If your mammogram shows something unusual, you’ll be called back for additional imaging. This happens to about 10% of women after a screening mammogram, and the vast majority of those callbacks turn out to be nothing serious. Of the women called back, only about 7% end up with a cancer diagnosis. That means roughly 93 out of 100 women who get that nerve-wracking phone call will learn the finding is benign.
Still, the waiting and not knowing can be one of the hardest parts. Here’s what actually happens at each step so you know what to expect.
What “Something” on a Mammogram Means
Mammogram results are scored on a scale from 0 to 6. A score of 0 means the images were incomplete or unclear, and the radiologist needs more information before making a call. This is the most common reason for a callback and doesn’t mean anything suspicious was found. The radiologist may simply need a better angle, want to zoom in on a particular area, or compare your new images with older ones to check for changes.
A score of 1 or 2 means no concerns. A score of 3 means something was found that has a greater than 98% chance of being noncancerous, but the radiologist wants to monitor it over time. Scores of 4 and 5 are where things get more serious. A 4 means a suspicious area that could range anywhere from a 2% to 95% chance of being cancer, depending on what it looks like. A 5 means the finding looks very likely to be cancer, with at least a 95% probability. Both of these scores lead to a biopsy recommendation.
Common Findings That Trigger a Callback
Several types of breast changes can show up on a mammogram. Calcifications are among the most common. These are tiny deposits of calcium in breast tissue, and they come in two general types. Larger, coarser calcifications with smooth, round edges are almost always benign. Smaller, irregular ones, called microcalcifications, need closer attention because their shape and pattern can sometimes signal early cancer. Fine branching microcalcifications carry the highest risk (around 78%), while amorphous or rounded, grouped calcifications are much less concerning and may just need a repeat image in six months.
Other findings include masses (which could be solid or fluid-filled), areas of density that look different from surrounding tissue, or structural changes in the breast. Many of these turn out to be cysts, fibroadenomas, or normal lymph nodes.
The Diagnostic Mammogram
Your first follow-up step is usually a diagnostic mammogram. This uses the same machine as your screening mammogram, with the same breast compression and the same prep (no deodorant or lotion). The difference is that the radiologist tailors the exam to the specific area of concern, taking additional views or magnified images of that spot. A radiologist typically reviews the images while you’re still there, so you may get preliminary information the same day.
Most abnormal screening mammograms in the U.S. are fully evaluated within three weeks, though this varies by facility. The American College of Radiology recommends that imaging centers contact women about abnormal results within five days.
When Ultrasound Is the Next Step
If the diagnostic mammogram still shows something that needs clarification, an ultrasound is often ordered next. Ultrasound is especially useful because it can distinguish between a fluid-filled cyst and a solid mass. A fluid-filled area almost always turns out to be a simple breast cyst, which is noncancerous and typically requires no treatment at all. If the area appears solid, it’s more likely a fibroadenoma (a common benign lump), though solid masses can occasionally be cancer, which is why further evaluation may follow.
In some cases, the radiologist can aspirate (drain) a cyst during the ultrasound. If fluid comes out and the lump disappears, the diagnosis is confirmed right there, and no further testing is needed.
What a Breast Biopsy Involves
If imaging can’t confirm that a finding is benign, the next step is a biopsy, where a small sample of tissue is removed and examined under a microscope. There are two main types used for breast findings.
A fine needle aspiration uses a very thin needle to withdraw cells or fluid. Recovery is quick: you can remove the bandage, shower, and return to normal activity the same night. This approach works well for evaluating cysts or checking lymph nodes, but it has limitations. Its accuracy varies widely, and inconclusive results sometimes mean additional testing is needed anyway.
A core needle biopsy uses a slightly larger needle to remove small cylinders of tissue, which gives the pathologist much more to work with. It produces a definitive diagnosis more often than fine needle aspiration and provides important details about a tumor’s characteristics that guide treatment decisions. At least three tissue samples are typically collected, and for areas with calcifications, at least five. Accuracy improves with each additional sample: one sample yields a clear result about 74% of the time, while four samples reach about 98%.
What to Expect During and After a Biopsy
You’ll need to stop taking blood-thinning medications and supplements like aspirin, ibuprofen, fish oil, and vitamin E five days before a core needle biopsy. You can eat a light meal beforehand, and you should wear a supportive sports bra and a comfortable two-piece outfit. The procedure itself is done with local numbing, so you’ll be awake the whole time. Most people can drive themselves home afterward.
After a core needle biopsy, a waterproof dressing stays on for seven days. You’ll ice the area for about an hour, then 10 minutes every hour until bedtime. Plan to rest at home for the remainder of that day. Avoid strenuous activity, including housework, yard work, and exercise, for three days. For pain, stick to acetaminophen (Tylenol) only, since anti-inflammatory painkillers can increase bleeding. After three days, you can resume your regular medications and normal routine.
Waiting for Biopsy Results
Biopsy results typically come back within a few days to a week, though some facilities take longer. The pathologist examines the tissue to determine whether cells are normal, benign, atypical, or cancerous. If cancer is found, the tissue sample also provides details about the type and behavior of the cancer that help shape a treatment plan.
It’s worth knowing that even among women who undergo biopsy, a significant number receive benign results. The abnormal finding on your mammogram has already been filtered through multiple layers of imaging by this point, and each step narrows the pool of women who actually have cancer.
If Additional Imaging Is Needed
In certain situations, your doctor may recommend breast MRI or contrast-enhanced mammography instead of, or in addition to, standard imaging. MRI is particularly useful for women with dense breast tissue or those at high risk for breast cancer. However, MRI tends to produce more false positives, meaning it flags areas that turn out to be nothing. Contrast-enhanced mammography performs better for evaluating suspicious calcifications and is faster, more accessible, and an option for women who can’t undergo MRI due to claustrophobia or implanted medical devices.
The Monitoring Path for Low-Risk Findings
Not every abnormal mammogram leads to a biopsy. Findings scored as “probably benign” (category 3) are monitored with repeat imaging, usually starting six months after the initial mammogram. If the area stays the same over time, it’s reclassified as benign and returns to routine screening. If it changes, a biopsy may then be recommended. This watch-and-wait approach works because these findings have a less than 2% chance of being cancer, and monitoring catches the rare cases that do progress while sparing the vast majority of women from an unnecessary procedure.