BI-RADS 3 on a Mammogram: What Does 'Probably Benign' Mean?

BI-RADS 3 means 'probably benign': the radiologist saw something that is very likely not cancer but wants to check it again to be safe. The American Cancer Society says a finding in this category has a very low chance of being cancer, no more than 2%. The usual next step is a repeat imaging test after a short interval, rather than a biopsy.

BI-RADS stands for Breast Imaging Reporting and Data System. It is a shared scale radiologists use so that mammogram reports are worded consistently. This guide explains the category in general terms. It cannot tell you what your own finding is or what your own risk is; that comes from the radiologist and your care team.

A BI-RADS 3 result is not a reason to ignore new symptoms while you wait for the follow-up scan. The NHS advises seeing a GP or other clinician if you notice any of the changes below, or any change in your breasts or nipples that is not normal for you. Contact the team that manages your follow-up and say that you already have a BI-RADS 3 finding.

• A new lump or swelling in the breast, chest or armpit.
• Dimpling of the skin, or skin that looks like orange peel.
• A change in skin colour, such as redness or darker skin than usual.
• A change in the size or shape of one or both breasts.
• Nipple discharge when not pregnant or breastfeeding, especially if it contains blood.
• A nipple that turns inwards, changes shape or develops a rash.

Authoritative sources put the chance as low. The American Cancer Society describes it as no more than 2%. Cleveland Clinic phrases the same idea the other way round: a greater than 98% chance that the finding is benign.

A large study reported by the Radiological Society of North America (RSNA) followed more than 43,000 women given a BI-RADS 3 assessment on mammography. About 1.9% were later diagnosed with cancer, and most of those cancers were found at or soon after the 6-month follow-up. The study authors used this to support follow-up imaging at around six months.

These figures describe large groups of people, not one person. Your care team may consider other details, such as your history and earlier imaging, when explaining what the result means for you.

Short-interval follow-up means having another imaging test sooner than your normal screening schedule. The National Cancer Institute lists a 6-month follow-up mammogram for category 3. The American Cancer Society says follow-up is usually repeat imaging in 6 to 12 months, and then regularly until the area has not changed for a while, usually at least 2 years.

Cleveland Clinic notes that the follow-up test might be a mammogram, ultrasound or MRI, depending on how the finding was first seen. Your report or letter should say which test is needed and when. If it does not, ask the imaging service or the clinician who requested the mammogram.

A biopsy is recommended for findings that look suspicious, which BI-RADS places in categories 4 and 5. A category 3 finding is different. The American Cancer Society says it is not expected to change over time but should be checked to be safe. Cleveland Clinic explains that because it is not proven benign, the radiologist wants to watch it to be sure it does not change.

So the usual plan is to monitor the area with imaging rather than sample it straight away. If you feel uneasy about waiting, that is a reasonable thing to raise. Ask your clinician why monitoring was chosen in your case, what a change on the next scan would lead to, and whether any other option fits your situation.

The radiologist compares the new images with the earlier ones. The American Cancer Society notes that findings which have not changed compared with older mammograms are not likely to be cancer. If the area is stable, the follow-up schedule usually continues until it has stayed the same for a while, and then routine screening may resume.

If the area looks different, the radiologist may give it a new category and recommend another test. Ask how and when you will receive the result, and who to contact if you have not heard back.

Practical steps can help. Book the follow-up as soon as you are told when it is due, and tell the service where your earlier images were taken so they can be compared. If you move or change provider, ask for your images and reports to be transferred.

Take the full written report with you, not only the category number. These questions can help you understand the plan.

• What exactly was seen, and where in the breast is it?
• Was this category given after a screening mammogram, or after extra views or ultrasound?
• Which test do I need next, and on what date?
• How long will follow-up continue if the area does not change?
• What would make you recommend a biopsy instead of more monitoring?
• Does my breast density or family history change the plan?
• Who should I contact if I notice a new breast change before the next scan?

On SameCase, patients and verified doctors share de-identified cases. Reading how other people with a BI-RADS 3 finding moved through follow-up imaging can help you think of questions to bring to your own appointment, such as how long monitoring lasted or what was compared.

Other people's cases cannot tell you what your finding is or what will happen next. Use them only to prepare questions, and rely on your radiologist and care team for decisions about your follow-up.

A BI-RADS 3 result is common and, in most cases, the finding turns out to be benign. The step that matters most is completing the follow-up imaging on time. Keep a copy of every report, note the next due date, and contact your clinician sooner if anything in your breasts changes.