DCIS (ductal carcinoma in situ) is the most common form of non-invasive breast cancer and is considered stage 0 cancer. While DCIS isn’t considered life threatening, it does increase the risk of developing invasive breast cancer later in life.
Imaging studies such as mammogram and MRI, often along with physical exams of the breast, can lead doctors to suspect that a person has breast cancer. However, the only way to know for sure is to take a sample of tissue from the suspicious area and examine it under a microscope.
A biopsy is a small operation done to remove tissue from an area of concern in the body. The tissue sample is examined by a pathologist (a doctor who specializes in diagnosing disease) to see if cancer cells are present. If cancer is present, the pathologist then looks at the cancer’s characteristics.
Biopsy is usually a simple procedure. In the United States, only about 20% of the women who have breast biopsies turn out to have cancer.
A study looked to see how accurate pathologists’ interpretations of breast biopsy samples were.
The results suggest that pathologists disagree most often when diagnosing DCIS and atypia (atypia is excessive growth of abnormal cells).
The research was published online on March 22, 2016 by the Annals of Internal Medicine. Read the abstract of “Variability in Pathologists’ Interpretations of Individual Breast Biopsy Slides: A Population Perspective.”
To do the study, the researchers analyzed the results of the B-Path study using U.S. population-adjusted estimates. The researchers estimated the probability that one pathologist’s reading of a single breast biopsy slide would be confirmed by the combined results of readings by three other expert pathologists of the same slide. So for example, if a pathologist read a single slide from a woman’s biopsy as DCIS, how likely would it be that the same slide would get the same diagnosis from a panel of three expert pathologists?
The researchers found that pathologists were likely to agree when diagnosing invasive breast cancer. Pathologists were less likely to agree when diagnosing DCIS and atypia:
- pathologists disagreed about 62% of the time when diagnosing atypia
- pathologists disagreed about 30% of the time when diagnosing DCIS
It’s important to know that the design of this study didn’t take into account how pathologists interpret slides and make diagnoses in the real world.
In the real world, pathologists can look at a number of slides from each biopsy. If one slide isn’t enough to make a definitive diagnosis, the pathologist can look at others. In the real world, pathologists also regularly consult with each other on diagnoses, especially if there are questions or uncertainty. In the real world, a pathologist who is uncertain about the results of a biopsy can tell a woman’s doctor that the biopsy results are unclear and that a second opinion is needed. The biopsy slides can then be sent to another pathologist to read.
If you’re having a biopsy because a mammogram or other test found a suspicious area in your breast, you’ll receive the results in a pathology report. If you have questions about anything in your pathology report, ask your doctor or nurse navigator to explain these areas to you. If your pathology report diagnoses you with DCIS or atypia or is in unclear in any way, you may want to ask for a second opinion. If you’re thinking about a second pathology opinion, call your insurance company to make sure this service is covered. Sometimes, insurance companies only pay for a physician to give a second opinion about your original pathology results.
When you and your doctor have the most accurate information, you can make the best treatment decisions for you and your unique situation.
For more information on when and how to get a second opinion, visit the Breastcancer.org Getting a Second Opinion pages.