A breast biopsy is a procedure to remove a small sample of breast tissue for examination under a microscope. It is the most reliable method to determine if a suspicious breast lesion is cancerous. The accuracy of a breast biopsy depends on several factors, including the type of biopsy performed, the expertise of the medical team, and the characteristics of the abnormality.
What is a breast biopsy?
A breast biopsy involves removing some cells or tissue from a suspicious area in the breast so they can be examined under a microscope. There are several types of breast biopsies:
- Fine needle aspiration (FNA) biopsy: A thin needle is used to withdraw fluid and cells from a breast lump.
- Core needle biopsy: A larger needle is used to remove a small cylinder of tissue from the suspicious area.
- Vacuum-assisted biopsy: Uses vacuum pressure to collect multiple tissue samples through a needle.
- Surgical biopsy: Involves either a lumpectomy (removing the lump and some surrounding tissue) or incisional biopsy (removing part of the abnormal area) to obtain a tissue sample.
The type of biopsy performed depends on factors such as the size and location of the abnormal area.
How accurate is a breast biopsy for diagnosing breast cancer?
Breast biopsies are very accurate for diagnosing breast cancer. However, no test is 100% accurate. According to studies, the accuracy ranges from:
- Fine needle aspiration biopsy: 60-98% accurate
- Core needle biopsy: 70-100% accurate
- Surgical biopsy: Close to 100% accurate
So a surgical biopsy, which removes the most tissue, is the most accurate. But less invasive options like a core needle biopsy also have a high degree of accuracy.
What affects the accuracy of a breast biopsy?
Some key factors that influence the accuracy of a breast biopsy include:
Type of biopsy
As mentioned above, surgical biopsies that remove more tissue tend to be more accurate than less invasive needle biopsies.
Expertise of healthcare team
An experienced radiologist and pathologist are essential for obtaining and analyzing an accurate sample. Their skill and expertise strongly impact the reliability of the results.
Number of core samples obtained
For core needle biopsies, taking more samples (at least 5-6) improves accuracy vs only taking 1-2 samples. The more samples, the less likely cancer will be missed.
Breast density
Dense breast tissue can sometimes obscure abnormalities on imaging tests like mammograms. This makes obtaining a sufficient biopsy sample from the right location more challenging.
Size of lesion
Larger lesions are easier to biopsy and assess compared to very small lesions detected only on imaging.
Characteristics of abnormality
Certain breast abnormalities like calcifications, architectural distortions or complex sclerosing lesions are more difficult to diagnose from biopsy samples.
Does a benign breast biopsy result completely rule out cancer?
In most cases, a benign (non-cancerous) breast biopsy finding means there is no breast cancer present. However, in rare instances, a biopsy may miss some cancer cells, leading to a false negative result.
According to studies, the false negative rate for breast biopsies is estimated to be:
- Fine needle aspiration biopsy: up to 10%
- Core needle biopsy: 1-7%
- Surgical biopsy: less than 1%
So even with an initially benign result, it’s important to follow up on suspicious breast abnormalities that persist despite a negative biopsy. Repeat imaging and testing may be warranted.
Should you get a second opinion on a breast biopsy result?
Most of the time, a breast biopsy result is definitive so a second opinion is not required. However, in certain situations, it may be advisable:
- If there is uncertainty about the diagnosis
- If you have a strong family history of breast cancer
- If you question the initial biopsy procedure or handling of tissue sample
- If you do not fully understand the biopsy results
- If the initial biopsy was not done by a breast specialist
Discussing the pros and cons of a second opinion with your doctor can help determine if it would be beneficial in your individual situation.
What are some limitations of breast biopsies?
While very accurate, breast biopsies do have some limitations including:
- Discomfort and anxiety for the patient
- Risk of bleeding and infection
- Scarring at the biopsy site
- Only samples a small portion of the total abnormal area
- Potential for sampling errors and false negative results
- Invasive procedures that may require needles or surgery
Careful attention is required during the procedure and analysis of tissue to maximize accuracy and minimize false results.
What happens after a breast biopsy?
The steps after a breast biopsy include:
- The tissue sample is sent to a pathology lab for analysis.
- It takes about 1-2 weeks to get the test results.
- A follow-up appointment is scheduled with your doctor to discuss the results.
- If cancer is diagnosed, additional tests are done to determine treatment options.
- Benign results may require continued monitoring with regular mammograms.
Let your doctor know if you experience any concerning symptoms like bleeding, swelling, pus, or redness at the biopsy site.
Can you develop breast cancer after a benign breast biopsy?
Yes, it is still possible to develop breast cancer after a benign biopsy result. Here’s some key info:
- Risk is not significantly increased in the breast that had the benign biopsy.
- Risk of developing cancer in the opposite breast is unchanged.
- In rare cases, biopsy may miss a cancerous lesion that progresses over time.
- Benign lesions like atypical ductal hyperplasia may slightly increase long-term cancer risk.
- Follow-up screening is important even after benign biopsy results.
According to studies, the likelihood of developing breast cancer within 15 years after a benign biopsy result is an average of 10-17%.
Should you have regular screening after a benign breast biopsy?
Yes, it is important to continue with regular mammograms and clinical breast exams even after a benign breast biopsy. This allows early detection of any new abnormalities that may develop over time.
Here are some general screening recommendations:
- Women with average risk: Annual mammogram starting at age 40.
- Women with higher risk: Begin screening earlier, get MRI in addition to mammograms.
- Clinical breast exams every 1-3 years starting in 20s.
- Report any new breast changes to your doctor promptly.
Discuss an appropriate screening schedule with your doctor based on your individual risk factors.
Key takeaways on breast biopsy accuracy
- Breast biopsies are very accurate for diagnosing breast cancer, with surgical biopsy close to 100% accurate.
- Fine needle and core needle biopsies have a small false negative rate of 1-10%.
- Benign biopsy results still warrant continued screening due to cancer risk.
- An experienced medical team and proper tissue sampling are key to maximize accuracy.
- Discuss any concerns or need for second opinion with your doctor.
While not perfect, biopsies are an important diagnostic tool to evaluate suspicious breast lesions. Understanding their capabilities and limitations allows appropriate use and follow up.