A Screening Mammogram is a routine breast X-ray for women who do not currently have any breast symptoms. Its job is to find changes in the breast — sometimes years before a lump can be felt — when treatment is simpler and outcomes are best.
If your doctor has asked for a screening mammogram, it is a precaution, not a sign that something is wrong. Most screening mammograms come back normal.
Common Indications for a Screening Mammogram
Nigeria's 2024 national guideline recommends clinical breast examination every three years at ages 25–34, clinical examination plus ultrasound every two years at ages 35–39, annual clinical examination plus mammography at ages 40–55, and both every two years at ages 56–74. From age 75, screening is individualised according to health and preference.
These are population recommendations, not a substitute for individual advice. People at high risk—for example because of a harmful BRCA variant, a strong family history, previous high-risk breast lesion, or radiotherapy to the chest at a young age—need a specialist plan that may start earlier and include MRI. A new breast symptom needs diagnostic assessment at any age; do not wait for the next screening date.
What exactly does a Screening Mammogram show?
It shows the internal structure of both breasts — fatty tissue, glandular tissue, calcifications, and any masses. The radiologist looks for early signs of breast cancer such as tiny clusters of calcium specks, distortion of the normal tissue pattern, or new lumps.
What happens during the procedure?
- You will undress from the waist up and put on a hospital gown.
- The mammographer will position one breast at a time on a flat plate of the machine.
- A second plate will gently press down to flatten the breast for a few seconds. This compression is what produces clear images.
- Two standard views are taken of each breast — one from the top, one from the side. So four images in total.
- The whole process usually takes about 15 to 20 minutes.
Do I need to prepare for a Screening Mammogram?
A little preparation makes the test smoother:
- No fasting is required. You can eat and drink normally.
- Wear a two-piece outfit (top and trousers or a skirt). You only undress from the waist up.
- Avoid deodorant, perfume, body spray, lotions, or powder on your breasts and underarms on the day of the test. These can show up as specks on the image and confuse the radiologist.
- If you are still menstruating, try to schedule the test for the week after your period ends, when breasts are usually less tender.
How long do the results take?
A screening mammogram is usually read after you leave the centre. Turnaround and callback systems vary, so ask when the signed report will be ready, how you will receive it, and who to contact if nothing arrives. Do not assume “no call” means a normal result.
Will the test be painful?
Most women describe it as uncomfortable rather than painful, because of the compression. The discomfort lasts only a few seconds per image. If you are in real pain, tell the mammographer — they can reposition you and reduce the pressure slightly.
How often do I need a screening mammogram?
For people at average risk in Nigeria, the 2024 national guideline recommends annual mammography at ages 40–55 and every two years at ages 56–74, alongside clinical breast examination. From age 75, the decision is individual. High-risk surveillance and short-interval follow-up after an abnormal result are different from routine screening and should follow the written recommendation from your breast team.
What if my screening mammogram is not normal?
Most callbacks are not cancer
Being asked to return for more images after a screening mammogram is common and usually not because cancer was found. Most callbacks turn out to be normal tissue, cysts, or benign changes. The follow-up is called a diagnostic mammogram and may include extra views or an ultrasound.
Can I have a screening mammogram if I am breastfeeding?
Yes, when it is due or clinically indicated. Mammography does not make breast milk radioactive, and breastfeeding can continue after the test. Lactation makes breast tissue denser, so feeding or expressing milk shortly before imaging may improve comfort and image quality. Never postpone assessment of a new lump or other concerning symptom simply because you are breastfeeding.
Is a screening mammogram safe?
Mammography uses a low dose of ionising radiation. Dose varies with breast thickness, equipment, number of views, and technique, so simple background-radiation comparisons can mislead. For people in recommended age and risk groups, the expected screening benefit generally outweighs the small radiation risk.
Sources and further reading
- Nigeria Federal Ministry of Health: National Multi-Sectoral Action Plan for Non-Communicable Diseases, 2019–2025
- WHO: Breast cancer
Conclusion
A screening mammogram is a low-dose test that can find breast cancer before symptoms appear, but it is not perfect. Follow the Nigerian age- and risk-based schedule agreed with your clinician, keep previous images for comparison, and arrange diagnostic assessment promptly for any new breast change rather than waiting for screening.