A BI-RADS 0 result means the radiologist who read your mammogram could not reach a final conclusion from the screening images alone and needs more information before giving you a definitive assessment. It is not a diagnosis of cancer, and it is not an all-clear. The “0” in the BI-RADS system stands for “incomplete,” and the practical translation is straightforward: you will be called back for additional imaging, sometimes within days, sometimes within a few weeks. Roughly one in ten screening mammograms receives this designation, and the vast majority of women who get one turn out to have nothing wrong.
Why a Mammogram Comes Back Incomplete
Screening mammograms are designed to be fast and standardized. Two views of each breast are taken, and a radiologist reviews the images looking for anything that stands out. But breast tissue is complicated. It overlaps in ways that can mimic suspicious findings, and sometimes a real abnormality hides behind dense tissue or lands at the edge of the image where positioning wasn’t ideal. When a radiologist spots something that could be a problem but could just as easily be a quirk of how the tissue compressed or overlapped, the responsible move is to assign BI-RADS 0 rather than guessing.
Several specific situations trigger a callback. The most common is an asymmetry, where one area of one breast looks different from the corresponding spot on the other side. This can be caused by normal anatomical variation, but it can also signal a developing mass. Other triggers include a vague density that could be overlapping tissue, a cluster of tiny calcifications that needs magnification to evaluate, or a portion of the breast that wasn’t fully captured in the standard views. Positioning errors, while not frequent, do happen and can obscure parts of the breast that need to be seen.
Having prior mammograms available for comparison reduces the chances of getting a BI-RADS 0. If the radiologist can pull up your earlier images and see that the same finding has been sitting there unchanged for years, they can often call it benign without recalling you. Research has shown that comparing against multiple prior exams is especially helpful because breast tissue positioning varies from year to year; the more prior images available, the better the odds of finding one where the tissue lined up similarly to the current exam, making stability easier to confirm.1PubMed Central. Improving Screening Mammography Outcomes through Comparison with Multiple Prior Mammograms This is one reason first-time mammograms are more likely to result in a callback than subsequent ones.
How Common BI-RADS 0 Is
National benchmarking data from the Breast Cancer Surveillance Consortium put the average abnormal interpretation rate for screening mammography at about 12%, meaning roughly one in eight or nine women screened gets flagged for something. Not all of those are BI-RADS 0 specifically, since some are assigned higher suspicion categories right away, but BI-RADS 0 makes up a large share of recalls. In double-reading programs where two radiologists independently review each mammogram, about a third of all recalls were assigned BI-RADS 0.2PubMed. Arbitration of discrepant BI-RADS 0 recalls by a third reader at screening mammography lowers recall rate but not the cancer detection rate and sensitivity at blinded and non-blinded double reading
These numbers also reveal that many radiologists recall more women than guidelines recommend. Only about 59% of radiologists in community practice met the recommended benchmarks for abnormal interpretation rates, and just 63% achieved the recommended specificity levels.3PubMed Central. National Performance Benchmarks for Modern Screening Digital Mammography: Update from the Breast Cancer Surveillance Consortium That doesn’t mean those radiologists are doing something wrong per se. There’s a well-known tension in mammography between catching every cancer (sensitivity) and avoiding unnecessary callbacks (specificity), and most radiologists err on the side of caution. But it does mean that the recall rate you personally experience may vary depending on where you’re screened.
What Happens After You Get Called Back
The additional imaging that follows a BI-RADS 0 result usually starts with a diagnostic mammogram. Unlike the screening exam’s two standard views, the diagnostic session is tailored to whatever caught the radiologist’s eye. That might mean spot compression views, where a smaller paddle presses on just the area in question to spread the tissue apart and get a clearer look. It might mean magnification views for tiny calcifications, or rolled views where the breast is shifted to separate overlapping structures. The radiologist is essentially trying to answer one question: does this finding persist when we look at it from different angles, or does it disappear?4PubMed. Asymmetric mammographic findings based on the fourth edition of BI-RADS: types, evaluation, and management
In many cases, a targeted ultrasound is performed the same day as the diagnostic mammogram. Ultrasound is particularly useful when the mammogram shows a density or asymmetry, because it can quickly determine whether the area in question is a solid mass, a fluid-filled cyst, or just normal tissue that happened to look unusual on the X-ray image. One study tracking women whose screening mammograms received BI-RADS 0 found that ultrasound resolved the question in about 61% of cases, with the majority of those women reclassified as BI-RADS 2, meaning benign. Among the remaining cases where ultrasound showed something suspicious enough to warrant a biopsy, about 10 out of 35 turned out to be cancer.5PubMed Central. Breast ultrasound diagnostic performance and outcomes for mass lesions using Breast Imaging Reporting and Data System category 0 mammogram
What matters most to understand here is that BI-RADS 0 is a temporary holding category. After the diagnostic workup, you will be reclassified into one of the definitive BI-RADS categories: 1 (negative), 2 (benign), 3 (probably benign, short-interval follow-up recommended), 4 (suspicious), or 5 (highly suggestive of cancer). The majority land in categories 1 or 2 and resume routine annual screening.
What Are the Actual Odds of Cancer?
This is the question most women really want answered, and the honest answer is that the odds are low but not zero. Among BI-RADS 0 recalls specifically, the positive predictive value, meaning the fraction of callbacks that actually turn out to be cancer, sits in the range of about 7%.2PubMed. Arbitration of discrepant BI-RADS 0 recalls by a third reader at screening mammography lowers recall rate but not the cancer detection rate and sensitivity at blinded and non-blinded double reading That means roughly 93 out of 100 women called back for a BI-RADS 0 finding will not have cancer. The overall positive predictive value for all mammographic recalls (including those assigned higher suspicion categories at screening) runs around 4–5%.3PubMed Central. National Performance Benchmarks for Modern Screening Digital Mammography: Update from the Breast Cancer Surveillance Consortium
Certain features on the mammogram do raise the probability that a recalled finding will turn out to be malignant. If the asymmetry the radiologist spotted is accompanied by architectural distortion or associated calcifications, the odds of cancer climb sharply. A study of mammographic asymmetries that went to biopsy found that distortion alongside the asymmetry was associated with about 15 times the odds of malignancy, and the presence of calcifications about 10 times the odds.6Oxford Academic (Journal of Breast Imaging). Imaging, Patient, and Diagnostic Radiologist Factors Associated With Malignancy for Mammographic Asymmetries Undergoing Biopsy Older age and a personal history of breast cancer also increased the likelihood. But these are factors the radiologist evaluates during the diagnostic workup; they’re not things you can determine from a screening BI-RADS 0 result letter alone.
The Emotional Side of a Callback
Getting a letter or phone call telling you your mammogram was “incomplete” and you need to come back is anxiety-inducing for most women, even when the language is carefully chosen. Research on the psychological effects of mammogram recalls shows that women who receive a false-positive result (meaning they were called back but ultimately found to have nothing wrong) experience a temporary spike in anxiety. One large study of Norwegian women found the anxiety was real but transient, and depression levels in recalled women were actually lower than the general population average.7PubMed. Recall mammography and psychological distress
How a woman responds to a BI-RADS 0 result depends heavily on her baseline relationship with healthcare. A qualitative study of patient experiences with BI-RADS 0 results found that women who had existing trust in the healthcare system were more likely to search for information online and feel reassured by what they found, while women with pre-existing mistrust often found that searching for information made their anxiety worse.8Patient Experience Journal. Navigating Uncertainty: Patient Experiences of BIRADS 0 Mammogram Results The takeaway is that a BI-RADS 0 result hits people differently, and it’s worth being deliberate about where you look for information while you wait.
Getting to the Follow-Up Appointment
A BI-RADS 0 result is only useful if it actually leads to a diagnostic workup. This is where the system sometimes breaks down. A systematic review of follow-up after abnormal screening mammograms found that failure to complete the recommended follow-up within three months ranged from 7% to 33%, and by six months, between 27% and 72% of women still hadn’t completed it.9PubMed Central. Delayed or failure to follow-up abnormal breast cancer screening mammograms in primary care: a systematic review The reasons are a tangle of systemic and personal factors: miscommunication between the imaging center and the primary care provider, inconvenient clinic hours, lack of consistent providers who track results, and sometimes the woman herself not fully understanding what the result means or what she needs to do next.
Direct outreach from imaging centers can make a dramatic difference. One study tracked the effect of adding telephone communication to the standard notification letter and found that the share of women completing their diagnostic follow-up within 60 days rose from about 73% to 90% over several years of implementing the program. The median time to follow-up also dropped from 28 days to just 9 days.10PubMed. Impact of Telephone Communication on Patient Adherence With Follow-Up Recommendations After an Abnormal Screening Mammogram If your imaging center contacts you directly to schedule the diagnostic appointment rather than leaving it to you to arrange, that’s a good sign that the facility takes follow-up seriously.
Where you were screened also matters. Women who had their initial mammogram at a mobile screening unit were about twice as likely to experience delays in follow-up compared to those screened at a fixed clinic.11PubMed Central. Delays in Follow-up Care for Abnormal Mammograms in Mobile Mammography Versus Fixed-Clinic Patients Mobile mammography programs serve an important role in reaching underserved communities, but the handoff from screening to diagnosis can be harder when the screening location isn’t a permanent facility with scheduling infrastructure.
Racial Disparities in Follow-Up
The delays described above don’t fall evenly across the population. African American and Hispanic women waited significantly longer for diagnostic follow-up after an abnormal mammogram compared to non-Hispanic white women, with median times of 20 and 21 days versus 14 days. Those disparities persisted even after accounting for age, insurance status, and income.12PubMed Central. Racial/Ethnic Disparities in Time to Follow-Up after an Abnormal Mammogram
For BI-RADS 0 results specifically, the gaps are starker. Black women were about 29% less likely than white women to receive a diagnostic mammogram following a BI-RADS 0 screening result, and about 26% less likely to proceed to biopsy when one was indicated. Nearly a quarter of BI-RADS 0 mammograms among Black women were not followed by diagnostic imaging within 30 days, compared to about 15% among white women.13Journal of Clinical Oncology. Racial disparities in diagnostic follow-up following BIRADS 0 mammogram These aren’t just statistical abstractions. Each step of delay compounds the disadvantage, potentially allowing any cancer that does exist to advance before treatment begins.
How 3D Mammography Reduces Unnecessary Callbacks
One of the most effective advances in reducing BI-RADS 0 results has been digital breast tomosynthesis, commonly called 3D mammography. Instead of taking a single flat X-ray image of each view, tomosynthesis sweeps the X-ray tube in an arc and reconstructs thin slices through the breast. This makes it much easier to tell whether a suspicious-looking density is real or just overlapping normal tissue.
Multiple studies have shown substantial reductions in callback rates when tomosynthesis is added to standard mammography. One prospective trial found a 33% reduction in recalls among women without breast cancer when tomosynthesis was used alongside standard digital mammography.14PubMed Central. Recall rate reduction with tomosynthesis during baseline screening examinations – an assessment from a prospective trial A reader study testing one-view and two-view tomosynthesis found that the noncancer recall rate dropped from about 44% with digital mammography alone to 24% with two-view tomosynthesis added.15PubMed. Diagnostic accuracy and recall rates for digital mammography and digital mammography combined with one-view and two-view tomosynthesis: results of an enriched reader study Community practice data confirmed the pattern, showing about a 16% relative reduction in recall rates with 3D mammography.16PubMed. Clinical performance metrics of 3D digital breast tomosynthesis compared with 2D digital mammography for breast cancer screening in community practice
If you’ve been getting callbacks on standard mammograms because of dense or overlapping tissue, asking whether your facility offers tomosynthesis is a reasonable conversation to have. Most major imaging centers now offer it, and many insurance plans cover it the same as standard screening. It won’t eliminate all callbacks, but it meaningfully reduces the ones caused by overlapping tissue mimicking a problem that isn’t there.
What a BI-RADS 0 Callback Can Cost You
Federal law requires insurers to cover screening mammograms without cost-sharing, but the diagnostic imaging that follows a BI-RADS 0 result is classified differently. Once you cross from “screening” to “diagnostic,” you may be subject to copays, coinsurance, or deductible charges depending on your plan. A large analysis of insurance claims found that women who underwent additional breast imaging after a screening mammogram paid an average of about $75 in out-of-pocket costs for those imaging services alone, compared to roughly $1 for women who only had the screening exam.17JAMA Network Open. Patient Cost-Sharing and Utilization of Breast Cancer Diagnostic Imaging by Patients Undergoing Subsequent Testing After a Screening Mammogram
Those costs are not trivial for everyone, and the same study found that cost-sharing structures influenced behavior. Women in plans with higher coinsurance or deductible requirements underwent slightly fewer follow-up imaging procedures per thousand patients than women in copay-dominant plans. In other words, the financial design of the insurance plan appeared to discourage some women from completing recommended diagnostic workups. Some states have passed or are considering legislation to eliminate cost-sharing for diagnostic breast imaging after an abnormal screening result, but coverage varies by state and plan type.
The Role of AI in Mammography Reading
Artificial intelligence tools are increasingly being tested and deployed alongside radiologists reading screening mammograms, and one of their potential benefits is reducing the volume of BI-RADS 0 results without missing cancers. A prospective multicenter study found that radiologists using AI-assisted detection caught about 14% more cancers per thousand screens compared to radiologists reading without AI, and they did so without any significant increase in the recall rate.18Nature Communications. Artificial intelligence for breast cancer screening in mammography (AI-STREAM): preliminary analysis of a prospective multicenter cohort study
Simulation studies exploring how AI might be integrated into screening programs have shown that some strategies could cut the radiologist workload nearly in half while maintaining or improving cancer detection. In one retrospective analysis, an AI system used to triage mammograms routed about 98% of exams directly to a “negative” pathway (no further action needed) and flagged only about 2% as suspicious for human review, still achieving a higher cancer detection rate than the standard two-radiologist reading model and a lower recall rate.19The Lancet Digital Health. Comparative evaluation of strategies for integrating artificial intelligence into breast cancer screening programmes: a retrospective simulation study These tools are not yet standard in most imaging centers, but widespread adoption in the coming years could meaningfully reduce the number of women who get a BI-RADS 0 letter and the anxiety that comes with it.
Understanding the Letter You Receive
The notification letter you get after a BI-RADS 0 result matters more than it might seem. Research into the readability of these letters has found that standard recall letters are often written at a reading level well above what most patients can comfortably understand. One quality-improvement project found that typical BI-RADS 0 recall letters scored at roughly a 12th-grade reading level, and only about 41% of patients rated them as understandable. After the letters were rewritten in plainer language, the reading level dropped to about a 7th-grade level and understandability ratings jumped to 90%.20PubMed Central. Quality improvement project: Patient-centered breast imaging letters Actionability, meaning how clearly the letter told the patient what to do next, also improved dramatically.
If the letter you receive is confusing, vague, or doesn’t clearly tell you whether you need to do something and by when, that’s a failure of the communication rather than a reason to ignore it. Call the imaging center directly and ask three questions: what did the radiologist see, what imaging do I need next, and how soon should it happen? Most diagnostic workups after a BI-RADS 0 are scheduled within a few weeks of the screening result, and there is no medical reason for significant delay.