What percentage of biopsies are malignant?
Diagnosis — Breast cancer in women
See a GP as soon as possible if you notice any symptoms of breast cancer, such as an unusual lump in your breast or any change in the appearance, feel or shape of your breasts.
The GP will examine you. If they think your symptoms need further assessment, they’ll refer you to a specialist breast cancer clinic.
Tests at a breast cancer clinic
If you have suspected breast cancer, either because of your symptoms or because a mammogram has shown an abnormality, you’ll be referred to a specialist breast cancer clinic for further tests.
Mammogram and breast ultrasound
If you have symptoms and have been referred to a specialist breast unit by a GP, you’ll probably be invited to have a mammogram, which is an X-ray of your breasts. You may also need an ultrasound scan.
If cancer was detected through the NHS Breast Screening Programme, you may need another mammogram or ultrasound scan.
Your doctor may suggest that you only have a breast ultrasound scan if you’re under the age of 35. This is because younger women have denser breasts, which means a mammogram is not as effective as ultrasound in detecting cancer.
Ultrasound uses high-frequency sound waves to produce an image of the inside of your breasts, showing any lumps or abnormalities.
Your breast specialist may also suggest a breast ultrasound if they need to know whether a lump in your breast is solid or contains liquid.
A biopsy is where a sample of cells is taken from your breast and tested to see if it’s cancerous.
You may also need a scan and a needle test on lymph nodes in your armpit (axilla) to see whether these are also affected.
Biopsies can be taken in different ways, and the type you have will depend on what your doctor knows about your condition.
Needle aspiration may be used to test a sample of your breast cells for cancer or drain a small fluid-filled lump (benign cyst).
Your doctor will use a small needle to extract a sample of cells, without removing any tissue.
Needle biopsy is the most common type of biopsy. A sample of tissue is taken from a lump in your breast using a large needle.
You may have a local anaesthetic, which means you’ll be awake during the procedure, but your breast will be numb.
Your doctor may suggest that you have a guided needle biopsy, usually guided by ultrasound or X-ray, or sometimes MRI, to obtain a more precise and reliable diagnosis of cancer.
This can also distinguish it from any non-invasive change, particularly ductal carcinoma in situ (DCIS).
Vacuum-assisted biopsy, also known as mammotome biopsy, is another type of biopsy.
During the procedure, a needle is attached to a gentle suction tube, which helps to obtain the sample and clear any bleeding from the area.
Want to know more?
- Breast Cancer Now: What to expect at a breast clinic appointment
- Cancer Research UK: diagnosing breast cancer
- Macmillan Cancer Support: how breast cancer in women is diagnosed
Further tests for breast cancer
If a diagnosis of breast cancer is confirmed, more tests will be needed to determine the stage and grade of the cancer, and the best method of treatment.
Scans and X-rays
A CT scan, chest X-ray and liver ultrasound scan may be needed to check whether the cancer has spread.
An MRI scan of the breast may be needed to clarify the results or assess the extent of the condition within the breast.
If your doctor thinks the cancer could have spread to your bones, you may need a bone scan.
Before having a bone scan, a substance containing a small amount of radiation known as an isotope will be injected into a vein in your arm.
This will be absorbed into your bone if it’s been affected by cancer. The affected areas of bone will show up as highlighted areas on the bone scan.
Tests to determine specific types of treatment
You’ll also need tests that show whether the cancer will respond to specific types of treatment.
The results of these tests can give your doctors a more complete picture of the type of cancer you have and how to treat it.
In some cases, breast cancer cells can be stimulated to grow by hormones that occur naturally in your body, such as oestrogen and progesterone.
If this is the case, the cancer may be treated by stopping the effects of the hormones or by lowering the level of these hormones in your body. This is known as hormone therapy.
During a hormone receptor test, a sample of cancer cells will be taken from your breast and tested to see if they respond to either oestrogen or progesterone.
If the hormone is able to attach to the cancer cells using a hormone receptor, they’re known as hormone-receptor positive.
While hormones can encourage the growth of some types of breast cancer, other types are stimulated by a protein called human epidermal growth factor receptor 2 (HER2).
These types of cancers can be diagnosed using a HER2 test and are treated with medicine that blocks the effects of HER2. This is known as targeted therapy.
Want to know more?
- Cancer Research UK: tests on breast cancer cells
Stage and grade of breast cancer
Stage of breast cancer
When breast cancer is diagnosed, your doctors will give it a stage. The stage describes the size of the cancer and how far it has spread, and is used to predict the outlook.
Ductal carcinoma in situ (DCIS) is sometimes described as stage 0. Other stages of breast cancer describe invasive breast cancer and include:
- stage 1 – the tumour measures less than 2cm and the lymph nodes in the armpit are not affected. There are no signs that the cancer has spread elsewhere in the body
- stage 2 – the tumour measures 2 to 5cm, the lymph nodes in the armpit are affected, or both. There are no signs that the cancer has spread elsewhere in the body
- stage 3 – the tumour measures 2 to 5cm and may be attached to structures in the breast, such as skin or surrounding tissues, and the lymph nodes in the armpit are affected. There are no signs that the cancer has spread elsewhere in the body
- stage 4 – the tumour is of any size and the cancer has spread to other parts of the body (metastasis)
This is a simplified guide. Each stage is divided into further categories: A, B and C. If you’re not sure what stage you have, talk to your doctor.
TNM staging system
The TNM staging system may also be used to describe breast cancer, as it can provide accurate information about the diagnosis:
- T – the size of the tumour
- N – whether the cancer has spread to the lymph nodes
- M – whether the cancer has spread to other parts of the body
Grades of breast cancer
The grade describes the appearance of the cancer cells.
- low grade (G1) – the cells, although abnormal, appear to be growing slowly
- medium grade (G2) – the cells look more abnormal than low-grade cells
- high grade (G3) – the cells look even more abnormal and are more likely to grow quickly
Want to know more?
- Breast Cancer Now: cancer grades and size
- Cancer Research UK: the number stages of breast cancer
- Cancer Research UK: TNM breast cancer staging
Page last reviewed: 28 October 2019
Next review due: 28 October 2022
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Core-Needle Biopsy for Breast Abnormalities
Archived: This summary is based on a report that is greater than 3 years old. Findings should not be considered current.
This is a summary of a systematic review update evaluating the current evidence regarding the comparative effectiveness of core-needle biopsy and open surgical biopsy for diagnosing breast lesions. The systematic review summarizes the accuracy and possible harms of various core-needle biopsy methods. It does not discuss fine-needle aspiration. The systematic review included 316 clinical studies published through December 16, 2013. This summary is provided to assist in informed clinical decisionmaking. However, reviews of evidence should not be construed to represent clinical recommendations or guidelines.
About one in eight women in the United States will develop invasive breast cancer during her lifetime. Approximately 290,000 new cases of breast cancer are diagnosed each year in the United States, and more than 230,000 of these cases are invasive breast cancer.
Routine screening with physical examination and mammography is widely used in the United States. Breast abnormalities can also be found through self-examination or when symptoms arise. Suspicious mammographic findings may require a biopsy for diagnosis. More than 1 million women have breast biopsies each year in the United States. About 20 percent of these biopsies yield a diagnosis of breast cancer.
Open surgical biopsy removes suspicious tissue through a surgical incision. This procedure requires either a general or local anesthetic and closure of the incision with sutures.
Core-needle procedures, which remove a small tissue sample through a very small incision, have been widely adopted as a less-invasive biopsy option. Core-needle biopsy uses a hollow-core needle, ranging in size from 11 to 16 gauge, to remove one or more pieces of breast tissue. The operator either aims the needle directly at the area of a palpable lesion (freehand biopsy) or uses an imaging technique to localize the target lesion. The imaging techniques include stereotactic radiography, ultrasound, and magnetic resonance imaging (MRI). Techniques used to extract the biopsy specimen include an automated device and vacuum assistance. No consensus has been reached about which of these techniques is preferable for attaining the highest accuracy and lowest rate of harm with core-needle breast biopsies.
Currently, more than half of all breast biopsies use a core-needle technique. In light of the widespread use of core-needle methods, it is important to understand their accuracy and possible harms when compared with those of open surgical biopsy.
Clinical Bottom Line
- The sensitivity of core-needle biopsies performed using either stereotactic or ultrasound guidance is 97–99 percent. [evidence medium]
- The underestimation probability of invasive cancer in core-needle biopsies read as noninvasive neoplastic lesions (such as ductal carcinoma in situ) or high-risk lesions (such as atypical ductal hyperplasia) ranges from about 10 percent to slightly more than 45 percent, depending on the core-needle method used. [evidence low]
- The rate of complications (hematoma formation, bleeding, and infection) after core-needle biopsy is less than 1.5 percent (median). [evidence low]
Strength of Evidence Scale*
High: [evidence high]
High confidence that the evidence reflects the true effect. Further research is very unlikely to change our confidence in the estimate of effect.
Moderate: [evidence medium]
Moderate confidence that the evidence reflects the true effect. Further research may change our confidence in the estimate of effect and may change the estimate.
Low: [evidence low]
Low confidence that the evidence reflects the true effect. Further research is likely to change our confidence in the estimate of effect and is likely to change the estimate.
Insufficient: [evidence insufficient]
Evidence is either unavailable or does not permit a conclusion.
*Owens DK, Lohr KN, Atkins D, et al. AHRQ series paper 5: grading the strength of a body of evidence when comparing medical interventions—Agency for Healthcare Research and Quality and the Effective Health-Care Program. J Clin Epidemiol. May 2010;63(5):513-23. PMID: 19595577.
Accuracy of Core-Needle Breast Biopsy
Because core-needle biopsy samples only part of the suspicious tissue, a lesion could be misclassified as benign, high risk, or noninvasive when invasive cancer is in fact present in unsampled areas (a false-negative biopsy). Open surgical biopsy samples most or all of the lesion, so it is considered to have a smaller risk of misclassification. However, open procedures may carry a greater risk of complications, such as bleeding or infection, when compared with core-needle biopsy procedures. Therefore, if core-needle biopsy is also highly accurate, it may be preferable to open surgical biopsy.
Sensitivity is an estimate of the proportion of all cases of cancer that are identified by a diagnostic test (in this case, core-needle biopsy). Research studies designed to measure the sensitivity of core-needle biopsy generally use a second biopsy (with the open surgical method) or clinical followup over time to detect cancerous lesions that were missed.
All open surgical biopsy specimens read as invasive breast cancer are considered true-positive readings. Occasionally, a core-needle biopsy removes the entire target lesion, thereby rendering subsequent open surgical biopsies unable to confirm the findings of the original core-needle biopsy. In such cases of core-needle biopsy-diagnosed malignancy, the core-needle biopsy results are considered to be true positive.
The clinical technique used to perform a core-needle breast biopsy was found to influence the sensitivity of the procedure (see Tables 1 and 2). The freehand technique has lower sensitivity than biopsies using either stereotactic radiography or ultrasound for guidance but has similar specificity. Stereotactically guided automated techniques are associated with a lower sensitivity and a higher specificity when compared with stereotactically guided vacuum-assisted methods. Evidence is insufficient to determine the accuracy of MRI-guided core-needle biopsies.
Studies on the accuracy of core-needle breast biopsies were deemed to have moderate to high risk of bias because of characteristics related to their design and conduct, which did not permit strong conclusions. Information on study- or population-level characteristics that could be modifiers of test performance was inadequate. The size, location, or imaging characteristics of a lesion may influence the choice of one breast biopsy technique over another. However, research studies have not included sufficient information about these characteristics to determine their impact on biopsy accuracy.
|Biopsy Method||Sensitivity (95% CrI)||Specificity (95% CrI)||Strength of Evidence|
|95% CrI = 95-percent credible interval|
|Freehand||0.91 (0.80 to 0.96)||0.98 (0.95 to 1.00)||[evidence low]|
|Ultrasound, automated||0.99 (0.98 to 0.99)||0.97 (0.95 to 0.98)||[evidence medium]|
|Ultrasound, vacuum-assisted||0.97 (0.92 to 0.99)||0.98 (0.96 to 0.99)||[evidence medium]|
|Stereotactically guided, automated||0.97 (0.95 to 0.98)||0.97 (0.96 to 0.98)||[evidence medium]|
|Stereotactically guided, vacuum-assisted||0.99 (0.98 to 0.99)||0.92 (0.89 to 0.94)||[evidence medium]|
|Comparison||Finding||Strength of Evidence|
|Ultrasound, automated vs. vacuum-assisted||No difference in sensitivity or specificity.||[evidence low]|
|Stereotactically guided, automated vs. vacuum-assisted||Sensitivity of vacuum assistance is better.||[evidence low]|
|Specificity of automation is better.||[evidence low]|
Misclassification of Biopsy Results
Some biopsies are read as noninvasive neoplastic lesions. These neoplastic lesions include ductal carcinoma in situ and high-risk lesions, such as lobular carcinoma in situ, atypical lobular hyperplasia, and atypical ductal hyperplasia.
There is concern that core-needle breast biopsies may miss areas of invasive cancer in specimens in which the lesion is predominantly noninvasive.
|Biopsy Method||Average Underestimation Probability of DCIS (95% CrI)||Average Underestimation Probability of High-Risk Lesion* (95% CrI)||Strength of Evidence|
|95% CrI = 95-percent credible interval; DCIS = ductal carcinoma in situ |
* The most common reading of high-risk lesions is atypical ductal hyperplasia.
|Ultrasound, automated||0.38 (0.26–0.51)||0.25 (0.16–0.36)||[evidence low]|
|Ultrasound, vacuum-assisted||0.09 (0.02–0.26)||0.11 (0.02–0.33)||[evidence low]|
|Stereotactically guided, automated||0.26 (0.19–0.36)||0.47 (0.37–0.58)||[evidence low]|
|Stereotactically guided, vacuum-assisted||0.11 (0.08–0.14)||0.18 (0.13–0.24)||[evidence low]|
|Other methods||Insufficient evidence||Insufficient evidence||[evidence insufficient]|
Complications and Pain
Clinically significant complications occur in a minority of women who undergo open surgical biopsies. The rate of hematomas is 2–10 percent, and the rate of infections is 4–6 percent. The rate of any complication is substantially lower with core-needle biopsies (see Table 4).
Pain was assessed heterogeneously across studies, which did not permit conclusions about pain occurring after biopsy procedures.
- Vasovagal reactions are more common among patients who sit during a biopsy procedure. [evidence low]
- Vacuum-assisted core-needle breast biopsy procedures are associated with slightly increased rates of bleeding and hematoma formation than biopsies performed with an automated device. [evidence low]
Applicability of Findings
The existing evidence base on core-needle biopsy of breast lesions in women at average risk of breast cancer is applicable to clinical practice in the United States. The average age of women in the studies was similar to that of women undergoing breast biopsy in the United States, and the indications were similar to the prevalent indications in clinical practice (i.e., mammographic findings of suspicious lesions). The applicability of findings to women at high risk of breast cancer is uncertain because few studies explicitly reported on groups of patients at high baseline risk of breast cancer and because comparisons of test performance between subgroups of women produced imprecise results.
The information in this summary is based on Dahabreh IJ, Wieland LS, Adam GP, Halladay C, Lau J, Trikalinos TA. Core Needle and Open Surgical Biopsy for Diagnosis of Breast Lesions: An Update to the 2009 Report. Comparative Effectiveness Review No. 139. (Prepared by the Brown Evidence-based Practice Center under Contract 290-2012-00012-I.) AHRQ Publication No. 14-EHC040-EF. Rockville, MD: Agency for Healthcare Research and Quality; September 2014.
The summary of the 2009 review was prepared by the John M. Eisenberg Center for Clinical Decisions and Communications Science when located at Oregon Health & Science University, Portland, OR. Based on the 2014 review, the summary was updated by the Eisenberg Center located at Baylor College of Medicine, Houston, TX.
A Thorough Guide to Understanding Breast Biopsy Results
While needing a breast biopsy can be scary, it does not necessarily mean you have cancer.
In fact, about 4 out of 5 breast biopsy results are benign, meaning the tissue is normal and cancer-free. Breast biopsies are typically performed after an abnormality has been detected on an imaging test, such as a mammogram, ultrasound, or MRI scan. During a biopsy procedure, small samples of tissue are taken from the suspicious area. The samples are then examined under a microscope to check for the presence of cancer cells.
Following your exam, you will receive a pathology report detailing your breast biopsy results. Oftentimes, the results can be a bit overwhelming to understand — especially after an anxious waiting period. To help guide you through your report, here’s a comprehensive list of breast biopsy diagnoses and their definitions.
Benign Breast Biopsy Results
Benign means not cancer. When your biopsy result is benign, no other treatment is usually needed.
- Cysts are pockets of liquid in the breast and are very common. Cysts can be large or small and may change in size. If a cyst is large or painful, it may be drained or removed.
- Fat necrosis is one of the ways that the breast heals after an injury. The injury may be something minor that you may not even remember. Fat necrosis may show up at any time, even years after the injury. No treatment is needed.
- Fibroadenomas are growths of solid tissue in the breast. They may grow slowly. If a fibroadenoma is large or is causing discomfort, it may be taken out.
- Fibrocystic changes are areas of fibrous tissue mixed with cysts in the breast. Usually, no treatment is needed.
- Lymph nodes are a normal part of your body that are found in your underarm and in your breast. They may enlarge when your body is fighting an infection or if a cancer has spread to your lymph nodes. If your lymph node is benign, there is no cancer in it.
- Pseudoangiomatous stromal hyperplasia is a harmless type of growth of tissues found in the breast. Usually, no treatment is needed. The area may be taken out if is large or is causing discomfort.
- Here are some other results that are benign and no treatment is usually needed: apocrine metaplasia, columnar cell change, focal stromal fibrosis, inflammation, reactive changes, sclerosing adenosis, usual ductal hyperplasia**
Increased Risk Breast Biopsy Results
Biopsy results which show “increased risk” are not cancer. However, this result could mean that you may be more likely to get cancer in the future. You should speak to your doctor about whether any more treatment is needed.
- Atypical ductal hyperplasia can be thought of as one-step before the earliest form of cancer. It is often removed because there is a small chance that cancer cells may be found nearby.
- Flat epithelial atypia is a growth within a milk gland. It does not usually need to be removed.
- Lobular carcinoma in situ and atypical lobular hyperplasia are grouped together and called lobular neoplasia. These findings are sometimes removed because there is a small chance that cancer cells may be found nearby.
- A papilloma is a growth within a milk duct that may cause nipple discharge. Not all papillomas need to be taken out of your breast. A papilloma may be removed if it has suspicious cells or if it is causing symptoms.
- Phylloides tumors are rare tumors that are most often benign. Because they tend to grow very fast, they are usually removed.
- A radial scar (or complex sclerosing lesion) is a collection of milk ducts trapped in an area of breast tissue. Not all radial scars need to be taken out of your breast. A radial scar may be removed if it has suspicious cells.
Malignant Breast Biopsy Results
Malignant means that some cancer cells were found in your biopsy tissue. There are several types of breast cancer. Each type of breast cancer has different treatment options. You should speak to your doctor about the next steps of your treatment.
The glands of the breast are made of lobules (where milk is made) and ducts (which carry the milk to the nipple). Non-invasive cancers have not yet broken out of the milk glands into the surrounding tissues. Invasive cancers start out growing in the breast glands but have also entered the surrounding tissues. Invasive cancers may also spread outside of the breast.
- Ductal carcinoma in situ is non-invasive cancer. The cancer cells grow and expand the milk ducts but are not in the surrounding breast tissue. It is usually not life-threatening.
- Invasive ductal carcinoma is the most common type of invasive breast cancer. About 80% are this type. The cancer starts in the cells that line a milk duct and grows into the tissues outside of the duct.
- Invasive lobular carcinoma is a less common type of invasive breast cancer. About 15% are this type. The cancer starts in the part of the gland that produces milk (lobule) and grows into the tissues outside of the lobule.
- Invasive mammary carcinoma is a less common type of invasive breast cancer that has features of both ductal and lobular cancer.
- Other less common types of breast cancer are cribriform, inflammatory, medullary, mucinous, papillary, and tubular.
Your breast biopsy results may include other details that help doctors decide on your treatment. A tumor grade, for example, shows how quickly cancer cells are likely to grow and spread. Usually, the grade is between 1 and 3, with 1 being less worrisome. Tumor markers include estrogen receptor, progesterone receptor, and Her2-neu. Knowing about these markers gives your doctor a better idea of how best to treat the cancer.
Sources: Society of Breast Imaging — Sally Goudreau, Vidhi Kacharia, Vandana Dialani, Hannah Milch, Caroline Daly, and Lars Grimm for the SBI Patient Care & Delivery Committee