Understanding Your Pathology Report
If you are new to a DCIS diagnosis, then you most likely had a recent biopsy, and likely a core-needle biopsy performed by a radiologist. Tissue samples from your biopsy were sent to a lab and examined under a microscope by a pathologist, who then issued a pathology report based on his or her review of the slides.
Your pathology report is what provides your DCIS diagnosis. It also provides relevant information to help decide on the appropriate treatment for your DCIS.
Your pathology report should contain the following information:
- Which breast and where in your breast the biopsy was taken from.
- Where in your breast the DCIS calcifications or tumor is located.
- The nuclear grade of the DCIS, which can be low, intermediate, high, or some combination of these grades (i.e., low-intermediate). The nuclear grade is based how uniform or variable the cells are.
- The architectural pattern of the DCIS, which is the actual image the pathologist sees of the cells in the ducts. The major architectural patterns include cribriform, papillary, micropapillary, comedo and solid.
- Whether or not there is comedo necrosis, which is a collection of dead or dying tumor cells found in the ducts. Comedo necrosis is most commonly found in high-grade DCIS, which reflects the fact that the cells are growing quickly, outgrowing their blood supply, and dying. Comedo necrosis can be found in intermediate and low-grade DCIS, but it is far less common.
- Whether the DCIS is hormone-receptor positive or negative. If the DCIS has estrogen receptors, it will be called estrogen-receptor positive (ER+), and if it has progesterone receptors, it will be called progesterone-receptor positive (PR+). If the DCIS is both ER+ and PR+, it may be collectively referred to as hormone-receptor positive (HR+). If the DCIS has no estrogen or progesterone receptors, it will be called hormone-receptor negative (HR-). If the DCIS is ER+ and/or PR+, the pathology report will also comment on the strength of the positivity, which is determined through a staining process that takes place in the lab.
Collectively, these factors affect the risk that your DCIS will progress to invasive breast cancer.
In some cases, a DCIS diagnosis may arise from a pathologist’s review of a surgical specimen, a lump of fatty breast tissue that is obtained during breast surgery. This type of pathology report is more complicated and will contain more information because it is based on an analysis of more breast tissue. The pathology report on a surgical specimen will include all the information listed above, plus the addition of a synoptic summary. The synoptic summary will include important information about margin status (see more about margins below).
Understanding Margins
A surgical margin is a rim of healthy tissue that is removed along with the DCIS during a lumpectomy. Your surgeon may remove multiple margins during the surgery. A pathologist will review each margin under a microscope to see if there are any abnormal cells in it or near it. This helps your surgeon determine if all the DCIS has been removed. A clean or negative margin is one that contains no abnormal cells. If your margins are positive or “close”, your surgeon might recommend additional surgery or radiation.
The cosmetic outcome of a lumpectomy greatly depends on the amount of breast tissue that is removed. The goal is to remove enough tissue to ensure that all the DCIS taken out, but not so much that it results in a deformity or poor cosmetic result.
The current consensus among surgeons and radiation oncologists is that in most cases of DCIS, the optimal margin is 2mm.1 In other words, there should be no abnormal cells left within 2mm from the surface of the lumpectomy tissue specimen. (Note that this is a different margin size than is recommended for invasive breast cancer.)
Understanding Upgrade Rates and Microinvasion
In some cases, the pathology from a lumpectomy may show more advanced breast cancer, even though the initial core biopsy showed only DCIS. When this happens, the DCIS is said to be “upgraded”, either to DCIS with microinvasion (DCIS-MI), or less commonly, to invasive breast cancer.
Current studies put the percentage of DCIS cases that are upgraded, or the upgrade rate, at 10-20%. However, upgrade rates vary based on a number of clinical factors, including the extent of the original calcifications, the number of specimens removed during surgery, and the size of the needle used in the initial core needle biopsy. Most DCIS that is upgraded presents as high risk in the initial biopsy. In other words, different patients have different projected upgrade rates, depending on multiple factors. Your doctor should tailor any discussions about your chances of upgrade to the clinical presentation of your individual DCIS.
Additional Tests
DCIS patients may also consider having genomic testing done on their tissue samples to learn more about the DCIS and/or having genetic testing to look for genetic mutations that may predispose them to a higher risk of invasive breast cancer.
Genomic tests, also called tumor genomic assays, analyze the DCIS to see how active certain genes are. The genes’ activity level is believed to affect how the DCIS behaves, including how likely it is to grow and come back after treatment. Genomic tests are used to decide whether treatments after surgery would be beneficial. There are currently two genomic tests for DCIS – Oncotype DX Breast DCIS score and DCISionRT – that can be performed on tissue samples obtained from a lumpectomy or a biopsy. Both tests predict the risk of local recurrence and the potential benefit from radiation therapy after surgery.
Genetic testing looks for mutations – or changes – in genes that can increase the risk of developing breast cancer. Genetic testing can be performed on a blood or saliva sample that is sent to a lab for analysis. The most well-known genes that can mutate and raise the risk of breast cancer are BRCA1 and BRCA2. Inheriting a mutation in these genes puts a DCIS patient at a higher-than-average risk of developing invasive breast cancer. Genetic testing results can help guide your treatment decision.