Hearing that something suspicious was detected on your mammogram or breast ultrasound can be concerning. Most likely, you were told the next step is to follow up with a biopsy. But what exactly is a biopsy, and what will the doctor discover from the biopsy results?
What is a Breast Biopsy?
A breast biopsy involves taking a small sample of breast tissue to examine it under a microscope by a pathologist. Up to this point, you’ve probably had a few different tests, such as a mammogram and possibly an MRI or ultrasound, that suggest the presence of cancer. A biopsy is the only definitive way to confirm whether a breast lump is noncancerous (benign) or cancerous (malignant).
The type of biopsy you have depends on several factors, such as the size and location of the lump, the number of abnormalities present, your overall health, and your personal preferences. The most common types of biopsy used for breast cancer diagnosis are:
- Fine-needle aspiration biopsy: A thin needle removes a small amount of cells or fluid from a breast lump. Ultrasound images may guide this procedure if the lump can’t be felt.
- Core needle biopsy: A wider needle removes a larger breast tissue or fluid sample. This is usually guided by 3-D mammogram imagery, an ultrasound, or an MRI scan to guide the surgeon to the lump's exact location.
- Surgical biopsy: In some cases, surgery is used to remove the tissue sample. This can be an incisional biopsy, which removes part of the tumor, while excisional biopsies remove it all. The surgeon is typically guided to the exact location of the lump using a pellet placed inside the breast that can be detected with a special tool in the operating room. Wire-guided biopsies are also used, with the placement of a wire that shows the surgeon exactly where to look for the lump.
- Lymph node biopsy: If the tumor appears to be more advanced based on its size and location, your doctor may suggest you have lymph nodes tested for the presence of breast cancer cells. Several lymph nodes are removed from under the arm, closest to the lump, and then tested for cancer.
Understanding the Results of Your Breast Biopsy
After completing a breast biopsy, the samples are sent to a pathologist. This doctor will review the cells under a microscope and then create a comprehensive report detailing the important characteristics of the sample. This includes the size, weight, and color of the tissue, as well as anything they notice about the cells under a microscope, protein tests, cell growth rate, and a diagnosis or summary of the findings. It will also likely indicate whether the sample is hormone receptor-positive.
Interpreting Benign Breast Biopsy Results
The good news is that most breast biopsies produce benign results. However, even if your report comes back cancer-free, you will still see certain terms describing these non-cancerous changes in your breast, such as:
- Adenosis
- Cysts
- Duct ectasia
- Sclerosing adenosis (SA)
- Apocrine metaplasia
- Columnar cell change (CCC)
- Columnar cell hyperplasia (CCH)
- Fibrocystic breast changes
- Collagenous spherulosis (CS)
- Papillomatosis
- Columnar alteration with prominent apical snouts and secretions (CAPSS)
Unless you experience symptoms, you likely won't need treatment. Most benign breast conditions also do not increase your risk of future breast cancer. Discuss any concerns about your benign breast biopsy results with your doctor.
Interpreting Cancerous Breast Biopsy Results
If your breast biopsy results confirm the presence of cancer cells, your pathology report will provide details about the specific characteristics of the tumor. This information is crucial for your cancer care team to develop a treatment plan. Here is some of the information you may see in your pathology report and what it means:
Type of Breast Cancer: Is Invasive or Noninvasive?
The type of breast cancer typically refers to where it started and whether it’s invasive or noninvasive.
Noninvasive (in situ) breast cancer is contained in the milk duct where it started. The report will list this as ductal carcinoma in situ (DCIS), which is considered a precancer or stage 0 breast cancer.
Invasive (infiltrating) breast cancer has invaded nearby tissue and spread beyond where it initially started in either a milk duct, called invasive ductal carcinoma, or in the lobe of the breast, called invasive lobular carcinoma (ILC).
In addition to the information above, your biopsy may have found cancer cells for one of these types of breast cancer:
- Inflammatory breast cancer: A rare type of breast cancer with symptoms of swelling or reddening skin and typically no lump.
- Paget’s disease: A rare type of cancer found in the nipple and areola.
- Phyllodes tumors: These tumors originate in the connective tissue of the breast. Most are benign, but they can be malignant.
Read our related blog: What is Inflammatory Breast Cancer?
Breast Cancer Grade
The cancer grade measures how different the cancer cells look compared to normal cells and how fast they are growing:
- Grade 1: Cancer cells look slightly different from normal cells and usually grow slowly.
- Grade 2: Cancer cells look noticeably different from normal cells and grow at a faster rate.
- Grade 3: Cancer cells look significantly different from normal cells and are growing at a faster rate.
Higher-grade breast cancers will likely require more treatments to treat them successfully compared to lower-grade cancers.
Hormone Receptor Positive or Negative
The cells in your breast tissue sample will be examined for hormone receptors. Proteins on the cancer cells can attach to estrogen or progesterone hormones, causing the cancer cells to grow faster. If the cancer tests positive for these hormone receptors, it means the cancer is using hormones to grow, and hormone therapy may be a suitable treatment option.
Your pathology report may list hormone receptor status information in the following ways:
- The term "positive" indicates that there are receptors for estrogen, progesterone, or both. If the result is negative, the cancer does not have hormone receptors.
- A percentage indicates how many cells test positive for receptors.
- An Allred score combines the percentage of cells with receptors and how well the receptors appear. This score ranges from 0 to 8, with a higher number indicating more easily visible receptors.
Learn how hormone receptor status affects breast cancer treatment.
HER2 Status
HER2 is a protein that controls breast cell growth. If the biopsy report is “positive” for HER2, the cancer is using this protein to grow. If your pathology report shows a HER2 designation of "equivocal," it means your cancer's HER2 status is uncertain. A second test may be recommended to determine your cancer's HER2 status. If your cancer expresses HER2 on one test but not the other, it may be classified as HER2-low.
Treatment Decisions Are Based on Biopsy Results
The biopsy report, along with imaging and lymph node involvement reports, will determine the stage of cancer ranging from 0 to IV (4). The treatments recommended are specific to the type of breast cancer, the stage, and the grade. Your breast cancer oncologist and surgeon will meet and discuss the best next steps for you. Feel free to ask questions and discuss what’s next for you.
Expert Breast Cancer Care in the Portland-Vancouver Area
If you or a loved one had biopsy results that confirmed a breast cancer diagnosis, the team at Compass Oncology is here to support you every step of the way. It’s time to choose your medical oncologist to lead your treatment team.
Schedule a consultation with a breast cancer specialist at one of our cancer centers in the Portland, Oregon, or Vancouver, Washington areas to learn more about a personalized treatment plan. We can also provide a second opinion to help you make the best decisions for you.
