require one or both of two female hormones, estrogen and/or progesterone, to grow. Depriving them of these hormones via a variety of different drugs basically starves the cancer cells, and helps prevent cancer recurrence.

If you're ER/PR positive, it opens up a whole new avenue of treatment: hormone drug therapy. You'll probably be prescribed at least 5 years of tamoxifen or an aromatase inhibitor, two types of drugs that have both been proven to reduce recurrence in women with ER/PR-receptive cancer.

-Her2-neu; HER2/neu; Her2Neu (or simply HER2) status: The HER2 gene (also referred to as c-erbB-2, or similar) makes a protein that acts as a receptor on the surface of your cells. This receptor is sensitive to signals that tell the cell to grow. If the HER2 gene produces too much protein (too many receptors), the cell grows too quickly, which means cancer cells become overly aggressive and grow extra-fast.

There are currently two common ways to test for "HER2 over-expression" (you might see that term in your report).

-IHC (immunohistochemistry): This test is scored from 0 to 3; 0-1 are considered negative, while 2-3 are positive.

-FISH (fluorescent in situ hybridization): This is reported simply as a positive, or negative.

A positive result means your HER2 gene is indeed making too much protein. About 25% to 30% of breast cancers are HER2 positive. This means they're more aggressive and faster-growing then most breast cancers.

Women who are HER2 positive are generally prescribed the drug Herceptin, or Tykerb.

By now, you're hopefully at the end of your pathology report, and understand it a whole lot better than when you first puzzled over it. If there's anything you still don't understand, please post a comment here and let me know; I'll be glad to try to help you figure it out.