The technical wording on a pathology report can be confusing. Because it is prepared for health care providers, a pathology report is written in medical language. However, understanding the basic parts of the report can help you be better informed about your diagnosis.
Different pathology labs may use different terms to describe the same information. So, your report may not have the exact wording found here.
Needle biopsy reports may contain less information than surgical biopsy reports. Also, some tests are only done when invasive breast cancer or certain types of breast cancer are found. If your tissue is found to be free of cancer or if your diagnosis is ductal carcinoma in situ (DCIS), many of the sections described below will not appear on your report.
Diagnosis or final diagnosis
This is the most important section of the report. It gives the pathologist's final diagnosis and may include information on features of the tumor such as size, type, grade, hormone receptor status and HER2/neu status. If lymph nodes were removed, the status of these lymph nodes will also be included. These characteristics may appear grouped together or as separate sections, depending on your pathology report.
The microscopic description details what the pathologist saw and measured when he/she looked at the biopsy tissue under a microscope.
Tumor size is most often reported in centimeters or millimeters (1 inch = 2.54 centimeters = 25.4 millimeters). The best way to measure tumor size is under a microscope (especially for small tumors). When the length and width of the biopsy that contains cancer cells are measured (for example, 1.5 x 1.9 centimeters), the longer of the two is reported as the tumor size. This may be much smaller than the size of the tissue sample (the measurement of entire sample is reported in the gross description).
In general, the smaller the tumor, the better the prognosis tends to be.
Learn more about tumor size.
Non-invasive vs. invasive
Ductal carcinoma in situ (DCIS) is a non-invasive breast cancer (stage 0). The cancer cells are contained within the milk ducts (“in situ” means "in place").
Invasive breast cancer (also called infiltrating cancer) means the cancer cells inside of a milk duct or lobule have broken out and spread to nearby tissues.
For invasive breast cancers, the pathologist notes the shape of the cancer cells and assigns a histologic grade, using either a number system or words. Tumor grade describes the structure of the cells and is different from tumor stage. In general, the more the cancer cells look like normal breast cells, the lower the grade and the better the prognosis.
The most common grading system in current clinical practice is the Nottingham system:
Well-differentiated (cells look most similar to normal and are not growing rapidly)
Moderately-differentiated (cells look somewhat different than normal)
Poorly-differentiated (cells look very abnormal, and may be growing and spreading rapidly)
The nuclear grade describes how closely the nuclei of cancer cells look like the nuclei of normal breast cells. In general, the higher the grade, the more abnormal the nuclei are and the more aggressive the tumor cells tend to be. The nuclear grade is a part of overall tumor grade.
Learn more about histologic grading and prognosis.
Hormone receptor status
Hormone receptors are proteins found inside some cancer cells. When hormones (estrogen and progesterone) attach to these receptors, they make the cancer cells grow.
- Estrogen and progesterone receptor-positive (ER+ and PR+) tumors have many hormone receptors
- Estrogen and progesterone receptor-negative (ER- and PR-) tumors have few or no hormone receptors
The hormone receptor status of your tumor helps guide your treatment plan. If your tumor is ER+ and/or PR+, treatments that prevent the cancer cells from getting the hormones they need to grow (hormone therapies, such as tamoxifen or aromatase inhibitors) may stop tumor growth. Tumors that are ER- and PR- are not treated with hormone therapies.
The American Society for Clinical Oncology and the National Comprehensive Cancer Network recommend hormone receptor testing for all tumors.
Learn more about hormone receptor status and prognosis.
Learn more about hormone therapies.
HER2/neu (human epidermal growth factor receptor 2), also called ErbB2, is a protein that appears on the surface of some breast cancer cells. It is an important part of the cellular pathway for growth and survival.
- HER2/neu-positive (HER2+) tumors have many HER2/neu genes inside the cancer cells (also called HER2/neu over-expression) and a large amount of HER2/neu protein on the surface of the cancer cells
- HER2/neu-negative (HER2-) tumors have few HER2/neu genes inside the cancer cells and little or no HER2/neu protein on the surface of the cancer cells
About 15 to 20 percent of breast cancers are HER2+ [30-31]. These breast cancers tend to be more aggressive than other tumors.
HER2/neu status helps guide your treatment plan. HER2+ cancers can benefit from trastuzumab (Herceptin) therapy, which directly targets the HER2/neu receptor. This type of therapy is not used to treat HER2- cancers.
Both the American Society for Clinical Oncology and the National Comprehensive Cancer Network recommend HER2/neu testing for all tumors. HER2/neu status can be determined in two ways:
- Immunohistochemistry (IHC) testing which detects the amount of HER2/neu protein on the surface of the cancer cells
- Fluorescence in situ hybridization (FISH) testing which detects the number of HER2/neu genes in the cancer cells
Most often, IHC is the first test and if the score is +2 (or borderline), the tumor is sent for FISH testing to confirm the status.
Results of an IHC test
Score is 0 or +1
Tumor is HER2-
Score is +2
Results are unclear and should be confirmed by FISH
Score is +3
Tumor is HER2+
Results of a FISH test
The tumor is HER2+
The tumor is HER2-
Learn more about HER2/neu status and prognosis.
Learn more about treatment with trastuzumab (Herceptin).
During a surgical biopsy, a rim of normal breast tissue (called a margin) surrounding the suspicious area is taken out to be sure the entire tumor was removed. The pathologist looks at the margins and decides whether or not they contain cancer cells.
Positive (also called "involved") margins
- The margins along the edge of the biopsy contain cancer cells.
- More surgery may be needed to obtain clear margins. (This should be discussed with your surgeon.)
- Sometimes it is not possible to get a clear margin due to its location (for example, if it is at the chest wall).
- The cancer cells approach, but do not touch the edge of the biopsy.
- More surgery may be needed. (This should be discussed with your surgeon.)
Negative (also called "not involved", "clear" or "clean") margins
- The margins do not contain cancer cells.
- No more surgery is needed.
Vascular invasion (blood vessel invasion/angiolymphatic invasion/lymphovascular invasion)
Vascular invasion occurs when cancer cells enter blood vessels or lymph channels. This may suggest a more aggressive tumor.
Lymph node status
If lymph nodes were removed during the biopsy, the pathologist determines whether or not the lymph nodes in the underarm area (axillary nodes) contain cancer.
- Lymph node-negative means the lymph nodes do not contain cancer.
- Lymph node-positive means the lymph nodes contain cancer.
In general, lymph node-negative breast cancers have a better prognosis than lymph node-positive breast cancers.
Learn more about lymph node status and prognosis.
Other information on a pathology report
The following items are included on all pathology reports, but do not impact prognosis or treatment.
This section of the report has basic information including your name, medical record number, date of birth, age and sex, date of the biopsy and name of the health care provider who ordered the report (most often your surgeon). It is a good idea to check all this information to make sure you have the correct pathology report.
Specimen(s) received (specimen source/specimen submitted)
This section records the location in the breast where the biopsy sample(s) was removed. It may simply state left or right breast, or may give more detail. It also includes the date the pathologist received the tissue.
Procedure (description of procedure)
This is a description of the type of biopsies used to remove the tissue sample and lymph nodes (if lymph nodes removed).
- Needle biopsy or surgical biopsy for tumor tissue
- Sentinel node biopsy or axillary dissection for lymph nodes
Learn more about biopsies.
Clinical history (clinical information/clinical diagnosis/pre-operative diagnosis)
The clinical history describes the initial diagnosis before the biopsy and sometimes, a brief summary of your symptoms. If there was a prior biopsy, the pathologist often will review this tissue so he/she can distinguish the recurrence of a past tumor from a new breast cancer. The location of the tumor biopsy is also noted (for example, left or right breast).
Gross description (macroscopic description)
One of the first things the pathologist does when he/she receives the biopsy tissue is to take measurements and record a description of the tissue as it appears to the naked eye (without a microscope). This gross description may include the size, weight, color, texture or other features of the tissue and any other visual notes.
If there are multiple samples, there is often a separate gross description section for each sample. In these cases, the pathologist assigns a reference number or letter to each tissue sample to avoid confusion.
The gross description also includes information on how the sample was handled once it reached the pathologist.
The pathologist who is responsible for the contents signs and dates the report (most often, electronically).
Information sometimes seen on a pathology report
The following items do not impact prognosis or treatment and may not appear on your report. Some of these tests are only done for certain diagnoses. Others are not routinely done because they do not predict prognosis over and above standard measures or because they are not reliable measures for all tumors.
Immunohistochemistry (IHC) for prognostic markers
Beyond HER2/neu status testing, IHC can detect other molecular markers that may give information on prognosis.
Proliferation rate (Ki-67, MIB1)
The proliferation rate represents the percentage of cancer cells that are actively dividing. In general, the higher the proliferation rate, the more aggressive the tumor tends to be.
Proliferation rate could be a good predictor of prognosis. However, there are issues related to its measurement, so it is not widely used by health care providers to make treatment decisions.
The Ki-67 test is a common way to measure proliferation rate. MIB1 is the antibody most often used to label the Ki-67 antigen. You may see these terms on your pathology report. A higher value shows a higher proliferation rate.
Learn more about understanding your pathology report.
The College of American Pathologists’ www.mybiopsy.org website also has information on the contents of a pathology report.